Question

Assertion (A) : The flim which appears bright in reflected system will appear dark in the transmitted system and vice-versa.

Reason (R ) : The conditions for film to appear bright of dark in the reflected light are just revese to those in the transmitted light

A. (a) If both assertion and reason are true and reason is the correct explanation of assertion.
B. (b) If both assertion and reason are true but reason is not the correct explanation of assertion.
C. (c) If assertion is true but reason is false.
D. (d) If assertion and reason both are false.

Answer 1

The film which appears bright in a reflected system will appear dark in a transmitted system and vice-versa. The conditions for a film to appear bright or dark in reflected light are just reverse to those in transmitted light.

Step-by-step explanation:

Assertion (A) : The film which appears bright in a reflected system will appear dark in a transmitted system and vice-versa.

Reason (R): The conditions for a film to appear bright or dark in reflected light are just reverse to those in transmitted light.

The given assertion is true. When light strikes a thin film, part of the light is reflected from the top surface and part is refracted at the top surface. The refracted ray is then partially reflected at the bottom surface and emerges as a transmitted ray. These rays interfere with each other, creating an interference pattern. The specific conditions for the interference pattern to be bright or dark depend on the thickness of the film and the indices of refraction of the media involved.

Therefore, the given reason is the correct explanation for the assertion. The correct option is (a) If both assertion and reason are true and the reason is the correct explanation of the assertion.