Question

Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Refractive index of glass is more than air.
Reason (R): Optical density of a medium is directly related to its mass density.
In the light of the above statements, choose the correct answer from the options given below.

• A. (A) is false but (R) is true
• B. (A) is true but (R) is false
• C. Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
• D. Both (A) and (R) are true and (R) is the correct explanation of (A)

Hint:

When dealing with assertion and reason questions, make sure to verify the truth of each statement and whether the reason correctly explains the assertion.

Answer 1

The Correct Option is B

- Assertion (A): A material's refractive index is defined as the quotient of the speed of light in a vacuum divided by the speed of light within that material. Given that light travels at a lower velocity in glass than in air, the refractive index of glass is demonstrably greater than that of air. Consequently, assertion (A) is accurate.
- Reason (R): A medium's optical density does not correlate directly with its mass density. The refractive index, which dictates optical density, is dependent on the speed of light in the material. In contrast, mass density pertains to the mass per unit volume of the material. Therefore, reason (R) is incorrect.As assertion (A) is true and reason (R) is false, the correct selection is (2) "Assertion (A) is true but (R) is false."