## MCQ Questions for Class 11 Physics Chapter 2 Units and Measurements with Answers

## 1. The base quantity among the following is

(1) Speed

(2) Weight

(3) Length

(4) Area

**Answer (3)**

There are seven base quantities,

(i) Mass

(ii) Length

(iii) Time

(iv) Current

(v) Amount of substance

(vi) Luminous intensity

(vii) Temperature

### 2. Which of the following is not a unit of time?

(1) Second

(3) Hour

(4) Light year

**Answer (4)**

**Light year is the unit of distance**

**1 light year = 9.46 × 1015 m**

### 3. One astronomical unit is a distance equal to

(1) 9.46 × 1015 m

**(2) 1.496 × 1011 m**

(3) 3 × 108 m

(4) 3.08 × 10¹6 m

Answer (2)

### 4. Ampere second is a unit of

(1) Current

**(2) Charge**

(3) Energy

(4) Power

Answer (2)

### 5. The most precise reading of the mass of an object, among the following is

(1) 20 g

(2) 20.0 g

**(3) 20.01 g**

(4) 20 × 100 g

Answer (3)

### 6. The most accurate reading of the length of a 6.28 cm long fibre is

(1) 6 cm

**(2) 6.5 cm**

(3) 5.99 cm

(4) 6.0 cm

Answer (2)

### 7. Which of the following is a unit that of force?

(1) N m

**(2) mN**

(3) nm

(4) N s

Answer (2)

### 8. The number of significant figures in a pure number 410 is

(1) Two

(2) Three

(3) One

(4) Infinite

Answer (4)

Related: MCQ on Chemical Bonding with Answers Pdf

### 9. Thickness of a pencil measured by using a screw gauge (least count .001 cm) comes out to be 0.802 cm. The percentage error in the measurement is

**(1) 0.125%**

(2) 2.43%

(3) 4.12%

(4) 2.14%

Answer (1)

### 10. The relative error in the measurement of the side of a cube is 0.027. The relative error in the measurement of

its volume is

(1) 0.027

(2) 0.054

**(3) 0.081**

(4) 0.046

Answer (3)

### MCQ Questions for Class 11 Physics Chapter 2 Units and Measurements with Answers

### 11. Zero error in an instrument introduces

**(1) Systematic error**

(2) Random error

(3) Least count error

(4) Personal error

Answer (1)

### 12. A packet contains silver powder of mass 20.23 g ± 0.01 g. Some of the powder of mass 5.75 g ± 0.01 g is

taken out from it. The mass of the powder left back is

(1) 14.48 g ± 0.00 g

**(2) 14.48 ± 0.02 g**

(3) 14.5 g ± 0.1 g

(4) 14.5 g ± 0.2 g

**Answer (2)**

m1 = 20.23 g ± 0.01 g

m2 = (5.75 ± 0.01) g

m1 – m2 = [(20.23 – 5.75) ± 0.02] g

m (14.48 0.02) g

### 13. The addition of three masses 1.6 g, 7.32 g and 4.238 g, addressed upto proper decimal places is

(1) 13.158 g

**(2) 13.2 g**

(3) 13.16 g

(4) 13.15 g

Answer (2)

### 14. We can reduce random errors by

**(1) Taking large number of observations**

(2) Corrected zero error

(3) By following proper technique of experiment

(4) Both (1) & (3)

Answer (1)

### 15. The number of significant figures in the measured value 0.0204 is

(1) Five

**(2) Three**

(3) Four

(4) Two

Answer (2)

### 16. The number of significant figures in the measured value 26000 is

(1) Five

**(2) Two**

(3) Three

(4) Infinite

Answer (2)

The trailing zeros are not significant.

So, only two digits are significant.

### 17. The number of significant zeroes present in the measured value 0.020040, is

(1) Five

(2) Two

(3) One

**(4) Three**

Answer (4)

Zeores appearing between and after non-zero numbers are significant.

0.020040

### 18. The number of significant figures in the measured value 4.700 m is the same as that in the value

(1) 4700 m

(2) 0.047 m

(3) 4070 m

**(4) 470.0 m**

Answer (4)

4.700 Four significant figures.

Also, 470.0 m four significant figures.

### 19. If a calculated value 2.7465 g contains only three significant figures, the two insignificant digits in it are

(1) 2 and 7

(2) 7 and 4

**(3) 6 and 5**

(4) 4 and 6

Answer (3)

2.7465 g Last two digits are most insignificant.

### 20. Round off the value 2.845 to three significant figures.

(1) 2.85

(2) 2.84

(3) 2.80

(4) 2.83

Answer (2)

### MCQ Questions for Class 11 Physics Chapter 2 Units and Measurements with Answers

### 21. A length 5.997 m rounded off to three significant figures is written as

(1) 6.00 m

(2) 5.99 m

(3) 5.95 m

(4) 5.90 m

Answer (1)

### 22. The order of the magnitude of speed of light in SI unit is

(1) 16

(2) 8

(3) 4

(4) 7

Answer (2)

### 23. The values of a number of quantities are used in a mathematical formula. The quantity that should be most precise and accurate in measurement is the one

(1) Having smallest magnitude

(2) Having largest magnitude

(3) Used in the numerator

(4) Used in the denominator

Answer (1)

### 24. The dimensional formula for energy is

(1) [MLT–2]

(2) [ML2T–2]

(3) [M–1L2T]

(4) [M L2 T]

Answer (2)

### 25. The pair of the quantities having same dimensions is

(1) Displacement, velocity

(2) Time, frequency

(3) Wavelength, focal length

(4) Force, acceleration

Answer (3

### 26. The uncertain digit in the measurement of a length reported as 41.68 cm is

(1) 4

(2) 1

(3) 6

(4) 8

Answer (4)

41.68 cm

### 27. We can reduce random errors by

(1) Taking large number of observations

(2) Corrected zero error

(3) By following proper technique of experiment

(4) Both (1) & (3)

Answer (1)

### 28. The number of significant figures in the measured value 0.0204 is

(1) Five

(2) Three

(3) Four

(4) Two

Answer (2)

The non-zero digits after the decimal places are significant.

### 29. The number of significant figures in the measured value 26000 is

(1) Five

(2) Two

(3) Three

(4) Infinite

Answer (2)

The trailing zeros are not significant.

So, only two digits are significant.

### 30. The number of significant zeroes present in the measured value 0.020040, is

(1) Five

(2) Two

(3) One

(4) Three

Answer (4)

Zeores appearing between and after non-zero numbers are significant.

0.020040

### Units and Measurements Class 11 MCQs Questions with Answers

### 31. The number of significant figures in the measured value 4.700 m is the same as that in the value

(1) 4700 m

(2) 0.047 m

(3) 4070 m

Related: Electric current class 10 MCQ Pdf

(4) 470.0 m

Answer (4)

4.700 Four significant figures.

Also, 470.0 m four significant figures.

### 32. If a calculated value 2.7465 g contains only three significant figures, the two insignificant digits in it are

(1) 2 and 7

(2) 7 and 4

(3) 6 and 5

(4) 4 and 6

Answer (3)

### 33. The exchange particles responsible for weak interactions are

(1) Gluons

(2) A-mesons

(3) Photons

(4) W and Z bosons

Answer (4)

Weak interaction takes place through the exchange of BOSONS W and Z bosons

### 34. Maxwell unified

(1) Electricity with gravitation

(2) Electricity with magnetism

(3) Electromagnetism with optics

(4) Electromagnetism with weak interaction

Answer (3)

Maxwell unified electromagnetism with optics.

### 35. Which of the following is not a derived force?

(1) Tension in a string

(2) van der Waal forces

(3) Nuclear force between proton-proton

(4) Electrostatic force between proton-proton

Answer (4)

Electrostatic force between proton-proton is a fundamental force.

### 36. Which one of the following does not experience strong nuclear force?

(1) Leptons

(2) Baryons

(3) Hadrons

(4) Proton

Answer (1)

Leptons doesn't experience strong nuclear force.

### 37. Which pair do not have equal dimensions?

(1) Energy and torque (2) Force and impulse

(3) Angular momentum and Planck’s constant (4) Elastic modulus and pressure

Answer (2)

Force [MLT–2]

Impulse [MLT–1]

### 38. The dimensions of Planck’s constant equals to that of

(1) Energy (2) Momentum (3) Angular momentum (4) Power

Answer (3)

### 39. The unit of length, velocity and force are doubled. Which of the following is the correct change in the other

units?

(1) Unit of time is doubled

(2) Unit of mass is doubled

(3) Unit of momentum is doubled

(4) Unit of energy is doubled

Answer (3)

### 40. Even if a physical quantity depends upon three quantities, out of which two are dimensionally same, then the

formula cannot be derived by the method of dimensions. This statement

(1) May be true

(2) May be false

(3) Must be true

(4) Must be false

Answer (3)

This statement is completely correct. If a quantity depends upon two other quantities which are dimensionally

same then formula's validity can be checked but it can't be derived by the method of dimensions.

### Units and Measurements Class 11 MCQs Questions with Answers

### 41. A : Absolute error in a physical quantity can be positive, negative or zero.

R : Absolute error is the difference in measured value and true value of physical quantity.

Answer (4) Absolute error is always positive as it is true value measured value

### 42. A : A unitless physical quantity must be dimensionless.

R : A pure number is always dimensionless.

Answer (2) : If a quantity doesnot have units so definitely it will be dimensionless but reverse is not true.

Pure number also dimensionless.

### 43. A : Absolute error is unitless and dimensionless.

R : All type of errors are unitless and dimensionless.

Answer (4)

Absolute error is not dimensionless rather it will having dimensions of the measured quantity.

### 44. A : Higher is the accuracy of measurement, if instrument have smaller least count.

R : Smaller the percentage error, higher is the accuracy of measurement.

Answer (2)

Higher accuracy means higher precisions.

So, error will be very smaller.

Low least count means low error and hence high accuracy.

### 45. A : In a measurement, two readings obtained are 20.004 and 20.0004. The second measurement is more

precise.

Related: Work and energy Class 9 MCQs questions with answers

R : Measurement having more decimal places is more precise.

Answer (1)

### 46. A : All physically correct equations are dimensionally correct.

R : All dimensionally correct equations are physically correct.

Answer (3)

If an equation is physically correct it has to be dimensionally correct also.

But the reverse is not true.

### 47. A : Physical relations involving addition and subtraction cannot be derived by dimensional analysis.

R : Numerical constants cannot be deduced by the method of dimensions.

Answer (2)

Those equations carrying multiplication and divisions of physical quantities can be derived but not valid for

addition or subtraction.

### 48. A : If displacement y of a particle executing simple harmonic motion depends upon amplitude a angular

frequency and time t then the relation y = a sin t cannot be dimensionally achieved.

R : An equation cannot be achieved by dimensional analysis; if it contains dimensionless expressions.

Answer (1)

Assertion and reason is correct and correctly explains assertion.

### 49. A : An exact number has infinite number of significant digits.

R : A number, which is not a measured value has infinite number of significant digits.

Answer (2)

### 50: Light year is a unit of

(a) time

(b) distance

(c) sunlight intensity

(d) mass

Answer. b) distance

### Units and Measurements Class 11 MCQs Questions with Answers

### 51: The dimensional formula for Planck’s constant is

(a) [MLT]

(b) [ML2T-1]

(c) [M2L2T-1]

(d) [ML1T-1]

Answer. b) [ML2T-1] (Hint use E = hν)

### 52: The surface tension of a liquid is 70 dyne/cm. In MKS system its value is?

(a) 70 N/m

(b) 7 ✕ 10-2 N/m

(c) 7 ✕ 102 N/m

(d) 7 ✕ 103 N/m

Answer. b) 7 ✕ 10-2 N/m

### 53: The dimensions of Kinetic energy is same as that of

(a) Force

(b) Pressure

(c) Work

(d) Momentum

Answer. c) Work

### 54: At 4° C, the density of water is equal to

(a) 10-3 kg m-3

(b) 10-2 kg m-3

(c) 10 kg m-3

(d) 103 kg m-3

Answer. d) 103 kg m-3

### 55: One watt hour contains how many joules?

(a) 3.6 ✕ 108 J

(b) 3.6 ✕ 102 J

(c) 3.6 ✕ 103 J

(d) 10-3 J

Answer. c) 3.6 ✕ 103 J

### 56: Which of the following pairs has the same dimensions?

(a) Specific Heat and Latent Heat

(b) Impulse and Momentum

(c) Surface Tension and Force

(d) Moment of Inertia and Torque

Answer. b) Impulse and Momentum

### 57: The equation of state of some gases can be expressed as Vander wal equation i.e.

(P + a/v2)(V – b) = RT

Where P is the pressure, V is the volume, T is the absolute temperature and a, b, R are constants. The dimensions of ‘a’ are:

(a) [M1L1T-1]

(b) [M1L-5T1]

(c) [M2L5T-1]

(d) [M1L5T-2]

Answer. d) [M1L5T-2]

### 58: Electron volt is a unit of

(a) Charge

(b) Potential difference

(c) Energy

(d) Magnetic Force

Answer. c) Energy

### 59: There are 20 divisions in 4 cm of the main scale. The vernier scale has 10 divisions. The least count of the instrument is

(a) 0.05 cm

(b) 0.5 cm

(c) 5.0 cm

(d) 0.005 cm

Answer. d) 0.005 cm

### Units and Measurements Class 11 MCQs Questions with Answers

### Units and Measurements Class 11 MCQs Questions with Answers

Question 1.

Physical quantities are

(a) quantities such as degrees, radians and steradians

(b) quantities such as length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity

(c) quantities such as pounds, dollars and rupees

(d) quantities such as kilos, pounds and gallons

Answer: (b) quantities such as length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity

#### Question 2. Which of the following pairs has the same dimensions?

(a) specific heat and latent heat

(b) lmpulse and momentum

(c) surface tension and force

(d) moment of lnertia and torque

Answer: (b) lmpulse and momentum

### Question 3.The dimensions of kinetic energy is

(a) [M 2L2T]

(b) [ML 2T]

(c) [ML 2T-2]

(d) [ML 2T-1]

Answer: (c) [ML 2T-2]

#### Question 4. A force F is given by F = at + bt², where t is time. What are the dimensions of a and b?

(a) MLT-1 and MLT0

(b) MLT-3 and ML2T4

(c) MLT-4 and MLT1

(d) MLT-3 and MLT-4

Answer: (d) MLT-3 and MLT-4

#### Question 5. The atmospheric pressure is 106 dyne/cm². What is its value in SI unit?

(a) 105 newton/m²

(b) 106 newton/m²

(c) 104 newton/m²

(d) 103 newton/m²

Answer: (a) 105 newton/m²

#### Question 6. In a system of units if force (F), acceleration (A) and time (T) are taken as fundamentals units then the dimensional formula of energy is

(a) FA2T

(b) FAT2

(c) FA2T

Answer: (b) FAT2

#### Question 7. If force (F), work (W) and velocity (v) are taken as fundamental quantities. What is the dimensional formula of time (T)?

(a) [WFv]

(b) [WFv-1]

(c) [W-1F -1v]

(d) [WF-1v -1]

Answer: (d) [WF-1v -1]

#### Question 8. The dimensions of kinetic energy is same as that of

(a) force

(b) pressure

(c) work

(d) momentum

Answer: (c) work

#### Question 9. Which of the following groups have different dimensions?

(a) Potential difference, EMF, voltage

(b) Pressure, stress, Youngs modulus

(c) Heat, energy, work done

(d) Dipole moment, electric flux, electric field

Answer: (d) Dipole moment, electric flux, electric field

#### Question 10. ML-1T -2 is the dimensional formula of

(a) magnetic induction

(b) self-inductance

(c) electric potential

(d) electric field

Answer: (a) magnetic induction

### Units and Measurements Class 11 MCQ Questions Free PDF | MCQ on Units and Measurements Class 11 pdf with Answers

#### Question 11. What is the dimensional formula of magnetic field?

(a) MT-2A-1

(b) MT-1A-2

(c) M-1L-2TA-1

(d) M-1LTA-2

Answer: (a) MT-2A-1

#### Question 12. Electron volt is a unit of

(a) charge

(b) potential difference

(c) energy

(d) magnetic force

Answer: (c) energy

#### Question 13. The volume of a cube in m³ is equal to the surface area of the cube in m². The volume of the cube is

(a) 64 m³

(b) 216 m³

(c) 512 m³

(d) 196 m³

Answer: (b) 216 m³

#### Question 14. In SI system the fundamental units are

(a) meter, kilogram, second, ampere, Kelvin, mole and candela

(b) meter, kilogram, second, coulomb, Kelvin, mole and candela

(c) meter, Newton, second, ampere, Kelvin, mole and candela

(d) meter, kilogram, second, ampere, Kelvin, mole and lux

Answer: (b) meter, kilogram, second, coulomb, Kelvin, mole and candela

#### Question 15. Which one of the following represents the correct dimensions of the coefficient of viscosity?

(a) [ML-1T-2]

(b) [MLT-1]

(c) [ML-1T-1]

(d) [ML-2T-2]

Answer: (c) [ML-1T-1]

#### Question 16. A particle starting from the origin (0, 0) moves in a straight line in the (x, y) plane. Its coordinates at a later time are the path of the particle makes with the x-axis an angle of

(a) 300

(b) 450

(c) 600

(d) 0

Answer: (c) 600

#### Question 17. Resolution is

(a) a measure of the bias in the instrument

(b) None of these

(c) the smallest amount of input signal change that the instrument can detect reliably

(d) a measure of the systematic errors

Answer: (d) a measure of the systematic errors

#### Question 18. Absolute error of the measurement is

(a) the difference between the individual measurement and the true value of the quantity cubed.

(b) the difference between the individual measurement and the true value of the quantity squared.

(c) the difference between two individual measurements and their mean

(d) the difference between the individual measurement and the true value of the quantity

Answer: (a) the difference between the individual measurement and the true value of the quantity cubed.

#### Question 19. Which of the following units denotes the dimensions [ML2/Q2], where Q represents the electric charge?

(a) Wb/m²

(b) Henry(H)

(c) H/m²

(d) Weber(Wb)

Answer: (b) Henry(H)

#### Question 20. Light year is a unit of

(a) time

(b) distance

(c) sunlight intensity

(d) mass

Answer: (b) distance

### Units and Measurements Class 11 MCQ Questions Free PDF | MCQ on Units and Measurements Class 11 pdf with Answers

### Q1. Out of the following pairs, which one does not have identical dimensions ?

(a) Angular momentum and Planck’s constant

(b) Impulse and momentum

(c) Moment of inertia and moment of a force

(d) Work and torque

Show Answer

(c) Moment of inertia and moment of a force

### Q2. Which of the following physical quantities has different dimensions?

(a) Energy

(b) Watt hour

(c) Momentum

(d) Work

Show Answer

(c) Momentum

### Q3. Identify the pair whose dimensions are equal.

(a) Torque and work

(b) Stress and energy

(c) Force and stress

(d) Force and work

Show Answer

(a) Torque and work

### Q4. Dimensions cannot be used to

(a) check dimensional correctness of a formula

(b) convert units

(c) find value of the constant of proportionality in an equation

(d) deduce a relation among physical quantities

Show Answer

(c) find value of the constant of proportionality in an equation

#### Q5. Two physical quantities whose dimensions are not same, cannot be :

(a) multiplied with each other

(b) divided

(c) added or substracted in the same expression

(d) added together

Show Answer

(c) added or substracted in the same expression

#### Q6. A student measures the distance covered and time taken by a body under free fall which was intially at rest. He uses this data for estimating g, the acceleration due to gravity. If the maximum percentage error in measurement of the distance and the time are e1 and e2 respectively, then the maximum possible percentage error in the estimation of g is

(a) e2 – e2

(b) e2 + 2e2

(c) e2 + e2

(d) e2 – 2e2

Show Answer

(b) e2 + 2e2

#### Q7. The number of significant figures in the distance of one light year , 9.4605 × 1015 m is

(a) thirty

(b) five

(c) four

(d) three

Show Answer

(b) five

#### Q8. The most suitable instrument for measuring the size of an atom is.

(a) Electron microscope

(b) Vernier calliper

(c) Optical Microscope

(d) Screw gauge

Show Answer

(a) Electron microscope

#### Q9. In case of measurement of ‘g’, if error in measurement of length of pendulum is 2%, the percentage error in time period is1 %. The maximum error in measurement of g is

(a) 1 %

(b) 2 %

(c) 4 %

(d) No error

Show Answer

(c) 4 %

#### Q10. The respective number of significant figures for the numbers 23.023, 0.0003 and 2.1 × 10–3 are

(a) 5, 1, 2

(b) 4, 4, 2

(c) 5, 1, 5

(d) 5, 5, 2

Show Answer

(a) 5, 1, 2

#### Q11. Choose the correct statement(s)

(a) Topological sort can be used to obtain an evaluation order of a depending graph.

(b) Evaluation order for a dependency graph dicates the order in which the semantic rules are done

(c) Code generation is independent of the order in which the semantic actions are performed

(d) Both (a) and (b)

Show Answer

(d) Both (a) and (b)

#### Q12. What is the number of significant figures in 0.310×103 ?

(a) 6

(b) 2

(c) 4

(d) 3

Show Answer

(d) 3

#### Q13. Which of the following is not the unit of energy?

(a) watt-hour

(b) electron-volt

(c) N × m

(d) kg × m/sec2

Show Answer

(d) kg × m/sec2

#### Q14. In an experiment the angles are required to be measured using an instrument. 29 divisions of the main scale exactly coincide with the 30 divisions of the vernier scale. If the smallest division of the main scale is half-a-degree (= 0.5°), then the least count of the instrument is

(a) One minute

(b) Half minute

(c) One degree

(d) Half degree

Show Answer

(a) One minute

#### Q15. Electron volt is a unit of

(a) Potential difference

(b) Electric current

(c) Electronic charge

(d) Energy

Show Answer

(d) Energy

#### Q16. A particle starting from the origin (0, 0) moves in a straight line in the (x, y) plane. Its coordinates at a later time are the path of the particle makes with the x-axis an angle of

(a) 300

(b) 450

(c) 600

(d) 0

Show Answer

(c) 600

#### Q17. Resolution is

(a) a measure of the bias in the instrument

(b) None of these

(c) the smallest amount of input signal change that the instrument can detect reliably

(d) a measure of the systematic errors

Show Answer

(d) a measure of the systematic errors

#### Q18. Absolute error of the measurement is

(a) the difference between the individual measurement and the true value of the quantity cubed.

(b) the difference between the individual measurement and the true value of the quantity squared.

(c) the difference between two individual measurements and their mean

(d) the difference between the individual measurement and the true value of the quantity

Show Answer

(a) the difference between the individual measurement and the true value of the quantity cubed.

#### Q19. Which of the following units denotes the dimensions [ML2/Q2], where Q represents the electric charge?

(a) Wb/m²

(b) Henry(H)

(c) H/m²

(d) Weber(Wb)

Show Answer

(b) Henry(H)

#### Q20. Light year is a unit of

(a) time

(b) distance

(c) sunlight intensity

(d) mass

Show Answer

(b) distance

#### Q21. Which one of the following pairs of quantities and their units is a proper match?

(a) Magnetic flux – weber

(b) Capacitance – henry

(c) Impulse – N/sec

(d) Power – farad

Show Answer

(a) Magnetic flux – weber

#### Q22. One second is defined to be equal to

(a) 9192631770 periods of the cesium clock

(b) 1650763.73 periods of the cesium clock

(c) 652189.63 periods of the krypton clock

(d) 1650763.73 periods of the krypton clock

Show Answer

(a) 9192631770 periods of the cesium clock

### Units and Measurements Class 11 MCQ Questions Free PDF | MCQ on Units and Measurements Class 11 pdf with Answers

### Class 11 physics MCQs chapter-wise

Chapter 1 : MCQ on Unit and Measurements

Chapter 2 : Mathematical Methods MCQs

Chapter 3. Motion in plane MCQs

Chapter 4 : Laws of Motion MCQs

Chapter 5 : Gravitation MCQs

Chapter 6 : Machanical properties of solids MCQs

Chapter 7 : Thermal properties of Matter MCQs

Chapter 8 : Sound MCQs

Chapter 9 : Optics MCQs

Chapter 10 : Electrostatics MCQs

Chapter 11 : Electric current through conductors MCQs

Chapter 12 : Magnetism MCQs

Chapter 14 : Electromagnetic waves and communication system MCQs

Chapter 15 : Semiconductors MCQs

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