Which one of the following statements is correct?

• Any energy transfer that does not involve temperature difference in some way is not heat.

• Any energy transfer always requires a temperature difference.

• On heating the length and volume of the object remain exactly the same.

• Whenever there is a temperature difference, heat is the only way of energy transfer.

If T is the time period of an oscillating pendulum, which one of the following statements is NOT correct?

• The motion repeats after time T only once

• T is the least time after which motion repeats itself

• The motion repeats itself after nT, where n is a positive integer

• T remains the same only for small angular displacements

If an object moves with constant velocity, then which one of the following statements is NOT correct?

• Its motion is along a straight line

• Its speed changes with time

• Its acceleration is zero

• Its displacement increases linearly with time

4.

An object is moving with uniform acceleration a. Its initial velocity is u and after time t its velocity is v. The equation of its motion is v = u + at. The velocity (along y-axis) time (along x-axis) graph shall be a straight line

• passing through origin

• with x-intercept u

• with y-intercept u

• with slope u

What is the net force experienced by a bar magnet plated in a uniform magnetic field?

• Zero

• Depends upon length of the magnet

• Never zero

• Depends upon temperature

Which one of the following has maximum inertia?

• An atom

• A molecule

• A one-rupee coin

• A cricket ball

Which one of the following is the value of 1 kWh of energy converted into joules?

• 1.8 x 10⁶ J

• 3.6 x 10⁶ J

• 6.0 x 10⁶ J

• 7.2 x 10⁶ J

Which one of the following statements about gravitational force is NOT correct?

• It is experienced by all bodies in the universe

• It is a dominant force between celestial bodies

• It is a negligible force for atoms

• It is same for all pairs of bodies in our universe

Whether an object will float or sink in a liquid, depends on

• mass of the object only

• mass of the object and density of liquid only

• difference in the densities of the object and liquid

• mass and shape of the object only

Which one of the following devices is non-ohmic?

• Conducting copper coil

• Electric heating coil

• Semi conductor diode

• Rheostat