Question

Assertion: Light travels faster in a rarer medium than in a denser medium.

Reason: Refractive index of a medium is inversely proportional to the velocity of light in the medium.

Options

• If both Assertion and Reason are true and the Reason is correct explanation of the Assertion.

• If both Assertion and Reason are true, but Reason is not correct explanation of the Assertion.

• If Assertion is true, but the Reason is false.

• If Assertion is false, but the Reason is true.

Answer 1

If both Assertion and Reason are true and the Reason is correct explanation of the Assertion.

Explanation: 

Since $$\mu = \frac{c}{v}$$, refractive index is inversely proportional to the speed of light in the medium ($$v \propto \frac{1}{\mu}$$). A rarer medium has a smaller refractive index, which directly explains why light travels faster in it.