Question

What can you see in a completely dark room ? If you switch on an electric bulb in this darkroom as a light source, explain how you could now see :

(a) the electric bulb. (b) a piece of white paper.

Answer 1

When we see in a completely dark room, we are not able to see anything because there is no light in the dark room. 

(a) We can see bulb due to the light emitted by the bulb. 

(b) We can see a piece of white paper because it reflects the light from the bulb falling on it.