Question

The velocity of light in a piece of matter(air) is v. The thickness of the piece is t and its refractive index is $\mu$. The distance traveled by light in air in time t/v is :

• A. $\mu t$
• B. $\mu t^2$
• C. $\mu t^3$
• D. $\mu t^4$

Answer 1

Answer: (A)

$\mu t$

Velocity of light in any material is $v=\frac{c}{\mu }$
Therefore velocity of light in air $c=\mu v$
Therefore, distance traveled by it in time $\frac{t}{v}$ is:
$\mu v\times \frac{t}{v}=\mu t$