What is the velocity of the light in the medium if Sin `theta_i`=0.707 , Sin `theta_r`=0.500 , and the velocity of light in a vacuum is `3.0xx10^8` m/sec ?

Options

A. `2.1xx10^8` m/sec
B. `2.8xx10^8` m/sec
C. `1.4xx10^8` m/sec
D. `4.2xx10^8` m/sec

Answer

A

Explanation

Using `(Sin theta_i)/(Sin theta_r)=S_i/S_r` and knowing that
`S_1=3xx10^8` m/sec
`S_r=S_i((Sin theta_r)/(Sin theta_i))=(3xx10^8)(0.500/0.70)`
`S_r=(3)(7)(10^8)=2.1xx10^8` m/sec