Deepak Scored 45->99%ile with Bounce Back Crack Course. You can do it too!

What happens to the intensity of light from a bulb

Question:

What happens to the intensity of light from a bulb if the distance from the bulb is doubled? As a laser beam travels across the length of a room, its intensity essentially remains constant. What geometrical characteristics of the LASER beam is responsible for the constant intensity which is missing in the case of light from the bulb?

Solution:

When the distance is doubled, the intensity of light becomes one-fourth.

Following are the geometrical characteristics of the LASER:

(a) unidirectional

(b) monochromatic

(c) coherent light