When lighting a bulba in a dark room, light spreads the whole room quickly. Give reason.

When light is refracted into a denser medium

Sparking occurs in the switches when light is put off. Given reason.

When we enter a dark room, pupil of our eye ………………. .

Give the value of one light year.

When the intensity of a light source is increased.

When light is refracted which of the following does not change?

When a proton is released from rest in a room, it starts with an initial acceleration a_0 towards west. When it is projected towards north with a speed nu_0 it moves with an initial acceleration 2a_0 toward west. The electric and magnetic fields in the room are