1 Units and Measurement MCQ Practice

Q.1    The dimensional formula for the modulus of rigidity is –

           (1) ML2 T–2                  (2) ML–1T–3

           (3) ML–2T–2                (4) ML–1T–2

Q.2     Out of the following, the only pair that does not have identical dimensions is –

           (1) Angular momentum and Planck’s constant

           (2) Moment of inertia and moment of a force

           (3) Work and torque

           (4) Impulse and momentum

Q. 3 A physcial quantity x depends on quantities y and z as follows: x = Ay + B tan Cz, where A, B and C  are constants. Which of the following do not have the same dimensions

           (1) x and B                   (2) C and z–1

           (3) y and B/A               (4) x and A

Q.4 The velocity of a freely falling body changes as gphq where g is acceleration due to gravity and h is the height. The values of p and q are –

           (1) 1, 1/2                       (2) 1/2, 1/2

           (3) 1/2, 1                       (4) 1, 2

Q.5     If energy (E), velocity (v) and force (F) be taken as fundamental quantity, then what are the dimensions of mass

           (1) Ev2                         (2) Ev–2

           (3) Fv–1                        (4) Fv–2

Q.6 Which of the following units denotes the dimensions ML2 /Q2, where Q denotes the electric charge

           (1) H/m2                        (2) Weber (Wb)

           (3) Wb/ m2                    (4) Henry (H)

Q.7 A body travels uniformly a distance of

           (13.8 ± 0.2) m in a time (4.0 ± 0.3) s. Its velocity with error limits is

           (1) (3.5 ± 0.6) m s–1     (2) (3.5 ± 0.3) m s–1

           (3) (6.1 ± 0.6) m s–1     (4) (6.1 ± 0.3) m s–1

Q.8 Which of the following group have different dimension

           (1) Potential difference, EMF, voltage           

           (2) Pressure, stress, Young’s modulus

           (3) Heat, energy, work done               

           (4) Dipole moment, electric flux, electric field

Q.9   The mass and volume of a body are 4.237 g and 2.5 cm3, respectively. The density of the material of the body in correct significant figures is –

           (1) 1.6948 g cm–3           (2) 1.69 g cm–3

           (3) 1.7 g cm–3                   (4) 1.695 g cm–3

Q.10   Young’s modulus of steel is 1.9 × 1011 N/m2. When expressed in CGS units of dynes/cm2, it will be equal to (1N = 105dyne, 1m2 = 104 cm2)

           (1) 1.9 × 10^10                    (2) 1.9 × 10^11

           (3) 1.9 × 10^12                    (4) 1.9 × 10^13