In vacum, to travel distance d, light takes time t and in medium to travel distance 5d, it takes time T. The critical angle of the medium is

Options

A. `sin^(-1) ((5T)/(t))`
B. `sin^(-1) ((5t)/(3T))`
C. `sin^(-1) ((5t)/(T))`
D. `sin^(-1) ((3t)/(5T))`

Answer

C

Explanation

In vacuum , `c = d//t`
In medium , v `= (5d)/(T)`
As refractive index `, mu = (c)/(v) = (d//t)/(5d//t) = (T)/(5t)`
Also , sin C `= (1)/(mu) therefore C = sin^(-1) [(5t)/(T)]`