Question

A beam of light propagating in medium $A$ with index of refraction $\mu_{A}$ passes across an interface into medium $B$ with index of refraction $\mu_{B}$. The angle of incidence is greater than the angle of refraction, $v_{A}$ and $v_{B}$ denote the speeds of light in $A$ and $B$ respectively. Then which of the following is true?

• A. $v_{A} > v_{B}$ and $\mu_{A} > \mu_{B}$
• B. $v_{A} > v_{B}$ and $\mu_{A} < \mu_{B}$
• C. $v_{A} < v_{B}$ and $\mu_{A} > \mu_{B}$
• D. $v_{A} < v_{B}$ and $\mu_{A} < \mu_{B}$

Answer 1

Answer: (B)

Given that $i>r$.
$\Rightarrow \mu_{B} > \mu_{A}$
$\Rightarrow \quad \frac{v}{v_{B}} >\frac{v}{v_{A}}$
or $v_{B} < v_{A}$