The index of refraction can be defined as the velocity of light In a vacuum divided by the velocity In the medium `(N=C/S)` If this is the case, another valid expression for Snell's law Is

Options

A. `(Sin theta_i)/(Sin theta_r)=C_r/S_r`
B. `(Sin theta_i)/(Sin theta_r)=C_i/C_r`
C. `S_i/S_r=N_r/N_i`
D. `(Sin theta_i)/(Sin theta_r)=S_i/S_r`

Answer

D

Explanation

If `N=C/S , therefore N_r=C/S_r` and `N_i=C/s_i` substituting in the Snell's law again
`(Sin theta_i)/(Sin theta_r)=(C/S_r)/(C/S_i)` where C=speed of light in vacuum and `S_i` and `S_r` is speed of light in medium
Then `n(Sin theta_1)/(Sin theta_2)=S_i/S_r`