# Units and Measurement MCQ Class 11 Physics

Please refer to Chapter 2 Units and Measurement MCQ Class 11 Physics with answers below. These multiple-choice questions have been prepared based on the latest NCERT book for Class 11 Physics. Students should refer to MCQ Questions for Class 11 Physics with Answers to score more marks in Grade 11 Physics exams. Students should read the chapter Units and Measurement and then attempt the following objective questions.

**MCQ Questions Class 11 Physics Chapter 2 Units and Measurement**

The Units and Measurement MCQ Class 11 Physics provided below covers all important topics given in this chapter. These MCQs will help you to properly prepare for exams.

**Question.** Multiply 107.88 by 0.610 and express the result with correct number of significant figures.

(a) 65.8068

(b) 65.807

(c) 65.81

(d) 65.8

**Answer**

D

**Question.** The dimensions of magnetic moment are

(a) [L^{2} A^{1}]

(b) [L^{2} A^{–1}]

(c) [L^{2} / A^{3}]

(d) [LA^{2}]

**Answer**

A

**Question.** The mass of the liquid flowing per second per unit area of cross-section of the tube is proportional to (pressure difference across the ends)^{n }and (average velocity of the liquid)^{m}. Which of the following relations between m and n is correct?

(a) m = n

(b) m = – n

(c) m^{2} = n

(d) m = – n^{2}

**Answer**

** Question. The dimensional formula for relative density is**(a) [M L

^{–3}]

(b) [M

^{0}L

^{–3}]

(c) [M

^{0}L

^{0}T

^{–1}]

(d) [M

^{0}L

^{0}T

^{0}]

**Answer**

D

**Question.** The dimensions of pressure gradient are

(a) [ML^{–2} T^{–2}]

(b) [ML^{–2} T^{–1}]

(c) [ML^{–1} T^{–1}]

(d) [ML^{–1} T^{–2}]

**Answer**

A

**Question.** The velocity of a body which falls under gravity varies as g^{a} h^{b}, where g is acc. due to gravity and h is the height. The values of a and b are

(a) a = 1, b = 1/2

(b) a = b = 1

(c) a = 1/2, b = 1

(d) a = 1/2; b = 1/2

**Answer**

D

**Question.** Which of the following is a derived physical quantity?

(a) Mass

(b) Velocity

(c) Length

(d) Time

**Answer**

B

**Question.** N kg^{–1} is the unit of

(a) velocity

(b) force

(c) acceleration

(d) None of these

**Answer**

C

**Question.** The Richardson equation is given by I = AT^{2}e^{–B/kT}. The dimensional formula for AB^{2} is same as that for

(a) I T^{2}

(b) kT

(c) I k^{2}

(d) I k^{2}/T

**Answer**

C

**Question.** Let Q denote the charge on the plate of a capacitor of capacitance C. The dimensional formula for**Q ^{2}/Q is**

(a) [L

^{2}M

^{2}T]

(b) [LMT

^{2}]

(c) [L

^{2}MT

^{-2}]

(d) [L

^{2}M

^{2}T

^{2}]

**Answer**

C

**Question.** The unit of current in C.G..S. system is

(a) 10 A

(b) 1/10 A

(c) 1/100 A

(d) 1/1000 A

**Answer**

A

**Question.** The velocity v of a particle at time t is given by**V = at + b/t+c** **The dimensions of a, b c are respectively**

(a) [LT^{–2}], [L], [T]

(b) [L^{2}], [T] and [LT^{2}]

(c) [LT^{2}], [LT] and [L]

(d) [L], [LT] and [T^{2}]

**Answer**

A

**Question.** Dimensions of impulse are

(a) [MLT^{-1}]

(b) [MLT^{2} ]

(c) [MT^{-2} ]

(d) [ML^{-1}T^{-3 }]

**Answer**

A

**Question.** The dimensions of Rydberg’s constant are

(a) [M0 L^{–1} T]

(b) [MLT^{–1}]

(c) [M^{0} L^{–1} T^{0}]

(d) [ML^{0} T^{2}]

**Answer**

C

**Question.** Error in the measurement of radius of a sphere is 1%. Then error in the measurement of volume is

(a) 1%

(b) 5%

(c) 3%

(d) 8%

**Answer**

C

** Question. The solid angle sustended by the total surface area of a sphere, at the centre is**(a) 4p

(b) 2p

(c) p

(d) 3p

**Answer**

A

**Question.** When 97.52 is divided by 2.54, the correct result is

(a) 38.3937

(b) 38.394

(c) 38.39

(d) 38.4

**Answer**

D

**Question.****Unit of latent heat is**

(a) J Kg^{–1}

(b) J mol^{–1}

(c) N Kg^{–1}

(d) N mol^{–1}

**Answer**

A

**Question.****Dyne-sec is the unit of**

(a) momentum

(b) force

(c) work

(d) angular momentum

**Answer**

A

**Question. Which of the following do not have the same dimensional formula as the velocity? Given that μ _{0} = permeability of free space, ∈_{0} = permittivity of free space, n = frequency, λ = wavelength, P = pressure, r = density, w = angular frequency, k = wave number,**

**Answer**

D

**Question. A cube has numerically equal volume and surface area. The volume of such a cube is**

(a) 1000 unit

(b) 200 unit

(c) 216 unit

(d) 300 unit

**Answer**

C

**Question.** **The heat generated in a circuit is given by Q = I ^{2} Rt, where I is current, R is resistance and t is time. If the percentage errors in measuring I, R and t are 2%, 1% and 1% respectively, then the maximum error in measuring heat will be**

(a) 2%

(b) 3%

(c) 4%

(d) 6%

**Answer**

D

**Question. Specific gravity has ………… dimensions in mass, ………… dimensions in length and ………… dimensions in time.**

(a) 0, 0, 0

(b) 0, 1, 0

(c) 1, 0, 0

(d) 1, 1, 3

**Answer**

A

**Question. If x = a – b, then the maximum percentage error in the measurement of x will be**

**Answer**

C

**Question. If time T, acceleration A and force F are regarded as base units, then the dimensional formula of work is**

(a) [FA]

(b) [FAT]

(c) [FAT^{2} ]

(d) [FA^{2}T]

**Answer**

C

**Question. The thrust developed by a rocket-motor is given by F = mv + A(P _{1} – P_{2} ) where m is the mass of the gas ejected per unit time, v is velocity of the gas, A is area of cross section of the nozzle, P_{1 }and P_{2} are the pressures of the exhaust gas and surrounding atmosphere. The formula is dimensionally**

(a) correct

(b) wrong

(c) sometimes wrong, sometimes correct

(d) Data is not adequate

**Answer**

A

**Question. The density of a material in CGS system of units is 4g/cm ^{3}. In a system of units in which unit of length is 10 cm and unit of mass is 100 g, the value of density of material will be**

(a) 0.4

(b) 40

(c) 400

(d) 0.04

**Answer**

B

**Question. If E, m, J and G represent energy, mass, angular momentum and gravitational constant respectively, then the dimensional formula of EJ ^{2} /m^{5}G^{2} is**

(a) angle

(b) length

(c) mass

(d) time

**Answer**

A

**Question.** **The density of a cube is measured by measuring its mass and length of its sides. If the maximum error in the measurement of mass and length are 4% and 3% respectively, the maximum error in the measurement of density will be**

(a) 7%

(b) 9%

(c) 12%

(d) 13%

**Answer**

D

**Question.** **A vernier calliper has 20 divisions on the vernier scale, which coincide with 19 on the main scale. The least count of the instrument is 0.1 mm. The main scale divisions are of**

(a) 0.5 mm

(b) 1 mm

(c) 2 mm

(d) 1/4 mm

**Answer**

C

**Question. In a vernier callipers, ten smallest divisions of the vernier scale are equal to nine smallest division on the main scale. If the smallest division on the main scale is half millimeter, then the vernier constant is**

(a) 0.5 mm

(b) 0.1 mm

(c) 0.05 mm

(d) 0.005 mm

**Answer**

C

**Question. The pitch of the screw gauge is 0.5 mm. Its circular scale contains 50 divisions. The least count of the screw gauge is**

(a) 0.001 mm

(b) 0.01 mm

(c) 0.02 mm

(d) 0.025 mm

**Answer**

B

**Question. Which one of the following has the same dimension as that of time, if R is resistance, L inductance and C is capacitance?**

(a) RC

(b) √LC

(c) L/R

(d) All of the above

**Answer**

B

**Question. The pressure on a square plate is measured by measuring the force on the plate and length of the sides of the plate by using the formula P = F / 2l . If the maximum errors in the measurement of force and length are 4% and 2% respectively, then the maximum error in the measurement of pressure is**

(a) 1%

(b) 2%

(c) 8%

(d) 10%

**Answer**

C

**Question. If I is the moment of inertia and ϖ the angular velocity, what is the dimensional formula of rotational kinetic energy** **(1/2) I ϖ ^{2} ?**

(a) [ML

^{2}T

^{-1}]

(b) [M

^{2}L

^{-1}T

^{-2}]

(c) [ML

^{2}T

^{-2}]

(d) [M

^{2}L

^{-1}T

^{-2}]

**Answer**

C

**Question. The equation of a wave is given by**

**linear velocity. The dimensions of K will be**

(a) [T^{2}]

(b) [T^{–1}]

(c) [T]

(d) [L T]

**Answer**

C

**Question. In the equation X = 3YZ ^{2}, X and Z are dimensions of capacitance and magnetic induction respectively. In MKSQ system, the dimensional formula for Y is**

(a) [M

^{–3}L

^{–2}T

^{–2}Q

^{–4}]

(b) [M L

^{–2}]

(c) [M

^{–3}L

^{–2}Q

^{4}T

^{8}]

(d) [M

^{–3}L

^{–2}Q

^{4}T

^{4}]

**Answer**

D

**Question. The dimensions of a rectangular block measured with callipers having least count of 0.01 cm are 5 mm × 10 mm × 5 mm. The maximum percentage error in the measurement of the volume of the block is**

(a) 5%

(b) 10%

(c) 15%

(d) 20%

**Answer**

A

**Question. The frequency of vibration of a string is given by f = n/2L √T/m where T is tension in the string, L is the length, n is number of harmonics. The dimensional formula for m is**(a) [M

^{0}L T]

(b) [M

^{1}L

^{–1}T

^{–1}]

(c) [M

^{1}L

^{–1}T

^{0}]

(d) [M

^{0}L T

^{–1}]

**Answer**

C

**Question. Suppose the kinetic energy of a body oscillating with amplitude A and at a distance x is given by**

**The dimensions of B are the same as that of**

(a) work/time

(b) work × distance

(c) work/distance

(d) work × time

**Answer**

B

**Question. A force is given by F = at + bt ^{2}, where t is time, the dimensions of a and b are**

(a) [M L T

^{–4}] and [M L T

^{–1}]

(b) [M L T

^{–1}] and [M L T

^{0}]

(c) [M L T

^{–3}] and [M L T

^{–4}]

(d) [M L T

^{–3}] and [M L T

^{0}]

**Answer**

C

**Question. If the dimensions of a physical quantity are given by M ^{a} L^{b} T^{c}, then the physical quantity will be**

(a) velocity if a = 1, b = 0, c = – 1

(b) acceleration if a = 1, b = 1, c = – 2

(c) force if a = 0, b = – 1, c = – 2

(d) pressure if a = 1, b = – 1, c = – 2

**Answer**

D

**Question. Consider the following pairs of quantities****1. Young’s modulus; pressure****2. Torque; energy****3. Linear momentum; work****4. Solar day; light year.****In which cases are the dimensions, within a pair, same?**

(a) 1 and 3

(b) 1 and 4

(c) 1 and 2

(d) 2 and 4

**Answer**

C

**Question. The time of reverberation of a room A is one second. What will be the time (in seconds) of reverberation of a room, having all the dimensions double of those of room A?**

(a) 2

(b) 4

(c) 2/1

(d) 1

**Answer**

**Question. Two full turns of the circular scale of a screw gauge cover a distance of 1mm on its main scale. The total number of divisions on the circular scale is 50. Further, it is found that the screw gauge has a zero error of – 0.03 mm. While measuring the diameter of a thin wire, a student notes the main scale reading of 3 mm and the number of circulr scale divisions in line with the main scale as 35. The diameter of****the wire is**

(a) 3.32 mm

(b) 3.73 mm

(c) 3.67 mm

(d) 3.38 mm

**Answer**

D

**Question. In an experiment four quantities a, b, c and d are measured with percentage error 1%, 2%, 3% and 4% respectively. Quantity P is calculated as follows**

**% error in P is**

(a) 10%

(b) 7%

(c) 4%

(d) 14%

**Answer**

D

**Question. The dimensions of voltage in terms of mass (M), length (L) and time (T) and ampere (A) are**(a) [ML

^{2}T

^{–2}A

^{–2}]

(b) [ML

^{2}T

^{3}A

^{–1}]

(c) [ML

^{2}T

^{–3}A

^{1}]

(d) [ML

^{2}T

^{–3}A

^{–1}]

**Answer**

D

**Question. The dimensions of magnetic field in M, L, T and C (coulomb) are given as**

(a) [MLT^{–1} C^{–1}]

(b) [MT^{2} C^{–2}]

(c) [MT^{–1} C^{–1}]

(d) [MT^{–2} C^{–1}]

**Answer**

C

**Question. What is the fractional error in g calculated from T = 2π√ l / g ? Given fractional errors in T and l are ± x and ± y respectively.**

(a) x + y

(b) x – y

(c) 2x + y

(d) 2x – y

**Answer**

C

**Question.** **In a simple pendulum experiment for the determination of acceleration due to gravity, time period is measured with an accuracy of 0.2% while length was measured with an accuracy of 0.5%. The percentage accuracy in the value of g so obtained is**

(a) 0.25%

(b) 0.7%

(c) 0.9%

(d) 1.0%

**Answer**

C

**Question. The resistance R of a wire is given by the relation R = Pl/πr ^{2}**

**Percentage error in the measurement of r, l and r is 1%, 2% and 3% respectively. Then the percentage error in the measurement of R is :**

(a) 6

(b) 9

(c) 8

(d) 10

**Answer**

B

**Question. Which of the following is the unit of molar gas constant?**

(a) JK^{–1} mol^{–1}

(b) Joule

(c) JK^{–1}

(d) J mol^{–1}

**Answer**

A

**Question.** **The dimensional formula of velocity gradient is**

(a) [M^{0}L^{0}T^{-1}]

(b) [MLT^{1}]

(c) [ML^{0}T^{-1}]

(d) [M^{0}LT^{-2} ]

**Answer**

A

**Question.** **The dimensional formula of couple is**

(a) [ML^{2}T^{-2} ]

(b) [MLT^{2} ]

(c) [ML^{-1}T^{-3} ]

(d) [ML^{-2}T^{-2} ]

**Answer**

A

**Question.** **Diameter of a steel ball is measured using a Vernier callipers which has divisions of 0.1 cm on its main scale (MS) and 10 divisions of its vernier scale (VS) match 9 divisions on the main scale. Three such measurements for a ball are given below:**

**If the zero error is – 0.03 cm, then mean corrected diameter is**

(a) 0.52 cm

(b) 0.59 cm

(c) 0.56 cm

(d) 0.53 cm

**Answer**

B

**Question.** **The period of oscillation of a simple pendulum is T = 2π √L/g Measured value of L is 20.0 cm known to 1 mm accuracy and time for 100 oscillations of the pendulum is found to be 90 s using a wrist watch of 1s resolution. The accuracy in the determination of g is**

(a) 1%

(b) 5%

(c) 2%

(d) 3%

**Answer**

D

**Question. What are the dimensions of permeability ?**

(a) [M^{1}L^{1}T^{1}A^{–2}]

(b) [M^{1}L^{1}T^{–2}A^{–2}]

(c) [M^{2}L^{2}T^{1}A^{0}]

(d) [M^{1}L^{2}T^{2}A^{–2}]

**Answer**

B

**Question. The physical quantity having the dimensions [M ^{–1}L^{–3}T^{3}A^{2}] is**

(a) resistance

(b) resistivity

(c) electrical conductivity

(d) electromotive force

**Answer**

C

**Question. Density of liquid is 16.8 g cm ^{–3}. Its value in the International System of Units is**

(a) 16.8 kgm

^{-3}

(b) 168 kgm

^{-3}

(c) 1680 kgm

^{-3}

(d) 16800 kgm

^{-3}

**Answer**

D

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