Question

The speed of light in two media I and II are $2.2\times {10}^{8}m/s$ and $2.4\times {10}^{8}m/s$ respectively. The critical angle for light refracting from I to II medium will be

• A. ${\sin }^{-1}\left(\frac{12}{11}\right)$
• B. ${\sin }^{-1}\left(\frac{11}{12}\right)$
• C. ${\sin }^{-1}\left(\frac{12}{24}\right)$
• D. ${\sin }^{-1}\left(\frac{12}{21}\right)$

Answer 1

Answer: (B)

${\mu }_r=\frac{2.4}{2.2}$

critical angle is $si{n}^{-1}\frac{1}{{\mu }_r}=si{n}^{-1}\frac{11}{12}$