The dimensional formula for inductance is

• [ML²T^-2A^-2]

• [ML²TA^-2]

• [ML²T^-1A^-2]

• [ML²T^-2A^-1]

A bullet moving with a speed of 100 ms^-1 can just penetrate two planks of equal thickness. Then, the number of such planks penetrated by the same bullet when the speed is doubled will be

• 6

• 10

• 4

• 8

Two bodies of masses 1 kg and 2 kg have equal momentum. Then, the ratio of their kinetic energies is

• 2 : 1

• 3 : 1

• 1 : 3

• 1 : 1

The physical quantity having the same dimensions as Planck's constant h is

• linear momentum

• angular momentum

• Boltzmann constant

• force

A balloon is rising vertically up with a velocity of 29 ms^-1 .A stone is dropped from it and it reaches the ground in 10 seconds. The height of the balloon when the stone was dropped from it is (g = 9.8ms^-1)

• 400 m

• 150 m

• 100 m

• 200 m

SI unit of permittivity is

• C²m²N²

• C²m^-2N^-1

• C²m²N^-1

• C^-1m²N^-2

Two equal forces (P each) act at a point inclined to each other at an angle of120°. The magnitude of their resultant is

• P/2

• P/4

• P

• 2P

When a body moves in a circular path, no work is done by the force since

• force and displacement are perpendicular to each other

• the force is always away from the centre

• there is no displacement

• there is no net force

The difference between the apparent frequency of a source of sound as perceived by the observer during its approach and recession is 2% of the frequency of the source. If the speed of sound in air is 300 ms^-1, the velocity of the source is

• 1.5 ms^-1

• 12 ms^-1

• 6 ms^-1

• 3 ms^-1

Curie-Weiss law is obeyed by iron

• at Curie temperature only

• at all temperatures

• below Curie temperature

• above Curie temperature