Question

The critical angle for light going from medium X into medium Y is $\theta$. The speed of light in medium X is v, then speed of light in medium Y is

• A. $v(1-cos\theta )$
• B. $v/sin\theta$
• C. $v/cos\theta$
• D. $vcos\theta$

Answer 1

Answer: (B)

$v/sin\theta$

critical angle condition:

${\mu }_X\sin \theta ={\mu }_Y$

Given, speed of light in medium X is v

To find: speed of light in medium Y

$\frac{{\mu }_Y}{{\mu }_X}=\sin \theta$

Also, speed of light in medium $Y$ is $=\frac{v}{{\mu }_{rel}}=v\frac{{\mu }_X}{{\mu }_Y}$

$=\frac{v}{\sin \theta }$