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Tamilnadu State Board New Syllabus Samacheer Kalvi 11th Physics Guide Pdf Chapter 1 Nature of Physical World and Measurement Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 11th Physics Solutions Chapter 1 Nature of Physical World and Measurement

11th Physics Guide Nature of Physical World and Measurement Book Back Questions and Answers

Part – I:
I. Multiple choice questions:

Question 1.
One of the combinations from the fundamental physical constants is \(\frac { hG }{ G }\), The unit of this expression is.
(a) Kg²
(b) m³
(c) S^-1
(d) m
Answer:
(a) Kg²

Question 2.
If the error in the measurement of radius is 2%, then the error in the determination of volume of the sphere will be:
(a) 8%
(b) 2%
(c) 4%
(d) 6%
Answer:
(d) 6%

Question 3.
If the length and time period of an oscillating pendulum have errors of 1% and 3% respectively then the error in measurement of acceleration due to gravity is: [Related to AMPMT 2008]
(a) 4%
(b) 5%
(c) 6%
(d) 7%
Answer:
(d) 7%

Question 4.
The length of a body is measured as 3.15m, if the accuracy is 0.01m, then the percentage error in the measurement is:
(a) 351%
(b) 1%
(c) 0.28%
(d) 0.035%
Answer:
(c) 0.28%

Question 5.
Which of the following has the highest number of significant figure?
(a) 0.007 m²
(b) 2.64 x 1024 Kg
(c) 0.0006032 m²
(d) 6.3200 J
Answer:
(d) 6.3200 J

Question 6.
If π = 3.14, then the value of π² is:
(a) 9.8596
(b) 9.860
(c) 9.86
(d) 9.9
Answer:
(c) 9.86

Question 7.
Which of the following pairs of physical quantities have same dimension?
(a) force and power
(b) torque and energy
(c) torque and power
(d) force and torque
Answer:
(b) torque and energy

Question 8.
The dimensional formula of planck’s constant h is _____________. [AMU, Main, JEE, NEET]
(a) [ML² T^-1]
(b) [ML²T^-3]
(c) [MLT^-1]
(d) [ML³T^-3]
Answer:
(a) [ML² T^-1]

Question 9.
The velocity of a particle v at an instant t is given by v = at + bt² the dimension of b is _____________
(a) [L]
(b) [LT^-1]
(c) [LT^-2]
(d) [LT^-3]
Answer:
(d) [LT^-3]

Question 10.
The dimensional formula for gravitational constant G is _____________. [Related to AIPMT 2004]
(a) [ML³T^-2]
(b) [M^-1L³T^-2]
(c) [M^-1 L^-3T^-2]
(d) [ML^-3T²]
Answer:
(b) [M^-1L³T^-2]

Question 11.
The density of a material is CGS system of units Is 4 g cm^-3. In a system of units in which unit of length is 10cm and unit of mass is 100g, then the value of density of material will be:
(a) 0.04
(b) 0.4
(c) 40
(d) 400
Answer:
(c) 40

Question 12.
If the force is proportional to square of velocity, then the dimension of proportionality constant is _____________. [JEE 2000]
(a) [ML T⁰]
(b) [ML T^-1]
(c) [ML^-2T]
(d) [ML^-1T⁰]
Answer:
(d) [ML^-1T⁰]

Question 13.
The dimension of (µ⁰ε⁰)^{\(\frac { -1 }{ 2 }\)} is _____________. [Main AIPMT 2011]
(a) length
(b) time
(c) velocity
(d) force
Answer:
(c) velocity

Question 14.
Planck’s constant (h), speed of light in vacuum (c) and Newton’s gravitational constant (G) are takers as three fundamental constants. Which of the following combinations of these has the dimension of length? [NEET 2016 (phase II)]

Answer:

Question 15.
A length-scale (l) depends on the permittivity (c) of a dielectric material Boltzmann constant (Kb), the absolute temperature (T), the number per unit volume (n) of certain charged particles, and the charge (q) carried by each of the particles. Which of the following expression for L is dimensionally correct? [JEE (advance(d) 2016 ]

Answer:

II. Short Answer Questions:

Question 1.
Briefly explain the types of physical quantities?
Answer:
Physical quantities are classified into two types. There are fundamental and derived quantities. Fundamental or base quantities are quantities which cannot be expressed in terms of any other physical quantities. These are length, mass, time, electric current, temperature, luminous intensity, and amount of substance.
Quantities that can be expressed in terms of fundamental quantities are called derived quantities. For example, area, volume, velocity, acceleration, force.

Question 2.
How will you measure the diameter of the moon using the parallax method?
Answer:
In order to determine the diameter of the moon, initially, a distance of the moon is calculated using the parallax method. Let D be the distance of the moon from the earth. Let d be the diameter of the moon. Let ∝ be the angular size of the angular diameter of the moon (ie) the angle subtended by d at the earth.

We have ∝ = d/D
d = ∝ D
The angle ∝ can be measured from the same location on the earth. When two diametrically opposite points of the moon are viewed through a telescope, the angle between the two directions gives the angular size or angular diameter. Since D is the known to size or diameter d of the moon can be determined.

Question 3.
Write the rules for determining significant figures.
Answer:
(1) All non zero digits are significant
Example: 1342 has 4 significant figures

(2) All zeros between two non-zero digits are significant
Example: 2008 has four significant figures

(3) All zeros to the right of non-zero digit but to the left of the decimal point are significant.
Example: 3070.00 has 4 significant figures.

(4) The trailing zeros are not significant, ie in the number without a decimal point. All zeros are significant if they come from the measurement.
Example: 4000 has one significant figure.

(5) If a number is less than 1, the zero (s) on the right of the decimal point but to the left of the first non-zero digit are not significant.
Example: 0.0034 has 2 significant figures.

(6) All zeros to the right of the decimal point and to the right of non zero digits are significant
Example: 40.00 has four significant figures.

(7) The number of significant figures does not depend on the system of units used.
Example: 1.53cm, 0.0150cm, 0.0000153 Km all have three significant figures.

(8) The power of 10 is irrelevant to the determination of significant figures
Example: 5.7 x 10² cm has two significant figures.

Question 4.
What are the limitations of dimensional analysis?
Answer:
(1) This method gives no information about the dimensionless constants in the formula. Like 1, 2,7i, e etc. ie they can not be determined using this analysis.

(2) This method can not decide whether the given quantity is a scalar or a vector.

(3) Using this method one cannot derive relations involving trigonometric, exponential and logarithmic functions.

(4) It cannot be applied to an equation involving more than three physical quantities.

(5) It can be used to check whether a given physical relation is dimensionally correct or not. The physical correctness can not be checked using this
For example:
s = ut + 1/3 at² is dimensionally correct were as physically not correct, as the correct equation is s = ut + 1/2at².

Question 5.
Define precision and accuracy. Explain with one example.
Answer:
The accuracy of a measurement is a measure of how close the measured value is to the true value of the quantity. The precision of measurement is the closeness of two or more measured values to each other.

The true value of a certain length is near 5.678 cm. In one experiment, using a measuring instrument of resolution 0.1 cm, the measured value is found to be 5.5 cm. In another experiment using a measuring instrument of greater resolution, say 0.01 cm, the length is found to be 5.38 cm. We find that the first measurement is more accurate as it is closer to the true value, but it has lesser precision. On the contrary, the second measurement is less accurate, but it is more precise.

III. Long Answer Questions:

Question 1.
State the principle of homogeneity and explain with an example.
Answer:
The principle of homogeneity of dimensions states that the dimensions of all the term in the physical expression should be same. This principle is used to check the correctness of the equation
For example
V² = U² + 2as
Writing dimensions on both sides
[LT^-1]² = [LT^-1]² + [LT^-1]²
[L² T²] = [L² T²] + [L²T^-2]
Here the dimensions of all the terms in the expression are same and equal to[L²T^-2]
So the equation is dimensionally correct.

Question 2.
Write short notes on the following.
(a) unit
(b) rounding off
(c) dimensionless quantity
Answer:
(a) Unit:
Unit of a physical quantity is defined as an arbitrarily chosen standard of measurement of a quantity which is accepted internationally.

The units in which the fundamental quantities are measured are called fundamental or base units and the units of measurement of all other physical quantity which can be obtained by a suitable multiplication or division of powers of fundamental units are called as derived units, example area, volume.

(b) Rounding off:
While doing calculations, the result got should not has too many figures. If no case the result have more significant figures than the figures involved in the data used for calculating. The result of calculation with numbers containing more than one uncertain digits should be rounded off.

Example :
18.35 when rounded off to 3 digits 18.4
19.45 when rounded off to 3 digits 19.4
101.55 x 10⁶ when rounded off to four digits 101.6 x 10⁶.

(c) Dimensionless quantity:
There are two types of dimensionless quantities – (i) dimensionless variable and (ii) dimensionless constant.

• Dimensionless variables – Physical quantities which have no dimensions but have variable values are called dimensionless variables.
  Examples: specific gravity, strain, refractive index, etc.
• Dimensionless constants – Quantities which have constant values and also have no dimension are called dimensionless constants.
  Example: π, e, numbers, etc.

Question 3.
What do you mean by the propagation of errors? Explain the propagation of errors in addition and multiplication.
Answer:
A number of measured quantities may be involved in the final calculation of an experiment. Different types of instruments might have been used for observation.

So the errors in the final result depends on –
(i) The error in individual measurements.
(ii) On the nature of mathematical operations.

The various possibilities of the propagation or combination of errors in different arithmetical operations are called propagation of errors.

Error in addition (or) sum of two quantities:
Let ∆A and ∆B be the absolute errors in measuring two quantities A and B respectively. Then
Measured value of A = A ± AA
Measured value of B = B ± AB
Consider sum A + B = Z
The error ∆Z in Z is given by
Z + ∆Z = (A ± ∆A) + (B ± ∆B).
= (A + B ) ± (∆A + ∆B)
Z + ∆Z = Z ± (∆A + ∆B)
∆Z = ∆A + ∆B
The maximum possible error in the sum of two quantities is equal to the sum of the absolute errors in the individual quantities.

Errors in multiplication (or) product of two quantities:
Let ∆A and ∆B be the absolute errors in the two quantities A and B respectively. Consider the product Z = AB
The error ∆Z in z given by
Z ± ∆Z = (A ± ∆A) (B ± ∆B)
= (AB) ± (A ∆ B) ± (B ∆ A) ± (∆A . ∆B)
Z ± ∆ Z = Z ± (A ∆ B) (B ∆ A) + (∆A . ∆B)
LHS by Z & RHS by AB = Z.
1± \(\frac { ∆ Z }{ Z }\) = 1 ± \(\frac { ∆ B }{ B }\) ± \(\frac { ∆ A }{ A }\) ± \(\frac { ∆A.∆B }{ AB }\)
Here \(\frac { ∆A.∆B }{ AB }\) can be neglected as \(\frac { ∆A}{ A }\) & \(\frac { ∆B }{ B }\) are small
∴ The maximum fractional error in Z is
\(\frac { ∆ Z }{ Z }\) = ±\(\frac { ∆A }{ A }\) x \(\frac { ∆B }{ B }\)
∴ The maximum fractional error in the product of two quantities is equal to the sum of fractional errors is the individual quantities.

Question 4.
Explain in detail various types of errors.
Answer:
The uncertainty in a measurement is called an error.
There are 3 types of errors namely –

1. Random error
2. Systematic error
3. Gross error.

1. Systematic errors – These are reproducible inaccuracies that are consistently in the same direction. These occur often due to problem that persists throughout the experiment. Systematic errors are further classified as

• instrumental error
• imperfection in experimental technique or procedure
• personal errors
• errors due to external causes
• least count error.

(a) Instrumental error: When an instrument is not calibrated properly at the time of manufacture instrumental errors may occur.

Example: If the measurement is made with a meter scale whose end is worn out the result obtained will have errors.

Correction – These errors can be corrected by choosing the instrument carefully.

(b) Imperfections in experimental technique or procedure: These errors arise due to limitations in the experimental arrangement.

Example: While performing experiments with a calorie meter, if there is no proper insulation, there will be radiation losses. This results in an error.

Correction – Necessary steps and corrections should be applied and followed while performing experiments.

(c) personal errors: These errors are due to individuals performing the experiments., maybe due to incorrect initial setting up of the experiment or carelessness of the individuals making the observation due to improper precautions.

(d) Errors due to external causes: The change in external conditions during experiments can cause error in measurement.

Example: Changes in temperature, humidity or pressure during measurement may affect the result of the measurement.

(e) Least count error: Least count is the smallest value that can be measured by the measuring instrument and the error due to this measurement is the least count error. The instrument’s resolution is the cause of the error. The error is half of the least value measured by the device.

Correction – Least count error can be reduced by using a high precision instrument for measurement.

(2) Random errors – Random errors may arise due to random and unpredictable variations is experimental conditions like pressure, temperature voltage supply etc., Errors may also due to persona! errors by the observer. Random errors are sometimes called “Chance errors”.

Example: While measuring the thickness of a wire using a screw gauge, different readings are taken in different trails.

Correction – By taking the arithmetic mean of all readings observed may reduce the random error and the mean value is taken as best possible true value.

(3) Gross errors – The error caused due to sheer carelessness of an observer is called gross error.
Examples: Improper setting of the instrument Making wrong observations without bothering about the sources of errors and precautions. Using wrong values in calculation Recording wrong observations

Correction – This error can be minimized only when the observer is careful and mentally alert.

Question 5.
(i) Explain the use of screw gauge and vernier calipers in measuring smaller distances:
(ii) Write a note a triangular method and radar method to measure large distances.
Answer:
Measurement of small distances by screw gauge and vernier calipers screw gauge : The screw gauge is an instrument used for measuring accurately the dimensions of objects up to a maximum of about 50 mm. The principle of the instrument is the magnification of linear motion using the circular motion of a screw. The least count of screw gauge is 0.01 mm.

Vernier calipers: A vernier caliper is a versatile instrument for measuring the dimensions of an object namely diameter of a hole or the depth of a hole. The least count of vernier caliper is a 0.01 cm.

Measurement of larger distances: For measuring larger distance such as height of a tree, distance of a moon or a planet from earth, the triangulation method, parallax method and radar method are used.

(a) Triangulation method for the height of an accessible object:

Let AB = h, be the height of a tree, to be measured. Let C be the point of observation at a distance X from B. Using a range finder placed
at C, ∠ACB = θ is measured.
∴ Considering ∆ ABC,
tan θ = \(\frac { AB }{ BC }\)
h = x tan θ
By knowing x, h can be calculated.

(b) Radar method:
RADAR is an acronym of Radio detection and ranging. A RADAR can be used to measure the distance of near planet, moon, enemy planes, moving as well as stationary targets etc. In this process, Radio signals are transmitted from the transmitter and after reflection from target, the radio signals are received by the receiver.

The time interval is recorded between the two instants i.e from time of transmission to time of reception. By knowing velocity and time, distance can be measured.

IV. Numerical Problems:

Question 1.
In a submarine equipped with sonar the time delay between the generation of a pulse and its echo after reflection form an enemy submarine is observed to be 80s. If the speed of sound in water is 1460 ms^-1. What is the distance of enemy submarine?
Solution:
Time taken = 80s
Velocity of sound = V = 1460 m/s
Distance of enemy submarine d = ?
V = \(\frac{2d}{t}\)
d = \(\frac{Vt}{2}\)
= \(\frac{1460×80}{2}\)
= 1460 x 40
= 58400 m
d = 58.4k m

Question 2.
The radius of the circle is 3.12 m calculate the area of the circle with regard to significant figures.
Solution:
Given: radius: 3.12 m (Three significant figures)
Solution:
Area of the circle = πr² = 3.14 × (3.12 m)² = 30.566
If the result is rounded off into three significant figure, the area of the circle = 30.6 m²

Question 3.
Assuming that the frequency γ of the vibrating string may depend up on
(i) applied force (F)
(ii) Length (l)
(iii) mass per unit length (m) prove that γ ∝ \(\frac { 1 }{ l }\)\(\sqrt{\frac{F}{m}}\) using dimensional analysis.
Solution:
γ ∝ F^a l^bm^c
Writing dimension on both sides

Hence Proved.

Question 4.
Jupiter is at a distance of 824.7 million Km from the earth. Its angular diameter is measured to be 35.72″ calculate the diameter of Jupiter
Solution:

Given Distance of Jupiter = 824.7 × 10⁶ km = 8.247 × 10¹¹ m
angular diameter = 35.72 × 4.85 × 10^-6rad = 173.242 × 10^-6 rad = 1.73 × 10^-4 rad
∴ Diameter of Jupiter D = D × d = 1.73 × 10^-4 rad × 8.247 × 10¹¹ m
= 14.267 × 1o⁷ m = 1.427 × 10⁸ m (or) 1.427 × 10^{5 Km}

Question 5.
The measurement value of length of a simple pendulum is 20 cm known with 2mm accuracy. The time for 50 oscillations was measured to be 40s with in Is resolution. Calculate the percentage accuracy in the determination of acceleration due to gravity g from the above statement.
Solution:
l = 20 x 10^-2m = 20 cm
∆l = 2mm = 0.2 cm
Time for 50 oscillations = 40s
Time for 1 oscillation = T = \(\frac { 40 }{ 50 }\)
= \(\frac { 4 }{ 5 }\)s
∆T = 1s.
∆T = \(\frac { 1 }{ 50 }\)S

= 1% + 5%
= 6%

11th Physics Guide Nature of Physical World and Measurement Additional Important Questions and Answers

I. Multiple choice questions:

Question 1.
The unit of surface tension ……
(a) MT^-2
(b) Nm^-2
(c) Nm
(d) Nm^-1
Answer:
(d) Nm^-1

Question 2.
One astronomical unit is equal to _______.
(a) 1.510 x 10¹²m
(b) 1.5 x 10¹²Km
(c) 1.5 x 10¹¹m
(d) 1.5 x 10¹²Cm
Answer:
(c) 1.5 x 10¹¹m

Question 3.
One light-year is ……
(a) 3.153 × 10⁷ m
(b) 1.496 × 10⁷ m
(c) 9.46 × 10¹² km
(d) 3.26 × 10¹⁵ km
Answer:
(c) 9.46 × 10¹² km

Question 4.
The dimensional formula for the coefficient of viscosity is _______.
(a) M⁰ L^-1T^-1
(b) M¹ L¹T¹
(c) M¹ L^-1T¹
(d) M² L²T⁰
Answer:
(c) M¹ L^-1T¹

Question 5.
One parsec is …..
(a) 3.153 × 10⁷ m
(b) 3.26 × 10¹⁵ m
(c) 30.84 × 10¹⁵ m
(d) 9.46 × 10¹⁵ m
Answer:
(c) 30.84 × 10¹⁵ m

Question 6.
The dimensional formula for (ε₀) permittivity of free space _______.
(a) M^-1 L³ T⁴ A²
(b) M^-1 L³ A²
(c) M^-1L^-3T⁴A²
(d) M¹L³T^-4A^-2
Answer:
(c) M^-1L^-3T⁴A²

Question 7.
One Angstrom is ………
(a) 10^-9 m
(b) 10^-10m
(c) 10^-12 m
(d) 10^-15 m
Answer:
(b) 10^-10 m

Question 8.
In the formula x = 3yz², x and y have dimensions of capacitance and magnetic induction respectively what are the dimensions of y?
(a) M³ L² T² Q⁴
(b) M³ L^-2T⁴Q⁴
(c) M³ L² T⁴ Q⁴
(d) M³L^-2T⁴Q⁴
Answer:
(d) M³L^-2T⁴Q⁴

Question 9.
\(\frac{1}{12}\) of the mass of carbon 12 atom is …..
(a) 1 TMC
(b) mass of neutron
(c) 1 amu
(d) mass of hydrogen
Answer:
(d) mass of hydrogen

Question 10.
The resistance of a conductor R = V/I where v = (50±2)v and I = (9 ± 0.3) A find the percentage error in R.
(a) 8.5%
(b) 3.7%
(c) 7.8%
(d) 7.3%
Answer:
(d) 7.3%

Question 11.
The study of forces acting on bodies whether at rest or in motion is …..
(a) classical mechanics
(b) quantum mechanics
(c) thermodynamics
(d) condensed matter physics
Answer:
(a) classical mechanics

Question 12.
In the measurement of pressure if maximum errors in the measurement of force and length of a square plate are 3% and 2% respectively. The maximum error is _______.
(a) 7%
(b) 8%
(c) 4%
(d) 5%
Answer:
(a) 7%

Question 13.
Which of the following is not a dimensionless physical quantity?
(a) Mechanical equivalent of heat
(b) volumetric strain
(c) atomic mass unit
(d) Avogadro’s number
Answer:
(c) atomic mass unit

Question 14.
The study of production and propagation of sound waves …..
(a) Astrophysics
(b) Acoustics
(c) Relativity
(d) Atomic physics
Answer:
(b) Acoustics

Question 15.
The physical quantities not having the same dimensions are _______.
(a) torque and work
(b) Linear momentum and planks constant
(c) stress and youngs modulus
(d) speed and (ε₀μ₀)^-1/2
Answer:
(a) torque and work

Question 16.
Which two of the following five physical parameters have the same dimension?
(1) energy density
(2) refractive index
(3) dielectric content
(4) youngs modulus
(5) magnetic field

(a) 1 and 4
(b) 1 and 5
(c) 2 and 4
(d) 3 and 5
Answer:
(a) 1 and 4

Question 17.
The astronomers used to observe distant points of the universe by …….
(a) Electron telescope
(b) Astronomical telescope
(c) Radio telescope
(d) Radar
Answer:
(c) Radio telescope

Question 18.
The youngs modulus of a material of the wire is 12.6 x 10¹¹ dyne/cm². Its value is MKS system is _______.
(a) 12.6 x 10¹² N/M²
(b) 12.6 x 10¹⁰ N/M²
(c) 12.6 x 10⁶ N/M²
(d) 12.6 x 10⁸ N/M²
Answer:
(a) 12.6 x 10¹² N/M²

Question 19.
The dimensionless quantity _______.
(a) never has a unit
(b) always has a unit
(c) may has a unit
(d) does not exist
Answer:
(c) may has a unit

Question 20.
Which one of the following is not a fundamental quantity?
(a) length
(b) luminous intensity
(c) temperature
(d) water current
Answer:
(d) water current

Question 21.
The time dependence of a physical quantity p is givers by \(p_{0} e^{-\alpha t^{2}}\) = P, where α is a constant and t is time. The constant α is _______
(a) a dimensionless
(b) has the dimension of T²
(c) has the dimension as that of P
(d) has the dimension equal to dimensions of PT^-2
Answer:
(a) a dimensionless

Question 22.
A force F is given F = at + bt² Where t is time. What are the dimensions of a & b?
(a) ML T^-3 and ML²T^-4
(b) MLT^-3 and MLT^-4
(c) MLT^-1 and MLT⁰
(d) MLT^-4and MLT^-1
Answer:
(a) ML T^-3 and ML²T^-4

Question 23.
The triple point temperature of the water is ……
(a) -273.16 K
(b) 0K
(c) 273.16 K
(d) 100 K
Answer:
(d) 100 K

Question 24.
The force F on a sphere of radius ‘a’ moving in a medium with a velocity v is given by F = 6 π av. The dimension of η are
(a) ML^-1T^-2
(b) MT^-1
(c) MLT^-2
(d) ML^-3
Answer:
(d) ML^-3

Question 25.
The unit of moment of force ……
(a) Nm²
(b) Nm
(c) N
(d) NJ rad
Answer:
(b) Nm

Question 26.
If the orbital velocity of a planet is given by v = G^aM^bR^c then _______.
(a) a = 1/3, b = 1/3, c = – 1/3
(b) a = 1/2, b =1/2, c = – 1/2
(c) a = 1/3, b = – 1/2, c = 1/2
(d) a = 1/2, b = – 1/2, c = – 1/2
Answer:
(a) a = 1/3, b = 1/3, c = – 1/3

Question 27.
The period T of a soap bubble under SHM given by T = P^aD^bS^c where P is the pressure, d is the density of water and E is the total energy of the explosion, then the value of a, b and c are:
(a) -3/2, 1/2, 1
(b) -5/6, 1/2, 1/3
(c) 5/6, 1/2, 1/3
(d) -5/6, -1/2, 1/3
Answer:
(a) -3/2, 1/2, 1

Question 28.
One degree of arc is equal to …….
(a) 1.457 × 10² rad
(b) 1.457 × 10^-2 rad
(c) 1.745 × 10² rad
(d) 1.745 × 10^-2 rad
Answer:
(b) 1.457 × 10^-2 rad

Question 29.
Frequency is the functions of density p length ‘l’ and tension T. The period of oscillation is proportional to _______.
(a) ρ^1/2 λ² T^-1/2
(b) ρ^1/2 λ^3/2T^-1/2
(c) ρ^1/2 λ^3/2 T^-3/4
(d) ρ^1/2 λ^1/2 T^3/2
Answer:
(a) ρ^1/2 λ² T^-1/2

Question 30.
The frequency of vibration of string is given by γ^l = \(\frac{p}{2 \ell} \sqrt{\frac{T}{m}}\) Here l is the length, P is the number of segments in the string. T is tension is the string, the dimensional formula for ‘m’ will be.
(a) M⁰ L T^-1
(b) M L⁰ T^-1
(c) M L^-1 T⁰
(d) M⁰ L⁰ T⁰
Answer:
(c) M L^-1 T⁰

Question 31.
1 second of arc is equal to ………………..
(a) 0.00027°
(b) 1.745 × 10^-2 rad
(c) 2.91 × 10^-4 rad
(d) 4.85 × 10^-6 rad
Answer:
(a) 0.00027°

Question 32.
If force (f), length (L) and time (T) are assumed to be fundamental units then the dimensional formula of the mass will be _______.
(a) FL^-1T²
(b) FL^-1T²
(c) FL^-1 T^-1
(d) FL²T²
Answer:
(a) FL^-1T²

Question 33.
If pressure ‘p’ velocity v and time T are taken as fundamental physical quantities the dimensional formula for force is _______.
(a) [PV² T²]
(b) [P^-1V²T^-2]
(c) [PV T²]
(d) [P^-1V T²]
Answer:
(a) [PV² T²]

Question 34.
The range of distance can be measured by using direct methods is …..
(a) 10^-2 to 10^-5 m
(b) 10^-2 to 10² m
(c) 10² to 1(T5 m {d) 10″2 to 105 m
Answer:
(b) 10^-2 to 10² m

Question 35.
The speed of light (c) gravitational constant G and planks constant h are taken as fundamental units. The dimension of time in the new system will be _______.
(a) G^1/2 h^1/2 C^-5/2
(b) g^1/2 h^1/2 C^1/2
(c) G^1/2 h^1/2 C^-3/2
(d) G^1/2 h^1/2 C^1/2
Answer:
(a) G^1/2 h^1/2 C^-5/2

Question 36.
The rate of flow(Q) (volume of liquid flowing per unit volume through a pipe depends on radius r, Length f of pipe, pressure difference P across the ends of pipe and coefficient of viscosity of liquid η as Q α r^aρ^b η^cL^dthen _______
(a) a = 4, b = 1, c = – 1, d = – 1
(b) a = 4, b = – 1, c = 1, d = – 1
(c) a = 4, b = 1, c = 1, d = – 1
(d) values of a,b,c and d cannot be determined
Answer:
(d) values of a,b,c and d cannot be determined

Question 37.
The dimensions of universal gas constant is _______
(a) ML²T^-2θ^-1
(b) ML²T^-2θ
(c) ML³ T^-1 θ^-1
(d) none of these
Answer:
(a) ML²T^-2θ^-1

Question 38.
Find odd one out.
(a) Newton
(b) metre
(c) candela
(d) Kelvin
Answer:
(a) Newton

Question 39.
Which of the following combinations have the dimensions of time? L, C, R represent inductance, capacitance, and resistance respectively.
(a) RC
(b) \(\sqrt{LC}\)
(c) L/R
(d) C/L
Answer:
(b) \(\sqrt{LC}\)

Question 40.
The dimensions of mobility are _______
(a) M^-1 LA T^-2
(b) ML A^-1T^-2
(c) MA^-1T^-2
(d) M^-1A T²
Answer:
(d) M^-1A T²

Question 41.
The smallest physical unit of time is
(a) second
(b) minute
(c) microsecond
(d) shake
Answer:
(d) shake

Question 42.
The length, breadth and thickness of strip are given by l = (10.0±0.1)cm, h=(1.00±0.01)cm t = (0.100±0.001)cm the most probable error in volume will be _______
(a) 0.03 cm³
(b) 0.111 cm³
(c) 0.012 cm³
(d) 0.12 cm³
Answer:
(a) 0.03 cm³

Question 43.
The measured mass and volume of a body are 22.42g and 4.7cm³ respectively with possible errors of 0.01 g and 0.1cm³. The maximum error in density is _______.
(a) 0.2%
(b) 2%
(c) 5%
(d) 10%
Answer:
(b) 2%

Question 44.
Half the lifetime of a free neutron is in the order of ……
(a) 10°
(b) 10¹ s
(c) 10² s
(d) 10³ s
Answer:
(d) 10³ s

Question 45.
An experiment measures quantities a, b, c and y is calculated from a formula. y = \(\frac{a b^{2}}{c^{3}}\) If the percentage errors in a,b and c are ± 1%, ± 3%, ± 2% respectively, the percentage error in calculating y is _______
(a) ± 13%
(b) ± 7%
(c) ±4%
(d) ± 1%
Answer:
(a) ± 13%

Question 46.
A student measures the distance traversed in a free fail of a body, initially at rest in a given time. He uses this data to estimate g, the acceleration due to gravity. If maximum percentage error in measurement of the distance and the time are e₁ and e₂ respectively the percentage error in the estimation of g is _______
(a) e₂ – e₁
(b) e₁+ 2e₂
(c) e₁ + e₂
(d) e₁ – 2e₂
Answer:
(b) e₁+ 2e₂

Question 47.
The heat generated in a circuit is given by Q = I²Rt. Where I is current, R is the resistance and t is the time. If an error in measuring current, resistance, and time are 2%, 1%, and 1% respectively. The maximum error in measuring heat will be _______
(a) 2%
(b) 4%
(c) 6%
(d) 8%
Answer:
(c) 6%

Question 48.
Imperfections in experimental procedure give ……………….. error.
(a) random
(b) gross
(c) systematic
(d) personal
Answer:
(c) Systematic

Question 49.
A student performs an experiment for determination of g = \(\frac{4 \pi^{2} l}{T^{2}}\) an error of ∆l. For that, he takes the time of n oscillations with the stopwatch of least count ∆T and he commits a human error of 0.1s. For which of the following data, the measurement of g will be most accurate? ∆l, ∆T, n
(a) 5m, 0.2s, 10
(b) 5mm, 0.2s, 20
(c) 5mm, 0.1s, 20
(d) 1mm, 0.1s, 50
Answer:
(d) 1mm, 0.1s, 50

Question 50.
A Screw gauge gives the following reading when used to measure the diameter of the wire.
Main scale reading = 0.
Circular scale reading = 52 divisions
Given that 1 mm on the main scale corresponds to 100 division on a circular scale. The diameter of the wire is _______.
(a) 0.52 cm
(b) 0.052 cm
(c) 0.0026 cm
(d) 0.005 cm
Answer:
(b) 0.052 cm

Question 51.
The error caused due to the sheer carelessness of an observer is called as ……………. error.
(a) Systematise
(b) Gross
(c) Random
(d) Personal
Answer:
(b) Gross

Question 52.
The force (F) velocity(v) and time “T” are taken as fundamental units then the divisions of mass are _______.
(a) [FVT²]
(b) [FV^-1T^-1]
(c) [FV T^-1]
(d) [FV^-1T]
Answer:
(d) [FV^-1T]

Question 53.
Attempting to explain diverse physical phenomenon with few concepts and law is _______.
(a) unification (or) reductionism
(b) neither unification nor reductionism
(c) unification
(d) reductionism
Answer:
(c) unification

Question 54.
An attempt to explain a microscopic system in terms of its microscopic constituents _______.
(a) unification
(b) reductionism
(c) neither unification or reductionism
(d) neither unification nor reductionism
Answer:
(b) reductionism

Question 55.
The study of nature of particles is _______ a branch of physics.
(a) nuclear physics
(b) quantum mechanics
(c) condensed another physics
(d) high energy physics
Answer:
(d) high energy physics

Question 56.
The ratio of the mean absolute error to the mean value is called …………….
(a) absolute error
(b) random error
(c) relative error
(d) percentage error
Answer:
(c) Relative error

Question 57.
1″ is equal to _______ radian.
(a) 1.745 x 10^-2 rad
(b) 1.78 x 10^-3 rad
(c) 2.91 x 10^-4 rad
(d) 4.847 x 10^-6 rad
Answer:
(d) 4.847 x 10^-6 rad

Question 58.
From a point on the ground, the top of a tree is seen to have an angle of elevation of 60°. The distance between the tree and a point is 50 m. The height of the tree is _______.
(a) 86.6 m
(b) 90.6 m
(c) 92.8 m
(d) 80.6 m
Answer:
(a) 86.6 m

Question 59.
The maximum possible error in the sum of two quantities is equal to …….
(a) Z = A + B
(b) ∆Z = ∆A + ∆B
(c) ∆Z = ∆A/∆B
(d) ∆Z = ∆A – ∆B
Answer:
(b) ∆Z = ∆A + ∆B

Question 60.
Number of a significant digit in 0.030400
(a) 6
(b) 5
(c) 4
(d) 3
Answer:
(b) 5

II. Short Answer Type Questions:

Question 1.
A new unit of length is chosen such that the speed of light in a vacuum is unity. What is the distance between the sun and the earth in terms of the new unit if light takes 8 min and 20 s to cover this distance?
Answer:
Speed of light in vacuum, c = 1 new unit of length s^-1
t = 8 min. 20 sec, = 500 s
x = ct= 1 new unit of length s^-1 × 500s
x = 500 new unit of length

Conceptual Questions:

Question 1.
Why it is convenient to express the distance of stars in terms of light-year (or) parsec rather than in Km?
Solution:
One light-year = 9.46 x 10¹⁵ m = 9.46 x 10¹² Km. As the distance of stars is extraordinarily large, so it is convenient to express them in light-year rather than in meters or in kilometers.

Question 2.
Show that a screw gauge of pitch 1 mm and 100 divisions is more precise than a vernier caliper with 20 divisions on the sliding scale.
Solution:
The device that has a minimum least count is said to be more precise.
In case of screw gauge: Least count

= 0.05 mm
Out of this screw, gauges is having the minimum least count. So screw gauge is more precise.

Question 3.
What is the difference between mN, Nm, and nm?
Answer:
mN means milli newton, 1 mN = 10^-3 N, Nm means Newton meter, nm means nanometer.

Question 4.
Having all units in atomic standards is more useful. Explain.
Answer:
It became necessary to redefine all units in atomic standards because the prototype offers the following difficulties.

1. It is difficult to preserve prototype models.
2. It is difficult to produce replicas of prototypes for their use in different countries.
3. The techniques used for producing replicas are not of very high accuracy.
4. Atomic standard units can be reproduced anywhere and at any time.
5. It is variant in time and space.
6. It is unaffected by environmental conditions like temperature, pressure, etc.
7. It has an accuracy of 1 part in 10⁹.

Question 5.
Why dimensional methods are applicable only up to three quantities?
Answer:
The dimensional analysis is not applicable on more than 3 physical quantities because the equating powers of M, L & T, we get three unknowns. Similar constraints are present for electrical or other non-mechanical quantities also

Tamilnadu State Board New Syllabus Samacheer Kalvi 11th Commerce Guide Pdf Chapter 3 Classification of Business Activities Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 11th Commerce Solutions Chapter 3 Classification of Business Activities

11th Commerce Guide Classification of Business Activities Text Book Back Questions and Answers

I. Choose the Correct Answer.

Question 1.
The industries engaged in extraction of iron ore are known as ………………
a. Construction Industries
b. Manufacturing Industries
c. Extraction Industries
d. Genetic Industries
Answer:
c. Extraction Industries

Question 2.
Auxiliaries to trade is also called as ……………
a. Trade
b. Advertisement
c. Warehousing
d. Aids to Trade
Answer:
d. Aids to Trade

Question 3.
Production which involves several stages for manufacturing finished products is known as …………………..
a. Analytical Industry
b. Synthetic Industry
c. Processing Industry
d. None of the above
Answer:
c. Processing Industry

Question 4.
Normally high level risk involved in ……………….
a. Industry
b. Commerce
c. Trade
d. All of the above
Answer:
a. Industry

Question 5.
Commerce is mainly concerned with ………………….
a. Connecting producer and consumer
b. Pricing of Goods
c. Buying and Selling of goods
d. Manufacturing of goods
Answer:
a. Connecting producer and consumer

II. Very Short Answer Questions

Question 1.
Define commerce:
Answer:
According to Evelyn Thomas, “Commercial operations deal with the buying and selling of goods, the exchange of commodities and the contribution of finished products”.

Question 2.
What do mean by industry?
Answer:
Industry refers to economic activities which are connected with conversion of resources into useful goods. The term is used for activities in which mechanical appliances and technical skills are involved. E.g Electronic industry would include all firms producing electronic goods, and so on.

Question 3.
What is trade?
Answer:
The term ‘trade’ is used to denote buying and selling. It is an essential part of commerce.

Question 4.
Write a short note on transportation.
Answer:
Transport or transportation is the medium which helps the movement of humans, animals and goods from one location to another. Since all the goods produced cannot be consumed in the place of production, it should be move to the places where they are demanded. The process of moving goods is known an transportation.

III. Short Answer Questions

Question 1.
Distinguish between Extractive industries and genetic industries.
Answer:
Extractive industries:

• These industries extract or draw out products from natural sources.
• Extractive industries supply some basic raw materials that are mostly products of the geographical or natural environment.

Genetic industries:

• These industries remain engaged in breeding plants and animals for their use in further reproduction.
• The seeds, nursery companies poultry, dairy, piggery, hatcheries, nursery, fisheries, apiary etc.

Question 2.
What do you mean by tertiary industries?
Answer:
The industries which produces utility services and sell them at the profit. These industries help trade, commerce and industry. The auxiliaries to trade like banking, insurance, warehouse, advertisement etc. are included in this.

Question 3.
Write any three characteristics of commerce.
Answer:
1. Economic Activity: Commerce is an economic activity because it consists of activities which are undertaken for earning profits. A trader buys goods with the aim of selling them at a profit.

2. Exchange of Goods and Services: Commerce involves the exchange and distribution of goods and services. Goods may be purchased or produced for sale. Commerce comprises both trade and aids to trade.

3. Profit Motive: The motive of commercial activities is to earn profits. Any activity which does not have the aim of profit will not be a part of commerce.

Question 4.
Narrate commerce with an example.
Answer:
Commerce includes all the activities which help in bringing goods from the producer to the’ ultimate consumer. According to Evelyn Thomas, “Commercial operations deal with the buying and selling of goods, the exchange of commodities and the contribution of finished products”. Commerce includes services such as transport, warehousing, packaging, insurance, banking and sales promotion which are incidental or auxiliaries to trade.

IV. Long Answer Questions

Question 1.
Explain the various kinds of industries on the basis of size.
Answer:
1. Micro Units: A unit wherein investment in plant and machinery is upto Rs. 25 lakhs in case of manufacturing and upto Rs. 10 lakhs in case of service enterprises.

2. Small Units: A manufacturing unit wherein investment in plant and machinery is more than Rs. 25 lakhs but does not exceed Rs.5 crore. In the case of service enterprises, these limits are Rs. 10 lakhs and Rs. 2 crores respectively.

3. Medium Units: A manufacturing unit wherein investment in plant and machinery is more than Rs.5 crore but does not exceed Rs. 10 crore. In the case of service enterprises, these limits are Rs.2 crore and Rs.5 crore respectively.

4. Large Units: A manufacturing unit wherein, investment in plant and machinery exceeds Rs.10 crore. In the case of a service unit investment in equipment exceeds Rs.5 crore.

Question 2.
Compare industry, commerce, and trade.
Answer:

SI. No	Variables	Industry	Commerce	Trade
1.	Meaning	Extraction,reproduction,conversion, processing and construction of useful products	Activities involving the distribution of goods and services	Purchase and sales of goods and services
2.	Scope	Consists of all activities involving conversion of material and semi-finished into finished goods.	Comprises trade auxiliaries to trade	Comprises exchange of good. and services
3.	Capital	a large amount of capital is required	Need for capital is comparatively less	Small capital is needed to maintain stock and to grant credit
4.	Risk	High risk is involved	Relatively less risk is involved	Relatively less risk is involved
5.	Side	It represents the supply side of goods and services	It represents the demand side of goods and services	It represents both supply and demand
6.	Utility creation	It creates form utility by changing the form or shape of materials	It creates place utility by moving goods from producers to consumers	It creates possession utility through exchange.

Question 3.
What are the characteristics of commerce?
Answer:
1. Economic Activity:
Commerce is an economic activity because it consists of activities which are undertaken for earning profits. A trader buys goods with the aim of selling them at a profit.

2. Exchange of Goods and Services:
Commerce involves the exchange and distribution of goods and services. Goods may be purchased or produced for sale. Commerce comprises both trade and aids to trade.

3. Profit Motive:
The motive of commercial activities is to earn profits. Any activity which does not have the aim of profit will not be a part of commerce.

4. Regularity of Transaction:
An isolated transaction does not imply commerce.

5. Creation of Utilities:
Commerce creates several types of utilities. It creates place utility by carrying goods to the place where they are needed. It makes goods available as and when demanded thereby creating time utility. By creating these utilities commerce helps to increase the volume of trade.

Question 4.
Write short notes on:

1. Analytical industry
2. Genetic industry and
3. Construction industry.

Answer:
1. Analytical industry:
These industries are called Secondary industries. These industries analyses and separates different elements from the same material, as in the case of oil refinery. In these industries the raw material is broken down into several useful materials.
E.g an oil industry separates crude oil into keroseñe, gasóline, diesel oil and petrol etc.

2. Genetic Industry:
The word ‘Genetic’ means parentage or hereditary. Genetic industries are concerned mainly with producing  breeding or multiplying of certain species of plants or animals with the object of earning profits from their sale. Examples of these types are nurseries, forestry, cattle-breeding, and commercial kennels. Animal husbandry is one type of Genetic Industry.

3. Construction Industry:
These industries are involved in the construction of building, dams, bridges, roads as well as tunnels and canals.

Question 5.
Briefly explain the auxiliaries to trade.
Answer:
Meaning:

Auxiliaries of trade may be classified into five categories:
1. Transportation:
Selling all the goods produced at or near the production place is not possible. Hence, goods are to be sent to different places where they are demanded.

2. Banking and Finance:
Nowadays we cannot think of a business without a bank. A bank is an organization which accepts deposits of money from the public, withdrawals on demand or otherwise, and lends the same to those who need it. Necessary funds can be obtained by businessmen from a bank. Thus, banking helps business activities to overcome the v problem of finance.

3. Insurance:
Business involves various types of risks. Materials and goods held in stock or in transit are subject to the risk of loss or damage. Insurance provides protection in all such cases. On payment of a nominal premium, the amount of loss or damage and compensation for an injury, if any, can be recovered from the insurance company.

4. Warehousing:
Goods are held in stock to make them available as and when required. Special arrangements must be made for the storage of goods to prevent loss or damage. Warehousing helps business firms to overcome the problem of storage and facilities the availability of goods when needed.

5. Advertising:
Advertising is one of the most important methods of promoting the sale of products, particularly, consumer goods like electronic goods, automobiles, soaps, detergents, etc. Advertising helps in providing information about available goods and services and inducing customers to buy particular items.

11th Commerce Guide Classification of Business Activities Additional Important Questions and Answers

I. Choose the Correct Answer:

Question 1.
All business activities can be classified into ……………. broad categories.
(a) Two
(b) Three
(c) Four
(d) Five
Answer:
(a) Two

Question 2.
Manufacturing industries may be categorized into ………………
a) Two
b) Three
c) Four
d) Ten
Answer:
c) Four

Question 3.
Horticulture is an example for …………….
(a) Primary industry
(b) Secondary industry
(c) Tertiary industry
(d) Local industry
Answer:
(a) Primary industry

Question 4.
…………………. industries produce utility services and sell them at a profit.
a) Construction Industries
b) Tertiary Industries
c) Analytical Industries
d) Manufacturing Industries
Answer:
b) Tertiary Industries

Question 5.
Professional or specialized skills and high technology are used to provide ……………. type of services.
(a) Personalised
(b) Public
(c) Distributive
(d) Quaternary
Answer:
(d) Quaternary

Question 6.
Expand MSME:
a) Major Small Medium Enterprises
b) Micro Scale. Middle Enterprises
c) Micro Small Medium Enterprises
d) Medium Small Micro Enterprises
Answer:
c) Micro Small Medium Enterprises

Question 7.
The service Enterprises with a maximum investment of 5 crores Is known as …………
a) Micro Unit
b) Small Unit
c) Large Unit
d) Medium Unit
Answer:
d) Medium Unit

Question 8.
Special arrangements must be made for goods to prevent loss or damage.
(a) Transportation
(b) Pricing
(c) Storage
(d) Advertising
Answer:
(c) Storage

Question 9.
Which of the following is not categorized as commerce?
a) Buy goods with ‘the aim of selling at profit.
b Exchange and Distribution of goods and services.
c) An individual sells his asset.
d) None of the above.
Answer:
c) An individual sells his asset.

Question 10.
Auxiliaries of trade are also called……………………
a) Trade
b) Advertisement
c) Warehousing
d) Aids to trade
Answer:
d) Aids to trade

Question 11.
The production which Involves several stages for manufacturing finished products Is known as………….
a) Analytical Industry
b) Synthetic Industry
c) Processing Industry
d) None of the above
Answer:
c) Processing Industry

Question 12.
Normally high-level risk involved in ………………….
a) Industry
b) Commerce
c) Trade
d) All the above
Answer:
a) Industry

Question 13.
Commerce is mainly concerned with
a) Distribution of Goods
b) Pricing of Goods
c) Buying and Selling of Goods
d) Manufacturing of Goods
Answer:
b) Pricing of Goods

II. Very Short Answer Questions

Question 1.
What is the Extractive industry?
Answer:
Extractive industries extract or draw out products from natural sources. Extractive industries supply some basic raw materials that are mostly products of the geographical or natural environment.

Question 2.
What do you mean by Tertiary Industries?
Answer:
The industry which produces utility services and sells them at a profit is known as tertiary industries:
They do not produce goods. They help in trade, industry, and commerce. It is also known as the Service industry.
E.g: The tourism and Hospitality industry, banking industries, etc.

Question 3.
What is the Secondary industry?
Answer:
Secondary Industries are concerned with using the materials which have already been extracted at the primary stage. These industries process such materials to produce goods for final consumption or for further processing by other industrial units.

III. Short Answer Questions.

Question 1.
Write any three categories of Manufacturing industries.
Answer:

1. Analytical Industry analyses and separates different elements from the same materials, as in the case of an oil refinery.
2. The synthetic Industry combines various ingredients into a new product, as in the case of cement.
3. The processing Industry involves successive stages for manufacturing finished products, as in the case of sugar and paper.

IV. Long Answer Questions

Question 1.
Write short notes on Primary Industries.
Answer:
These industries concerned with the production of goods with the help of nature. It is a nature-oriented industry, which requires very little human effort, for example, Agriculture, farming, forestry, fishing, horticulture, etc.
These industries are subdivided as follows:

Extractive Industries:
These industries extract or draw out products from natural resources. These industries supply some basic raw materials that are mostly products of the geographical or natural environment. These products are transformed into other manufacturing industries. These industries include farming, mining, lumbering, hunting and fishing operations.

Genetic Industries:
These industries engaged in breeding plants and animals for their use in further reproduction. The seeds, nursery companies, poultry, dairy, piggery, hatcheries, nursery, fisheries, apiary, etc are some of the examples of genetic industries.

Question 2.
Write a short note on Secondary Industries.
Answer:
These industries produced goods for final, consumption or for further processing by other industrial units. For example, the mining of iron ore is a primary industry, but the manufacturing of steel is a secondary industry.

It can be categorized as follows:

• Manufacturing Industries: These industries are engaged in producing goods through the processing of raw materials and thus creating from utilities. These industries may be further divided into four categories on the basis of the method of Operation for production.
• Analytical Industry: Which analyses and separates different elements from the same materials, as in the case of an oil refinery.
• Synthetically Industry: Which combines various ingredients into new products, as in the case of cement.
• Processing Industry: Which involves successive stages for manufacturing finished products, as in the case of sugar and paper.
• Assembling Industry: Which assembles different component parts to make a new product, as in the case of television, car, computer, etc.
• Construction Industries: These industries are involved in the construction of buildings, dams, bridges, roads as well as tunnels and canals.

Question 3.
Write a note on Tertiary industries.
Answer:
The industries which produce utility services and sell them at the profit. These industries help trade, commerce, and industry. The auxiliaries to trade like banking, insurance, warehouse, advertisement, etc are included in this. These industries are further classified as under:

• Personalized service: The individuals and private institutions selling their services to others is called personalized services. E.g Plumber, servant maid, etc.
• Public service: The government provides services to the people without profit motive through Government hospitals, schools, police, government offices, etc.
• Distributive service: Transportation, sales, warehousing, logistics, salesmanship, etc. come under this type of service.
• Financial service: Banking, factoring, accounting, and insurance, etc. are grouped under this type of service.
• Quaternary service: Professional or specialized skills and high technology are used to provide this type of service. E.g. Software development, Auditing, Research, and Development, etc.
• Quinary service: Selective individual experts create new ideas, implement new technologies and implement new policies. These decisions influenced the growth and development of national and international institutions.

Tamilnadu State Board New Syllabus Samacheer Kalvi 12th Computer Science Guide Pdf Chapter 11 Database Concepts Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 12th Computer Science Solutions Chapter 11 Database Concepts

12th Computer Science Guide Database Concepts Text Book Questions and Answers

I. Choose the best answer (1 Marks)

Question 1.
What is the acronym of DBMS?
a) Data Base Management Symbol
b) Database Managing System
c) Data Base Management System
d) DataBasic Management System
Answer:
c) Data Base Management System

Question 2.
A table is known as
a) tuple
b) attribute
c) relation
d) entity
Answer:
c) relation

Question 3.
Which database model represents parent-child relationship?
a) Relational
b) Network
c) Hierarchical
d) Object
Answer:
c) Hierarchical

Question 4.
Relational database model was first proposed by
a) E F Codd
b) E E Codd
c) E F Cadd
d) E F Codder
Answer:
a) E F Codd

Question 5.
What type of relationship does hierarchical model represents?
a) one-to-one
b) one-to-many
c) many-to-one
d) many-to-many
Answer:
b) one-to-many

Question 6.
Who is called Father of Relational Database from the following?
a) Chris Date
b) Hugh Darween
c) Edgar Frank Codd
d) Edgar Frank Cadd
Answer:
c) Edgar Frank Codd

Question 7.
Which of the following is an RDBMS?
a) Dbase
b) Foxpro
c) Microsoft Access
d) SQLite
Answer:
d) SQLite

Question 8.
What symbol is used for SELECT statement?
a) o
b) n
c) X
d) Q
Answer:
a) o

Question 9.
A tuple is also known as
a) table
b) row
c) attribute
d) field
Answer:
b) row

Question 10.
Who developed ER model?
a) Chen
b) EF Codd
c) Chend
d) Chand
Answer:
a) Chen

II. Answer the following questions (2 Marks)

Question 1.
Mention few examples of a database.
Answer:
dbase-III , dbase-III Plus, Foxbase , Foxpro ,SQL Server, Oracle Database, Sybase, Informix, MySQL are some examples of Database languages which are used to design ERP applications like Payroll, Railway Reservation System, Inventory Systems.

Question 2.
List some examples of RDBMS.
Answer:
SQL Server, Oracle Database, Sybase, Informix, MySQL.

Question 3.
What is data consistency?
Answer:
Data Consistency
On live data, it is being continuously updated and added, maintaining the consistency of data can become a challenge. But DBMS handles it by itself. Data Consistency means that data values are the same at all instances of a database.

Question 4.
What is the difference between the Hierarchical and Network data model?
Answer:

Hierarchical Data Model		Network Data Model
1	A child record has only one parent node	A child may have many parent nodes
2	It represents the data in one-to-many relationships	It represents the data in many-to-many relationships
3	This model is not easier and faster to access the data than the Network data model.	This model is easier and faster to access the data.

Question 5.
What is normalization?
Answer:

• Normalization is a process of organizing the data in the database to avoid data redundancy and to improve data integrity.
• Database normalization was first proposed by Dr. Edgar F Codd as an integral part of RDBMS. These rules are known as the E F Codd Rules.

III. Answer the following questions (3 Marks)

Question 1.
What is the difference between Select and Project
Answer:

Select	Project
The SELECT operation(o) is used for selecting a subset with tuples according to a given selection condition.	The projection method(n) eliminates all attributes of the input relation but those mentioned in the projection list.
The SELECT operation (o) selects filters out all tuples that do not satisfy the condition.	The projection method defines a relation that contains a vertical subset of Relation.
Symbol: σ	Symbol: π
General Form: σ (R) c Example: σ = “Big Data” (STUDENT) course	Example: π  (STUDENT) course

Question 2.
What is the role of DBA?
Answer:

1. Database Administrator or DBA is the one who manages the complete database management system.
2. DBA takes care of the security of the DBMS, managing the license keys, managing user accounts and access etc.

Question 3.
Explain Cartesian Product with a suitable example.
Answer:

• Cross product is a way of combining two relations.
• The resulting relation contains, both relations being combined.
• A x B means A times B, where the relation A and B have different attributes.
• This type of operation is helpful to merge columns from two relations

studno	name	studno	subject
cs1	Kannan	cs28	Big Data
cs2	Gowri Shankar	cs62	R language
cs4	Padmaja	cs25	Python Programming

Cartesian product; Table A x Table B

studno	name	course	subject
cs1	Kannan	cs28	Big Data
cs1	Kannan	cs62	. R language
cs1	Kannan	cs25	Python Programming
cs2	Gowri Shankar	cs28	Big Data
cs2	Gowri Shankar	cs’62	R language
cs2	Gowri Shankar	cs25	Python Programming
cs4	Padmaja	cs28	Big Data
cs4	Padmaja	cs62	R language
cs4	Padmaja	cs25	Python Programming

Question 4.
Explain the Object Model with an example.
Answer:
Object Model:

• Object model stores the data in the form of objects, attributes and methods, classes and inheritance.
• This model handles more complex applications, such as Geographic Information System (GIS), scientific experiments, engineering design and manufacturing.
• It is used in file Management System.
• It represents real-world objects, attributes and behaviours.
• It provides a clear modular structure.
• It is easy to maintain and modify the existing code.

An example of the Object model is : Shape

Circle, Rectangle, and Triangle are all objects in this model

• The circle has the attribute radius.
• Rectangle has the length and breadth of the attribute.
• Triangle has the attributes base and height.
• The objects Circle, Rectangle, and Triangle inherit from the object Shape.

Question 5.
Write a note on different types of DBMS users.
Answer:
Types of DBMS Users
(i) Database Administrator:
Database Administrator or DBA is the one who manages the complete database management system. DBA takes care of the security of the DBMS, managing the license keys, managing user accounts and access etc.

(ii) Application Programmers or Software Developers:
This user group is involved in developing and designing the parts of DBMS.

(iii) End User:
End users are the ones who stores, retrieve, update and delete data.

(iv) Database designers: are responsible for identifying the data to be stored in the database for choosing appropriate structures to represent and store the data.

IV. Answer the following questions (5 Marks)

Question 1.
Explain the different types of data models.
Answer:
The different types of a Data Model are:

1. Hierarchical Model,
2. Relational Model,
3. Network Database Model,
4. Entity-Relationship Model,
5. Object Model.

Hierarchical Model:

• The hierarchical model was developed by IBM as Information Management System.
• In the Hierarchical model, data is represented as a simple tree-like structure form.
• This model represents a one-to-many relationship i.e., parent-child relationship.
• One child can have only one parent but one parent can have many children.
• This model is mainly used in IBM Main Frame computers.

Relational Model:

• The Relational Database model was first proposed by E.F. Codd in 1970.
• Nowadays, it is the most widespread data model used for database applications around the world.
• The basic structure of data in the relational model is tabling (relations).
• All the information related to a particular type is stored in rows of that table.
• Hence tables are also known as relations in a relational model.
• A relation key is an attribute that uniquely identifies a particular tuple (row in a relation (table)).

Network Model:
A network database model is an extended form of the hierarchical data model.
The difference between hierarchical and Network data model is:

• In a hierarchical model, a child record has only one parent node,
• In a Network model, a child may have many parent nodes.
• It represents the data in many-to-many relationships.
• This model is easier and faster to access the data.

Example:

• School represents the parent node
• Library, Office, and Staffroom is a child to school (parent node)
• Student is a child in the library, office and staff room (one to many relationships)

Entity-Relationship Model. (ER model):

• In this database model, relationships are created by dividing the object into the entity and its characteristics into attributes.
• It was developed by Chen in 1976.
• This model is useful in developing a conceptual design for the database.
• It is very simple and easy to design a logical view of data.
• The developer can easily understand the system by looking at ER model constructed.
• The rectangle represents the entities.

Example. Doctor and Patient.

• Ellipse represents the attributes
  E.g. D-id, D-name, P-id, P-name.
• Attributes describe the characteristics and each entity becomes a major part of the data stored in the database.
• The diamond represents the relationship in ER diagrams e.g; Doctor diagnosis the Patient

Object Model:

• Object model stores the data in the form of objects, attributes, and methods, classes, and Inheritance.
• This model handles more complex applications, such as Geographic Information System (GIS), scientific experiments, engineering design, and manufacturing.
• It is used in the file Management System.
• It represents real-world objects, attributes, and behaviours.
• It provides a clear modular structure. It is easy to maintain and modify the existing code.

Example of the Object model is Shape,
Circle, Rectangle and Triangle are all objects in this model

• The circle has the attribute radius.
• Rectangle has the length and breadth of the attribute.
• Triangle has the attributes base and height.
• The objects Circle, Rectangle, and Triangle inherit from the object Shape.

Question 2.
Explain the different types of relationship mapping.
Answer:
The types of relationships used in a database are

• One-to-One Relationship
• One-to-Many Relationship
• Many-to-One Relationship
• Many-to-Many Relationship

One-to-One Relationship:

• In One-to-One Relationship, one entity is related with only one other entity.
• One row in a table is linked with only one row in another table and vice versa. Example: A student can have only one exam number.

One-to-Many Relationship:

• In a One-to-Many relationship, one entity is related to many other entities.
• One row in table A is linked to many rows in table B, but one row in table B is linked to only one row in table A. Example: One Department has many staff members.

Many to-one Relationship

• In Many-to-One Relationship, many entities can be related with only one in the other entity.
• Example: A number of staff members working in one Department. Multiple rows in staff members table is related with only one row in Department table.

Many-to-Many Relationship:

• A many-to-many relationships occurs when multiple records in a table are associated with multiple records in another table.
• Example 1: Customers and Product

Customers can purchase various products and Products can be purchased by many customers.

Example 2: Students and Courses
A student can register for many Courses and a Course may include many students

Example 3: Books and Student.
Many Books in a Library are issued to many students.

Question 3.
Differentiate DBMS and RDBMS.
Answer:

Basis of Comparison	DBMS	RDBMS
Expansion	Database Management System	Relational Database Management System
Data storage	Navigational model ie data by linked records	Relational model (in tables), ie data in tables as row and column
Data redundancy	Exhibit	Not Present
Normalization	Not performed	RDBMS uses normalization to reduce redundancy
Data access	Consumes more time	Faster, compared to DBMS.
Keys and indexes	Does not use.	used to establish a relationship. Keys are used in RDBMS.
Transaction management	Inefficient, Error-prone, and insecure	Efficient and secure.
Distributed Databases	Not supported	Supported by RDBMS.
Example	Dbase, FoxPro.	SQL Server, Oracle, MySQL, MariaDB, SQLite.

Question 4.
Explain the different operators in Relational algebra with suitable examples.
Answer:
Relational Algebra is divided into various groups:
Unary Relational Operations:

1. SELECT (symbol: σ)
2. PROJECT (symbol: π)

Relational Algebra Operations from Set Theory:

1. UNION (U)
2. INTERSECTION (∩)
3. DIFFERENCE (-)
4. CARTESIAN PRODUCT (X)

SELECT symbol: σ_c (R) with a relation R and a condition C on the attributes of R

• The SELECT operation is used for selecting a subset with tuples according to a given condition.
• Select filters out all tuples that do not satisfy C

Table A : STUDENT :

Studno	Name	Course	Year
cs1	Kannan	Big Data	II
cs2	Gowri Shankar	R Language	I
cs3	Lenin	Big Data	I
cs4	Padmaja	Python Programming	I

σ_course = <Big Data> (Student)

Studno	Name	Course	Year
csl	Kannan	Big Data	II
cs2	Lenin	Big Data	I

PROJECT (symbol: n):

• The projection eliminates all attributes of the input relation but those mentioned in the projection list.
• The projection method defines a relation that contains a vertical subset of Relation.
• Example 1 using Table A
  π_course (STUDENT)

Result:

Course :

Big Data

R language

Python Programming

Example 2 (using Table A)
π_{student, course} (STUDENT)

Studno	Course
cs1	Big Data
cs2	R language
cs3	Big Data
cs4	Python Programming

UNION (Symbol: U):

• It includes all tuples that are in tables A or in B.
• It also eliminates duplicates.
• Set A Union Set B would be expressed as A U B

Example 3
Consider the following tables

Table A
Studno	Name
cs1	Kannan
cs2	Lenin
cs3	Padmaja

Table B
Studno	Name
cs1	Kannan
cs2	Lenin
cs3	Padmaja

Result (A U B)

Table A
Studno	Name
cs1	Kannan
cs2	Gowrishankaran
cs3	Lenin
cs4	Padmaja

SET DIFFERENCE ( Symbol: -):

• The result of A – B, is a relation which includes all tuples that are in A but not in B.
• The attribute name of A has to match with the attribute name in B.
• Example 4 (using Table B):

Result:

Table
Cs4	Padmaja

INTERSECTION (symbol: ∩) A ∩ B:

• INTERSECTION Defines a relation consisting of a set of all tuple that are in both in A and B.
• However, A and B must be union-compatible.

Example 5 (using Table B)

Table A – B
cs1	Kannan
cs3	Lenin

PRODUCT OR CARTESIAN PRODUCT (Symbol: X)

• Cross product is a way of combining two relations. The resulting relation contains, both relations being combined.
• A x B means A times B, where the relation A and B have different attributes.
• This type of operation is helpful to merge columns from two relations.

Table A		‘                   Table B
studno	name	studno	subject
cs1	Kannan	cs28	Big Data
cs2	Gowri Shankar	cs62	R language
cs4	Padmaja	cs25	Python Programming

studno	name	course	subject
csl	Kannan	cs28	Big Data
csl	Kannan	cs62	R language
csl	Kannan	cs25	Python Programming
cs2	Gowri Shankar	cs28	Big Data
cs2	Gowri Shankar	cs62	R language
cs2	Gowri Shankar	cs25	Python Programming
cs4	Padmaja	cs28	Big Data
cs4	Padmaja	cs62	R language
cs4	Padmaja	cs25	Python Programming

Question 5.
Explain the characteristics of DBMS.
Answer:
Characteristics of Database Management system:

Data stored in Table	Data is never directly stored in the database. Data is stored in tables, created inside the database. DBMS also allows having relationships between tables which makes the data more meaningful and connected.
Reduced Redundancy	In the modern world, hard drives are very cheap, but earlier when hard drives were too expensive, unnecessary repetition of data in databases was a big problem But DBMS follows Normalization which divides the data in such a way that repetition is minimum.
Data Consistency	On live data, it is being continuously updated and added, maintaining the consistency of data can become a challenge. But DBMS handles it by itself.
Support Multiple user and Concurrent Access	DBMS allows multiple users to work on it( update, insert, delete data) at the same time and still manages to maintain data consistency.
Query Language	DBMS provides users with a simple query language, using which data can be easily fetched, inserted, deleted, and updated in a database.
Security	The DBMS also takes care of the security of data, protecting the data from unauthorized access. In a typical DBMS, we can create user accounts with different access permissions, using which we can easily secure our data by restricting user access.
DBMS Supports Transac­tions	It allows us to better handle and manage data integrity in real-world applications where multi-threading is extensively used.

12th Computer Science Guide Database Concepts Additional Important Questions and Answers

I. Choose the best answer (1 Mark)

Question 1.
…………………… are raw facts stored in a computer
(a) data
(b) Information
(c) row
(d) tuple
Answer:
(a) data

Question 2.
………………….is an organized collection of data, which can be stored and accessed electronically from a computer system
a) Worksheet
b) Database
c) DBMS
d) Information
Answer:
b) Database

Question 3.
……………………. is a repository collection of related data
(a) data
(b) Information
(c) database
(d) tuple
Answer:
(c) database

Question 4.
In………………….data are organized in a way that, they can be easily accessed, managed, and updated.
a) Database
b) Pointer
c) Structure
d) Object
Answer:
a) Database

Question 5.
………………….allows users to store, process, and analyze data easily.
a) My SQL
c) My SQL SQLite
b) Relational Algebra
d) DBMS
Answer:
d) DBMS

Question 6.
Find the wrong statement about DBMS?
(a) segregation of application program
(b) Maximum data Redundancy
(c) Easy retrieval of data
(d) Reduced development time
Answer:
(b) Maximum data Redundancy

Question 7.
…………………. provides protection and security to the databases
a) MySQL
b) DBMS
c) Oracle
d) Ingress
Answer:
b) DBMS

Question 8.
…………………. can be software or hardware-based, with one sole purpose of storing data.
a) MySQL
b) DBMS
c) Database
d) Ingress
Answer:
c) Database

Question 9.
Which is the language used to write commands to access, insert, update data stored in the database?
(a) DataBase Access Languages
(b) Javascript
(c) Basic
(d) Foxpro
Answer:
(a) DataBase Access Languages

Question 10.
…………………. major components are there in DBMS?
a) Four
b) Three
c) Five
d) Two
Answer:
c) Five

Question 11.
…………………. characteristics of DBMS allows to better handle and manage data integrity
a) Data redundancy
b) Data security
c) DBMS Supports Transactions
d) Data integrity
Answer:
c) DBMS Supports Transactions

Question 12.
…………………. DBMS components that manage databases to take backups, report generation.
a) Software
b) Hardware
c) Data
d) Procedures/Methods
Answer:
d) Procedures/Methods

Question 13.
…………………. in a table represents a record.
a) Row
b) Column
c) File
d) Data
Answer:
a) Row

Question 14.
Which of the following is not a DBMS component?
a) Hardware/ Software
b) Data
c) Procedures
d) Data model
Answer:
d) Data model

Question 15.
Hierarchical Model was developed by ……………………….
(a) Apple
(b) IBM
(c) Microsoft
(d) Macromedia
Answer:
(b) IBM

Question 16.
…………………. is not a type of data model?
a) Hierarchical model
b) Entity-Relationship model
c) Object model
d) Redundancy model
Answer:
d) Redundancy model

Question 17.
…………………. is an extended form of hierarchical data model.
a) ER model
b) Hierarchical mode
c) Network database model
d) Object model
Answer:
c) Network database model

Question 18.
The relational model was developed in the year ……………………..
(a) 1980
(b) 1970
(c) 1965
(d) 1985
Answer:
(b) 1970

Question 19.
The abbreviation of GIS is
a) Global Information System
b) Geographic Information System
c) Global Information Source
d) Geographic Intelligent System
Answer:
b) Geographic Information System

Question 20.
Data is represented as a simple tree-like structure form in the data model
a) Network database
b) Hierarchical model
c) ER model
d) Relational model
Answer:
b) Hierarchical model

Question 21.
ER Model Expand ………………………..
(a) Entry Relation
(b) Entity Relationship
(c) Entire Row
(d) Entity Row
Answer:
(b) Entity Relationship

Question 22.
…………………. takes care of the security of the DBMS, managing the license keys, managing user accounts and access.
a) Database Designer
b) Database Administrator
c) Database Architect
d) Data Analyst
Answer:
b) Database Administrator

Question 23.
The …………………. operation is used for selecting a subset with tuples according
to a given condition.
a) CARTESIAN PRODUCT
b) SELECT
c) Union
d) Intersection
Answer:
b) SELECT

Question 24.
Find the wrongly matched pair.
(a) Entities – Rectangle
(b) Ellipse – attributes
(c) Diamond – relationship
(d) row – square
Answer:
(d) row – square

II. Answer the following questions (2 and 3 Marks)

Question 1.
What is a database?
Answer:

• The database is a repository collection of related data organized in a way that data can be easily accessed, managed, and updated.
• The database can be software or hardware-based, with one sole purpose of storing data.

Question 2.
Write the advantages of DBMS.
Answer:

• Segrega n f application program
• Minimal date duplication or Data Redundancy
• Easy retrieval of data using the Query Language
• Reduced development time and maintenance

Question 3.
Define Data and Information.
Answer:

Data	Information
Data are raw facts stored in a computer	Information is formatted data
Data may contain any character, text, word, or number.	The information allows being utilized in a significant way

Question 4.
Define Table?
Answer:
Table is the entire collection of related data in one table, referred to as a File or Table where the data is organized as row and column.

Question 5.
Define: Database structure
Answer:

• Table is the entire collection of related data in one table, referred to as a File or Table where the data is organized as row and column.
• Each row in a table represents a record, which is a set of data for each database entry.
• Each table column represents a Field, which groups each piece or item of data among the records into specific categories or types of data.

Example: StuNo., StuName, StuAge, StuClass, StuSec.,

• A Table is known as a RELATION S
• A Row is known as a TUPLE S
• A column is known as an ATTRIBUTE

Question 6.
Write a note on relational Algebra?
Answer:
Relational Algebra is a procedural query language used to query the database tables using SQL. Relational algebra operations are performed recursively on a relation (table) to yield output.

Question 7.
What is Data model?
Answer:

• A data model describes how the data can be represented and accessed from the software after complete implementation.
• It is a simple abstraction of a complex real-world data gathering environment.
• The main purpose of the data model is to give an idea of how the final system or software will look after development is completed.

Question 8.
What is Relational Algebra?
Answer:

• Relational Algebra, was first created by Edgar F Codd while at IBM.
• It was used for modeling the data stored in relational databases and defining queries on it.
• Relational Algebra is a procedural query language used to query the database tables using SQL.
• Relational algebra operations are performed recursively on a relation (table) to yield an output.
• The output of these operations is a new relation, which might be formed by one or more input relations.

Question 9.
List the types of data model.
Answer:

• Hierarchical Model
• Relational Model
• Network Database Model
• Entity-Relationship Model
• Object Model

Question 10.
List the types of DBMS users.
Answer:

• Database Administrators (DBA)
• Application or software developers
• End-User
• Database designers

Question 11.
Write short notes on Relational Data Model.
Answer:

• The Relational Database model was first proposed by E.F. Codd in 1970 . Nowadays, it is the most widespread data model used for database applications around the world.
• The basic structure of data in the relational model is tables (relations). All the information related to a particular type is stored in rows of that table. Hence tables are also known as relations in a relational model. A relation key is an attribute which uniquely identifies a particular tuple.

III. Answer the following questions (5 Marks)

Question 1.
Explain the components of DBMS
Answer:
The Database Management System can be divided into five major components namely 1. Hardware, 2. Software, 3. Data, 4. Procedures/Methods
5. Database Access Languages

1. Hardware:
The computer, hard disk, I/O channels for data, and any other physical component involved in the storage of data

2. Software:
This main component is a program that controls everything.
The DBMS software is capable of understanding the Database Access Languages and interprets them into database commands for execution.

3. Data:
It is that resource for which DBMS is designed. DBMS creation is to store and utilize data.

4. Procedures/ Methods:
They are general instructions to use a database management system such as the installation of DBMS, manage databases to take backups, report generation, etc

5. DataBase Access Languages :

• They are the languages used to write commands to access, insert, update and delete data stored in any database.
• Examples of popular DBMS: Dbase, FoxPro

Tamilnadu State Board New Syllabus Samacheer Kalvi 12th Computer Applications Guide Pdf Chapter 6 PHP Conditional Statements Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 12th Computer Applications Solutions Chapter 6 PHP Conditional Statements

12th Computer Applications Guide PHP Conditional Statements Text Book Questions and Answers

Part I

Choose The Correct Answers

Question 1.
What will be the output of the following PHP code?
<?php
$x;
if ($x)
print “hi”;
else
print “how are u”;
?>
a) how are u
b) hi
c) error
d) no output
Answer:
c) error

Question 2.
What will be the output of the following PHP code ?
<?php
$x = 0;
if ($x++)
print “hi”;
else
print “how are u”;
?>
a) hi
b) no output
c) error
d) how are u
Answer:
a) hi

Question 3.
What will be the output of the following PHP code ?
<?php
$x;
if ($x == 0)
print “hi”;
else
print “how are u”;
print “hello”
?>
a) how are uhello
b) hihello
c) hi
d) no output
Answer:
a) how are uhello

Question 4.
Statement which is used to make choice between two options and only option is to be performed is written as
a) if statement
b) if else statement
c) then else statement
d) else one statement
Answer:
b) if else statement

Question 5.
What will be the output of the following PHP code ?
<?php
$a =
if ($a)
print “all”;
if
else
print “some”;
?>
a) all
b) some
c) error
d) no output
Answer:
c) error

Question 6.
What will be the output of the following PHP code ?
<?php
$a = “”;
if ($a)
print “all”;
if
else
print “some”;
?>
a) all
b) some
c) error
d) no output

Question 7.
What will be the output of the following PHP code ?
<?php
$x = 10;
$y = 20;
if ($x > $y + $y != 3)
print “hi”;
else
print “how are u”;
?>
a) how are u
b) hi
c) error
d) no output
Answer:
b) hi

Question 8.
What will be the output of the following PHP code ?
<?php
$x = 10;
$y = 20;
if ($x > $y && 1||1)
print “hi”;
else
print “how are u”;
?>
a) how are u
b) hi
c) error
d) no output
Answer:
b) hi

Question 9.
What will be the output of the following PHP code ?
<?php
if (-100)
print “hi”;
else
print “how are u”;
?>
a) how are u
b) hi
c) error
d) no output
Answer:
a) how are u

Part II

Short Answers

Question 1.
Define Conditional Statements in PHP
Answer:
Conditional statements are useful for writing decision-making logics. It is the most important feature of many programming languages, including PHP. They are implemented by the following types:

1. if Statement
2. if…else Statement
3. if…else if….else Statement
4. switch Statement

Question 2.
Define if statement in PHP.
Answer:
If a statement executes a statement or a group of statements if a specific condition is satisfied as per the user expectation.
Syntax:
if (condition)
{
Execute statement(s) if condition is true;
}

Question 3.
What is an if-else statement in PHP?
Answer:
If else statement in PHP:

1. If a statement executes a statement or a group of statements if a specific condition is satisfied by the user expectation.
2. When the condition gets false (fail) the else block is executed.

Syntax:
if (condition)
{
Execute statement(s) if condition is true;
}
else
{
Execute statement(s) if condition is false;
}

Question 4.
List out Conditional Statements in PHP.
Answer:

• if Statement
• if…else Statement
• if…else if….else Statement
• switch Statement

Question 5.
Write Syntax of the If else statement in PHP.
Answer:
if (condition)
{
Execute statement(s) if condition is true;
}
else
{
Execute statement(s) if condition is false;
}

Question 6.
Define if…elseif….else Statement in PHP.
Answer:

• If-elseif-else statement is a combination of if-else statement.
• More than one statement can execute the condition based on user needs.

Question 7.
Usage of Switch Statement in PHP.
Answer:

• The switch statement is used to perform different actions based on different conditions.
• Switch statements work the same as if statements but they can check for multiple values at a time.

Question 8.
Write Syntax of the Switch statement.
Answer:
switch (n)
{
case label1:
code to be executed if n=la bel1;
break;
case Iabel2:
code to be executed if n=label2;
break;
case label3:
code to be executed if n=iabel3;
break;
…
default:
code to be executed if n is different from all labels;
}

Question 9.
Compare if and if-else statement.
Answer:

If Statement	If else Statement
if statement checks a condition and exe­cutes a set of state­ments when this con­dition is true, it does not do anything when the condition is false.	if-else statement checks a condition and executes a set of statements when this condition is true, it executes another set of statements when the condition is false.

Part III

Explain in brief answer

Question 1.
Write the features Conditional Statements in PHP.
Answer:
PHP Conditional statements:

1. Conditional statements are useful for writing decision-making logics.
2. It is most important feature of many programming languages, including PHP.
3. They are implemented by the following types:
4. if Statement
5. if…else Statement
6. if…elseif….else Statement
7. switch Statement

Question 2.
Write is the purpose of if elseif else stament.
Answer:

• A user can decide among multiple options.
• The if statements are executed from the top I down.
• As soon as one of the conditions controlling the if is true, the statement associated with that if is executed, and the rest of the ladder is bypassed.
• If none of the conditions is true, then the final else statement will be executed.
• More than one statement can execute the condition based on user needs.

Question 3.
Differentiate Switch and if-else statement.
Answer:

Switch statement	if-else statement
Switch statement uses single expression for multiple choices.	the if-else statement uses multiple statements for multiple choices.
Switch statement test only for equality.	if-else statement test for equality as well as for logical expression.
Switch statement execute one case af­ter another till a break statement is appeared or the end of switch statement is reached.	Either if statement will be executed or else statement is executed.

Question 4.
Write Short notes on the Switch statement.
Answer:

1. The switch statement is used to perform different actions based on different conditions.
2. It tests for equality only.
3. It uses default value when all the case values are not matched.
4. It can have multiple ease values.

Question 5.
Differentiate if statement and if-else statement.
Answer:

If statement	if else if else stamen
If-else if-else statement is a combination of if-else statement.	It consists of a single “if statement”. There is no “else” statement here.
More than one state­ment can execute the condition based on user needs	Only one statement can execute
If the condition is false, there are more alterna­tives are there	If the condition is false, there is no alternatives

Part IV

Explain in detail

Question 1.
Explain Functions of Conditional Statements in PHP.
Answer:
Function Conditional Statements:

1. Function conditional statement is the function specified inside the conditional statements.
2. We can’t call a conditional function before its definition.

Syntax:
if(expression)
{
function function_name( )
{
block of statements;
}
}
function_name( ); // calling function.
Eg:
<? php
display( );
if(TRUE)
{
function display( )
{
echo “condition and function”;
}
}
Output: condition and function

Question 2.
Discuss in detail about Switch statement with an example.
Answer:

• The switch statement is used to perform different actions based on different conditions.
• Switch statement test only for equality.
• Switch statement execute one case after another till a break statement has appeared or the end of the switch statement is reached.

Syntax;
switch (n)
{
case label 1:
code to be executed if n=label1;
break;
case label 2:
code to be executed If n=label2;
break;
case label3:
code to be executed if n=label3;
break;
…
default:
code to be executed if n is different from all labels;
}

Example;
<?php
$favcolor = “red”;
switch ($favco!or) {
case “red”:
echo “Your favorite color is red!”;
break;
case “blue”:
echo “Your favorite color is blue!”;
break;
case “green”:
echo “Your favorite color is green!”;
break;
default:
echo “Your favorite color is neither red, blue, nor green!”;
}
?>

Question 3.
Explain the process of Conditional Statements in PHP?
Answer:
Conditional statements are useful for writing decision-making logics. It is the most important feature of many programming languages, including PHP. They are implemented by the following types:

(i) if Statement:
If statement executes a statement or a group of statements if a specific condition is satisfied as per the user expectation.

(ii) if…else Statement:
If statement executes a statement or a group of statements if a specific condition is satisfied by the user expectation. When the condition gets false (fail) the else block is executed.

(iii) if…elseif….else Statement:
If-elseif-else statement is a combination of if-else statement. More than one statement can execute the condition based on user needs.

(iv) Switch Case:
The switch statement is used to perform different actions based on different conditions.

Question 4.
Explain concepts of if elseif else statement.
Answer:

• If-elseif-else statement is a combination of if-else statement.
• More than one statement can execute the condition based on user needs.

Syntax:
if (1st condition)
{
Execute statement(s) if condition is true;
}
elseif(2nd condition)
{
Execute statement(s) if 2ndcondition is true;
}
else
{
Execute statement(s) if both conditions are false;
}

Example Program:
<?php
$Pass_Mark=35;
$first_class=60;
$Student_Mark=70;
if ($Student_Mark>= $first_class){ echo “The Student is eligible for the promotion with First Class”;
}
elseif ($Student_Mark>= $Pass_Mark){ echo “The Student is eligible for the promotion”;
}
else {
echo “The Student is not eligible for the promotion”;
}?>

Question 5.
Explain the if-else statement in PHP.
Answer:
If else statement in PHP:
If a statement executes a statement or a group of statements if a specific condition is satisfied by the user expectation. When the condition gets false (fail) the else block is executed.
Syntax:
if (condition)
{
Execute statement(s) if condition is true;
} else
{
Execute statement(s) if condition is false;
}
Example:
<?php
$Pass_Mark=35;
$Student_Mark=70;
if ($Student_Mark>= $Pass_Mark)
{
echo “The Student is eligible for the promotion”;
}
else
{
echo “The Student is not eligible for the promotion”; }
?>

12th Computer Applications Guide PHP Conditional Statements Additional Important Questions and Answers

Part A

Choose The Correct Answers:

Question 1.
How many types of PHP conditional statements are there?
(a) 2
(b) 3
(c) 4
(d) 5
Answer:
(c) 4

Question 2.
What will be the output of the following PHP code ?
<?php
if(0.0)
print”hi”;
else
print”how are u”;
?>
a) how are u
b) hi
c) error
d) no output
Answer:
a) how are u

Question 3.
The ……………………….. statement is used to perform different actions based on different conditions.
Answer:
switch

Question 4.
What will be the output of the following PHP code ?
<?php
$a=”l”;
switch($a)
{
case1:
break;
print”hi”;
case2:
print’tiello”;
break;
default:
print”hil”;
>
?>
a) hihellohi1
b) hi
c) hihi1
d) hi1
Answer:
a) hihellohi1

Question 5.
What will be the output of the following PHP code ?
<?php
$x=l;
if($x=$x&0)
print$x;
else
break;
?>
a) 0
b) 1
c) error
d) no output
Answer:
c) error

Question 6.
Which of the following can check for multiple values at a time?
(a) If
(b) If else
(c) Nested else
(d) Switch
Answer:
(d) Switch

Very Short Answers

Question 1.
How conditional statements perform?
Answer:
It performs different actions for different decisions in programing language

Question 2.
What is an “if statement” in PHP?
Answer:
The If Statement is a way to make decisions based upon the result of a condition.

Question 3.
How switch statement and if statement differs?
Answer:
Switch statements work the same as if statements but they can check for multiple values at a time

Match the following:

1. Simple if statements – Multiple branching
2. If-else statement – Combination of if-else statement
3. If elseif else statement – Only one option
4. Switch case statement – Alternative statement

Part B

Short Answers

Question 1.
Write the syntax of the If statement.
Answer:
if (condition)
{
Execute statement(s) if condition is true;
}

Question 2.
What is mean by If else ladder?
Answer:

• Else executes the following block of statements if the condition in the corresponding if is false.
• After the else, if another condition is to be checked, then an if statement follows the else. This is else if and is called as if-else ladder.

SYNTAX:

1. If statement
Answer:
if (condition)
{
Execute statement(s) if condition is true;
}

2. If else statement
if (condition)
{
Execute statement(s) if condition is true;
}
else
{
Execute statement(s) if condition is false;
}

3. If elseif else statement
if (1st condition)
{
Execute statement(s) if condition is true;
}
elseif(2nd condition)
{
Execute statement(s) if 2ndcondition is true;
}
else
{
Execute statement(s) if both conditions are false;
}

4. Switch Case:
switch (n) { case label 1:
code to be executed if n=label1;
break;
case Iabel2:
code to be executed if n=label2;
break;
case Iabel3:
code to be executed if n=label3;
break;
…
default:
code to be executed if n is different from all labels;
}

Part C

Explain in brief answer

Question 1.
Give the Syntax for If else statements in PHP?
Answer:
if (1st condition)
{
Execute statement(s) if condition is true;
}
elseif(2nd condition)
{
Execute statement(s) if 2nd condition is true;
}
else
{
Execute statement(s) if both conditions are false;
}

Programs

Question 1.
Write a php program to birthday greetings using if statement.
Answer:
<?php
$date=date(“m-d”);
if ($date==»01T0»)
{
echo “Wishing you a very Happy Birthday”;
}
?>

Question 2.
Write a php program to check whether the given number is positive or negative.
Answer:
<?php
$x = -12;
if ($x > 0)
{
echo “The number is positive”;
}
else{
echo “The number is negative”;
}
?>

Question 3.
Write a PHP program to display independence day and republic day the greetings using If elseif else statement
Answer:
<?php
$x = “August”;
if ($x == “January”) {
echo “Happy Republic Day”;
}
elseif ($x == “August”) {
echo “Happy Independence Day!!!”;
}
else{
echo “Nothing to show”;
}
?>

Part D

Explain in detail

Question 1.
Write a PHP code to display the days of weak using switch statement
Answer:
<?php
$today=date(“D”);
switch($today)
{
case”Mon”:
echo’Today is Monday.
break;
case”Tue”:
echo’Today is Tuesday.”;
break;
case”Wed”:
echo’Today is Wednesday.”;
break;
case’Thu”:echo’Today is Thursday.”;
break;
case”Fri”:
echo’Today is Friday. Party tonight.”;
break;
case”Sat”:echo’Today is Saturday.”;
break;
case”Sun”:
echo’Today is Sunday.”;
break;
default:
echo”No information available for that day.”;
break;
}
?>

Question 2.
Write a PHP program to display week days using switch case statement.
Answer:
<?php
$n = “February”;
switch($n) {
case “January”:
echo “Its January”;
break;
case “February”:
echo “Its February”;
break;
case “March”:
echo “Its March”;
break;
case “April”:
echo “Its April”;
break;
case “May”:
echo “Its May”;
break;
case “June”:
echo “Its June”;
break;
case “July”:
echo “Its July”;
break;
case “August”:
echo “Its August”;
break;
case “September”:
echo “Its September”;
break;
case “October”:
echo “Its October”;
break;
case “November”:
echo “Its November”;
break;
case “December”:
echo “Its December”;
break;
default:
echo “Doesn’t exist”;
}
?>

Tamilnadu State Board New Syllabus Samacheer Kalvi 7th Tamil Guide Pdf Chapter 7.2 வயலும் வாழ்வும் Questions and Answers, Summary, Notes.

Tamilnadu Samacheer Kalvi 7th Tamil Solutions Chapter 7.2 வயலும் வாழ்வும்

கற்பவை கற்றபின்

Question 1.
வேளாண்மை சார்ந்த கருவிகளின் பெயர்களை எழுதி வருக.
Answer:
ஏர், மண்வெட்டி, உழவு இயந்திரம், விதைக்கலப்பை, களைவெட்டும் இயந்திரம், நீர் பாசன இயந்திரம், ஊசலாடும் கூடை, வேளாண் வானூர்தி, தாள்க்கத்தி, கதிரடி இயந்திரம், களம், படல், உமி நீக்கி, இணை அறுவடை இயந்திரம்.

பாடநூல் மதிப்பீட்டு வினா

சரியான விடையைத் தேர்ந்தெடுத்து எழுதுக.

Question 1.
உழவர் சேற்று வயலில் ……………… நடுவர்.
அ) செடி
ஆ) பயிர்
இ) மரம்
ஈ) நாற்று
Answer:
ஈ) நாற்று

Question 2.
வயலில் விளைந்து முற்றிய நெற்பயிர்களை ………………… செய்வர்.
அ) அறுவடை
ஆ) உழவு
இ) நடவு
ஈ) விற்பனை
Answer:
அ) அறுவடை

Question 3.
‘தேர்ந்தெடுத்து’ என்னும் சொல்லைப் பிரித்து எழுதக் கிடைப்பது ………………
அ) தேர் + எடுத்து
ஆ) தேர்ந்து + தெடுத்து
இ) தேர்ந்தது + அடுத்து
ஈ) தேர்ந்து + எடுத்து
Answer:
ஈ) தேர்ந்து + எடுத்து

Question 4.
‘ஓடை + எல்லாம்’ என்பதனைச் சேர்த்தெழுதக் கிடைக்கும் சொல ……………….
அ) ஓடை எல்லாம்
ஆ) ஓடையெல்லாம்
இ) ஓட்டையெல்லாம்
ஈ) ஓடெல்லாம்
Answer:
ஆ) ஓடையெல்லாம்

பொருத்துக.

1. நாற்று – பறித்தல்
2. நீர் – அறுத்தல்
3. கதிர் – நடுதல்
4. களை – பாய்ச்சுதல்
Answer:
1. நாற்று – நடுதல்
2. நீர் – பாய்ச்சுதல்
3. கதிர் – அறுத்தல்
4. களை – பறித்தல்

வயலும் வாழ்வும் பாடலில் உள்ள மோனை,எதுகைச் சொற்களை எழுதுக.

பேச்சு வழக்குச் சொற்களை எழுத்து வழக்கில் எழுதுக.

(எ.கா.) போயி – போய்
பிடிக்கிறாங்க – பிடிக்கிறார்கள்
வளருது – வளர்கிறது
இறங்குறாங்க – இறங்குகிறார்கள்
வாரான் – வரமாட்டான்

குறுவினா

Question 1.
உழவர்கள் எப்போது நண்டு பிடித்தனர்?
Answer:
நாற்றுப் பறிக்கும்போது உழவர்கள் வயல் வரப்பில் உள்ள நண்டுகளைப் பிடித்தனர்.

Question 2.
நெற்கதிரிலிருந்து நெல்மணியை எவ்வாறு பிரிப்பர்?
Answer:
கிழக்கத்தி மாடுகளைக் கொண்டு மிதிக்கச் செய்து நெற்கதிரிலிருந்து நெல்மணியைப் பிரிப்பர். இதற்கு போரடித்தல் என்று பெயர்.

சிறுவினா

Question 1.
உழவுத்தொழிலின் நிகழ்வுகளை வரிசைப்படுத்தி எழுதுக.
Answer:
ஒரு சாணுக்கு ஒரு நாற்று வீதம் சுறுசுறுப்பாக நட்டனர். நடவு நட்ட வயலின் மண்குளிருமாறு மடைவழியே நீர்பாய்ச்சினர். நட்ட நெற்பயிர்கள் வரிசையாக வளர்ந்து செழித்தன. பால் பிடித்து முற்றிய நெல்மணிகள் மனம் மயங்குமாறு விளைந்தன. அறுவடை செய்யும் ஆட்களுக்குப் பணம் கொடுத்தனர்.

அறுவடை செய்த நெல்தாள்களைக் கட்டுகளாகக் கட்டித் தலைக்குச் சும்மாடு வைத்துத் தூக்கிச் சென்று களத்தில் சேர்த்தனர். கதிரடித்த நெல்தாள்களைக் கிழக்கத்தி மாடுகளைக் கொண்டு மிதிக்கச் செய்தனர். மாடுகள் மிதித்த நெற்கதிர்களில் இருந்து நெல்மணிகள் மணிமணியாய் உதிர்ந்தன.

சிந்தனை வினா

Question 1.
உழவுத்தொழிலில் காலந்தோறும் ஏற்பட்டுவரும் மாற்றங்கள் பற்றி எழுதுக.
Answer:
ஆற்றங்கரையில் நாகரிகம் உருவாகக் காரணமானது உழவுத்தொழில். விதைகளை விதைப்பதும், அவற்றுக்கு நீர்பாய்ச்சி வளர்ப்பது மட்டுமே பழங்காலத்தில் நடைபெற்றது. பின்னர், மனிதன் தன் சுய அறிவால் உழவுத்தொழிலுக்கு உதவியாக மாடுகளைப் பயன்படுத்தி இயற்கை எருக்களைக் கொண்டு பயிரிட்டான். பின்னர் அறிவியல் வளர்ச்சியின் காரணமாக, உழுகருவிகளையும் விதைத்தல் கருவிகளையும், பூச்சிக்கொல்லி, செயற்கை உரங்கள் ஆகியவற்றைப் பயன்படுத்தி விளைச்சலைப் பெருக்கினான்.

கூடுதல் வினா

கோடிட்ட இடங்களை நிரப்புக.

1. நாட்டுப்புறங்களில் உழைக்கும் மக்கள் தங்கள் களைப்புத் தெரியாமல் இருப்பதற்காகப் பாடும் பாடலே ……………. எனப்படுகிறது.
2. நாட்டுப்புறப்பாடல்களை ………………. என்றும் வழங்குவர்.
3. பல்வேறு தொழில்கள் குறித்த நாட்டுப்புறப்பாடல்களை ………………….. என்னும் நூலில் கி.வா. ஜெகந்நாதன் தொகுத்துள்ளார்.
Answer:
1. நாட்டுப்புறப்பாடல்
2. வாய்மொழி இலக்கியம்
3. மலை அருவி

சிறுவினா

Question 1.
போரடித்தல் என்றால் என்ன?
Answer:
அறுவடை செய்த நெற்கதிர்களைக் களத்தில் அடித்து நெல்லைப் பிரிப்வர். நெல் தாளில் எஞ்சியிருக்கும் நெல்மணிகளைப் பிரிப்பதற்காக மாடுகளைக் கொண்டு மிதிக்கச் செய்வர். இதற்குப் போரடித்தல் என்று பெயர்.

சொல்லும் பொருளும்

1. குழி – நில அளவைப்பெயர்
2. சீலை – புடலை
3. சாண் – நீட்டல் அளவைப்பெயர்
4. மடை – வயலுக்கு நீர் வரும் வழி
5. மணி – முற்றிய நெல்
6. கழலுதல் – உதிர்தல்
7. சும்மாடு – பாரம் சுமப்பவர்கள் தலையில் வைத்துக் கொள்ளும் துணிச்சுருள

Tamilnadu State Board New Syllabus Samacheer Kalvi 4th Maths Guide Pdf Term 3 Chapter 2 Numbers Ex 2.6 Textbook Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 4th Maths Solutions Term 3 Chapter 2 Numbers Ex 2.6

Add and subtract the following problems using multiples of 10, 100 (Mentally)

Question 1.
745 + 40 = _______
Hint:

4 + 4 = 8
745 + 40 = 785
Answer:
785

Question 2.
328 + 30 = _______
Hint:

2 + 3 = 5
328 + 30 = 358
Answer:
358

Question 3.
566 + 20 = _______
Hint:

6 + 2 = 8
566 + 20 = 586
Answer:
586

Question 4.
475 + 100 = _______
Hint:

4 + 1 = 5
475 + 100 = 575
Answer:
575

Question 5.
686 + 300 = _______
Hint:

6 + 3 = 9
686 + 300 = 986
Answer:
986

Question 6.
345 + 600 = _______
Hint:

3 + 6 = 9
345 + 600 = 945
Answer:
945

Question 7.
6348 – 10 = _______
Hint:

4 – 1 = 3
6348 – 10 = 6338
Answer:
6338

Question 8.
541 – 40 = _______
Hint:

4 – 4 = 0
541 – 40 = 501
Answer:
501

Question 9.
495 – 300 = _______
Hint:

4 – 3 = 1
495 – 300 = 195
Answer:
195

Question 10.
657 – 500 = _______
Hint:

6 – 5 = 1
657 – 500 = 157
Answer:
157

Question 11.
895 – 500 = _______
Hint:

8 – 5 = 3
895 – 500 = 395
Answer:
395

Question 12.
365 – 300 = _______
Hint:

3 – 3 = 0
365 – 300 = 65
Answer:
65