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A parallel plate capacitor is charged and then charging battery is disconnected. If the plates are now pulled apart with insulated handles

A positive charge is moved from low potential point A to a high potential point B. Then the electric potential energy

Two waves of wavelength 50 cm and 51 cm produced 12 beats per second. The velocity of sound is

A heavy rope is suspended from rigid support. A wave pulse is set up at the lower end. Then

An object on a spring vibrates in a simple harmonic motion at a frequency of 4 hertz and an amplitude of 8 cm. If the mass of the object is 200 g, the spring constant is

The root mean square speed of molecules of a gas is 1260 m/s. The average speed of the gas molecules is

An ideal engine whose efficiency is 40%, receives heat at 500 K. If required efficiency is 50%, then intake temperature for the same exhaust temperature is

Choose the correct statement.

In a thermodynamic process, pressure of fixed mass of a gas is changed in such a manner that the gas releases 20 J of heat and 8 J of work is done on the gas. If initial internal energy of the gas was 40 J, what will be final internal energy?

Two rain drops reach earth from clouds with different terminal velocities having ratio 9 : 4. Then the ratio of their volumes is

If work done in increasing the size of rectangular soap film with dimensions 8 cm × 3.75 cm to 10 cm × 6 cm is 2 × 10^–4 J. The surface tension of film in newton per meter is

A wire can be broken by a load of 20 kg-wt. The force required to break wire of same material with twice the diameter will be

The height at which the weight of an object becomes (1/16)^thof its weight on the surface of earth is (R is radius of earth)

A body is released from height equal to radius R of the earth. The velocity of body with which it will strike the earth surface is

A flywheel of mass 50 kg and radius of gyration about its axis of rotation of 0.5 m is acted upon by a constant torque of 12.5 N m. Its angular velocity at t = 5 s is

Two bodies of mass 10 kg and 2 kg are moving with velocities m/s and m/s respectively. The velocity of their centre of mass is

In stable equilibrium position, a body has

A particle moves along x axis from x = 1 m to x = 3 m under the effect of the force F = 3x² – 2x + 5 N. Work done in process is