Optical Density and Mass Density – Rankers Physics

Refraction by Plane Surfaces: Practice Problem & Solution

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. Assertion A: The mass density of an optically denser medium is greater than that of an optically rarer medium. Reason R: Optical density is found by the ratio of the speed of light in two media while mass density is mass per unit volume. In the light of the above statements, choose the correct answer from the option given below.
Both A and R are true and R is the correct explanation of A
Both A and R are true but R is not the correct explanation of A
A is true but R is false
A is false but R is true

Solution Explained:

To solve this problem, we apply the core principles of Refraction by Plane Surfaces. Understanding the underlying formula is key to arriving at the correct answer below:

Mass density and optical density are not directly related. For example, oil is optically denser than water but has a lower mass density. Thus, Assertion A is false but Reason R is true.

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