Question

A light ray travels in two media A and B will speeds $2\times {10}^{8}m/s$ and $2.4\times {10}^{8}m/s$. The critical angle between them is

• A. $si{n}^{-1}\left(\frac{8}{9}\right)$
• B. $si{n}^{-1}\left(\frac{5}{6}\right)$
• C. $ta{n}^{-1}\left(\frac{5}{6}\right)$
• D. $co{s}^{-1}\left(\frac{8}{9}\right)$

Answer 1

The correct option is B $si{n}^{-1}\left(\frac{5}{6}\right)$

$\mu =\frac{1}{sinc}=\frac{C_{rarer}}{C_{denser}}=\frac{2.4\times {10}^3}{2\times {10}^3}\frac{1}{sinc}=\frac{6}{5};sinc=\frac{5}{6}C=si{n}^{-1}\left[\frac{5}{6}\right]$