Why is terminal voltage of a cell less than its emf?

State the factors on which the current sensitivity of a galvanometer is increased.

The motion of copper plate is damped when it is allowed to oscillate between the two poles of a magnet what is the cause of this damping?

Draw a diagram depicting oscillating electric and magnetic field of an electromagnetic wave.

How does focal length of a lens change when red light is replaced by blue light?

Does the stopping potential in photoelectric emission depend upon
(i) the intensity of the incident radiation in a photocell
(ii) the frequency of the incident radiation?

What is the reason for using lighter nuclei as moderators?

How does the peacock feathers get colouration?

No interference pattern is detected when two coherent sources are infinitely close to each other. Why?

What do you mean by communication?