When a ray is refracted from one medium into another, the wavelegths changes from `6000Å` to `4000Å`. The critical angle for a ray from the second medium will be

Options

A. `cos^(-1)((2)/(3))`
B. `sin^(-1)((2)/(sqrt(3)))`
C. `sin^(-1)((2)/(3))`
D. `cos^(-1)((2)/(sqrt(3)))`

Explanation

As `._(1)mu_(2)=(1)/(sinC)`
`implies (mu_(2))/(mu_(1))=(lambda_(1))/(lambda_(2))=(1)/(sinC)`
`implies (6000)/(4000)=(1)/(sinC)`
implies Critical angle, `C=sin^(-1)((2)/(3))`