Which of the following statement(s) about electromagnetic waves, sound waves and water waves is/are correct?

1. They exhibit reflection.

2. They carry energy.

3. They exert pressure.

4. They can travel in vacuum.

Thermal capacity of a body depends on the

Which one of the following metal is used in the filaments of photoelectric cells that converts light energy into electric energy?

A thin disc and a thin ring, both have mass M and radius R. Both rotate about axes through their centre of mass and are perpendicular to their surfaces at the same angular velocity. Which one of the following statements is correct?