Question

Read the assertion and reason carefully to mark the correct option out of the options given below.
Assertion : The unpolarized light and polarized light can be distinguished from each other by using polaroid.
Reason : A polaroid is capable of producing plane polarized beams of light.

• A. Both assertion and reason are true, and the reason is the correct explanation of assertion.
• B. Both assertion and reason are true, but reason is not the correct explanation of the assertion.
• C. Assertion is true, but reason is false.
• D. Assertion and reason, both are false.

Answer 1

The correct option is A Both assertion and reason are true, and the reason is the correct explanation of assertion.

When a polaroid is rotated in the path of unpolarized light, the intensity of light transmitted from polaroid remains undiminished (because unpolarized light contains waves vibrating in all possible planes with equal probability).

However, when the polaroid is rotated in path of plane polarized light, its intensity will vary from maximum (when the vibrations of the plane polarized light are parallel to the transmission axis of the polaroid) to minimum (when the direction of the vibrations becomes perpendicular to the axis of the crystal).

Thus, using polaroid we can easily verify that whether the incident light is polarized or not.

Hence, $\left(A\right)$ is the correct answer.

$\begin{array}{c}\text{Why this question?}\\ \text{To understand the basics of polarization}\end{array}$