Which of the following is a good definition of power?

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

The equation connecting the position (x) and time (t) of a moving object is x = 2.2 t where x is measured in m and time in s. Which of the following is/are true of this object? (i)    The object has no acceleration (ii)   The object changes its position by 2.2 m every second (iii)  The object has a uniform speed of 2.2 m/s

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

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?

Which of the following is NOT a renewable source of energy?

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?

The critical angle for total internal reflection is a:

When total internal reflection happens at a plastic-air interface 

The figure below shows two vibrating particles. What is the phase difference between the two particles?