CBSE Class 11 Physics Units And Measurement Assignment

Question. The unit of thermal conductivity is
(a) W m^–1 K^–1
(b) J m K^–1
(c) J m^–1 K^–1
(d) W m K^–1
Answer. A

Question. The damping force on an oscillator is directly proportional to the velocity. The units of the constant of proportionality are
(a) kg m s^–1
(b) kg m s^–2
(c) kg s^–1
(d) kg s 
Answer. C

Question. The unit of permittivity of free space, e₀, is
(a) coulomb/newton-metre
(b) newton-metre²/coulomb²
(c) coulomb²/newton-metre²
(d) coulomb²/(newton-metre)²
Answer. C

Question. A screw gauge has least count of 0.01 mm and there are 50 divisions in its circular scale. The pitch of the screw gauge is
(a) 0.01 mm
(b) 0.25 mm
(c) 0.5 mm
(d) 1.0 mm
Answer. C

Question. A student measured the diameter of a small steel ball using a screw gauge of least count 0.001 cm. The main scale reading is 5 mm and zero of circular scale division coincides with 25 divisions above the reference level. If screw gauge has a zero error of –0.004 cm, the correct diameter of the ball is
(a) 0.521 cm
(b) 0.525 cm
(c) 0.053 cm
(d) 0.529 cm 
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 P = a³ b² / cd . % error in P is
(a) 7%
(b) 4%
(c) 14%
(d) 10%
Answer. C

Question. A student measures the distance traversed in free fall of a body, initially at rest, in a given time. He uses this data to estimate g, the acceleration due to gravity. If the maximum percentage errors 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

Question. If the error in the measurement of radius of a sphere 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

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 lengths are 3% and 2% respectively, the maximum error in the measurement of density would be
(a) 12%
(b) 14%
(c) 7%
(d) 9%. 
Answer. D

Question. Percentage errors in the measurement of mass and speed are 2% and 3% respectively. The error in the estimate of kinetic energy obtained by measuring mass and speed will be
(a) 8%
(b) 2%
(c) 12%
(d) 10%. 
Answer. A

Question. A certain body weighs 22.42 g and has a measured volume of 4.7cc. The possible error in the measurement of mass and volume are 0.01 g and 0.1 cc. Then maximum error in the density will be
(a) 22%
(b) 2%
(c) 0.2%
(d) 0.02%.
Answer. B

Question. Taking into account of the significant figures, what is the value of 9.99 m – 0.0099 m?
(a) 9.9801 m
(b) 9.98 m
(c) 9.980 m
(d) 9.9 m 
Answer. B

Question. Dimensions of stress are
(a) [MLT^–2]
(b) [ML²T^–2]
(c) [ML⁰T^–2]
(d) [ML^–1 T^–2]
 Answer. D

Question. The pair of quantities having same dimensions is
(a) Impulse and Surface Tension
(b) Angular momentum and Work
(c) Work and Torque
(d) Young’s modulus and Energy
Answer. C

Question. The dimensions of (μ₀ε₀)^–1/2 are
(a) [L^1/2T^–1/2]
(b) [L^–1T]
(c) [LT^–1]
(d) [L^1/2T^1/2]
Answer. C

Question. The dimension of 1/2 ε₀ E² ,where e0 is permittivity of free space and E is electric field, is
(a) ML²T^–2
(b) ML^–1T^–2
(c) ML²T^–1
(d) MLT^–1
Answer. B

Question. If the dimensions of a physical quantity are given by M^aL^bT^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. Which two of the following five physical parameters have the same dimensions ?
1. energy density
2. refractive index
3. dielectric constant
4. Young’s modulus
5. magnetic field
(a) 1 and 4
(b) 1 and 5
(c) 2 and 4
(d) 3 and 5 
Answer. A

Question. Dimensions of resistance in an electrical circuit, in terms of dimension of mass M, of length L, of time T and of current I, would be
(a) [ML²T^–2]
(b) [ML²T^–1I^–1]
(c) [ML²T^–3I^–2]
(d) [ML²T^–3I^–1] 
Answer. C

Question. The ratio of the dimensions of Planck’s constant and that of moment of inertia is the dimensions of
(a) time
(b) frequency
(c) angular momentum
(d) velocity.
Answer. B

Question. The dimensions of universal gravitational constant are
(a) [M^–1L³T^–2]
(b) [ML²T^–1]
(c) [M^–2L³T^–2]
(d) [M^–2L²T^–1] 
Answer. A

Question. The dimensions of Planck’s constant equals to that of
(a) energy
(b) momentum
(c) angular momentum
(d) power. 
Answer. C

Question. Which pair do not have equal dimensions ?
(a) Energy and torque
(b) Force and impulse
(c) Angular momentum and Planck’s constant
(d) Elastic modulus and pressure. 
Answer. B

Question. The dimensions of impulse are equal to that of
(a) pressure
(b) linear momentum
(c) force
(d) angular momentum 
Answer. B

Question. Which of the following dimensions will be the same as that of time?
(a) L/R
(b) C/L
(c) LC
(d) R/L
Answer. A

Question. The dimensions of RC is
(a) square of time
(b) square of inverse time
(c) time
(d) inverse time. 
Answer. C

Question. Which of the following has the dimensions of pressure?
(a) [MLT^–2]
(b) [ML^–1T^–2]
(c) [ML^–2T^–2]
(d) [M^–1L^–1] 
Answer. B

Question. Of the following quantities, which one has dimensions different from the remaining three ?
(a) Energy per unit volume
(b) Force per unit area
(c) Product of voltage and charge per unit volume
(d) Angular momentum.
Answer. D

Question. The dimensional formula of magnetic flux is
(a) [M⁰L^–2T^–2A^–2]
(b) ML⁰T^–2A^–2]
(c) [ML²T^–2A^–1]
(d) [ML²T^–1A^3] 
Answer. C

Question. The dimensional formula of permeability of free space m0 is
(a) [MLT^–2A^–2]
(b) [M⁰L¹T]
(c) [M⁰L²T^–1A²]
(d) none of these. 
Answer. A

Question. According to Newton, the viscous force acting between liquid layers of area A and velocity gradient  Δv/ΔZ is given by F = −η Δv/ΔZ  , where h is constant called coefficient of viscosity. The dimensional formula of h is
(a) [ML^–2T^–2]
(b) [M⁰L⁰T⁰]
(c) [ML²T^–2]
(d) [ML^–1T^–1]
Answer. D

Question. Dimensional formula of self inductance is
(a) [MLT^–2A^–2]
(b) [ML²T^–1A^–2]
(c) [ML²T^–2A^–2]
(d) [ML²T^–2A^–1]
Answer. C

Question. The dimensional formula of torque is
(a) [ML²T^–2]
(b) [MLT^–2]
(c) [ML^–1T^–2]
(d) [ML^–2T^–2]
Answer. A