Question

Light travels a distance x in time t1 in air and 10x in time t2 in another denser medium. What is the critical angle for this medium?

• A. sin-1($\frac{10t_1}{t_2}$)
• B. sin-1($\frac{t_2}{t_1}$)
• C. sin-1(1$\frac{10t_2}{t_1}$)
• D. sin-1($\frac{t_1}{10t_2}$)

Answer 1

Answer: (A)

sin-1($\frac{10t_1}{t_2}$)

Answer 2

The correct option is (B): $sin^{-1}\frac{10t_1}{t_2}$

speed of light in air V1=$\frac{x}{t_1}$

Speed of light in a medium V2=$\frac{10x}{t_2}$

$sin\theta_c=\frac{V_2}{V_1}=\frac{10x}{t_2}\frac{t_1}{x}$

$\theta_c=sin^{-1}(\frac{10t_1}{t_2})$