Question

What is the difference between laser and normal light?
(A) Both light are polarized
(B) Normal light is polarized but laser light is not
(C) Both light are not polarized
(D) Normal light is not polarized but laser is polarized

Answer 1

Hint :Polarization of light means transmitting a light through a material by which the light vibrating in various directions is restricted to a single plane. By polarization, the intensity of the light decreases, but is focused in one direction.

Complete Step By Step Answer:
We know that light travels in the form of vibrations in various directions.
The vibrations of light are always perpendicular to the direction of propagation of light, but they can be in a single random perpendicular plane or in multiple perpendicular planes.
Normal light is incoherent and divergent. It spreads in all the directions. Due to this property, we get higher intensity from normal light but it is not focused.
As normal light travels in all directions, we can understand that it vibrates in different planes simultaneously.
Hence, due to this divergent property, we can say that normal light is polarized light.
Now, if normal light is passed through a polarizer, the vibrations which are in line with the axis of the polarizer are only allowed to pass. Rest all the vibrations are absorbed in the polarizer
Now, the light coming out of the polarizer has vibrations in only one direction.
This makes the polarized light convergent or focused as well as coherent.
As we know that laser light is also a focused, convergent, and coherent light, we can derive that laser light is a polarized light.
Hence, the final answer is that normal light is not polarized but laser light is polarized.
The correct answer is Option (D).

Note :
To understand the question, we must understand the concept of polarization first. Also the above derived result may prove wrong in some of the special cases, however generally, the normal light is not polarized while laser light is polarized.