Choose from the following the best the best statement about specific heat of a substance.

A 90-kg man climbs up a flight of steps 5.5 m high in 30 s. What is the power developed by the man?

In order to explain the nature of light using the experimental results known in his time, Neils Bohr came up with a theory called the complementarity principle. Which of the following is the best explanation of this principle?

What is the increase in potential energy of a boy who does 80 J of work in climbing a flight of stairs?

Which of the following statement is true of the gravitational force when the distance between two objects decreases?

The intensity of a sound is a measure of

According to Newton’s second law of motion

Which of the following is not necessarily true about the image produced by a pinhole camera?  

If the speed of sound in air at 0o C is 330 m/s, what is its speed at 60o C?

Energy released from the interior of the earth is called