Light enters from air into a medium of R.I. 1.5. What is the percentage change in its wavelength?

Options

A. `66.66%`
B. `50%`
C. `33.33%`
D. `25%`

Answer

C

Explanation

`mu_(m) = 1.5, lambda_(a) - lambda_(m) = ?`
`mu_(m) = (lambda_(a))/(lambda_(m)) :. lambda_(m) = (lambda_(a))/(lambda_(m)) = (lambda_(a))/(1.5)`
`lambda_(a) = lambda_(m) = lambda_(a) - (lambda_(a))/(1.5) = (1.5 lambda_(a) - lambda_(a))/(1.5)`
`= (0.5)/(1.5) lambda_(a) = (lambda_(a))/(3)`
Now percentage change in wavelength
`= ((lambda_(a) - lambda_(m))/(lambda_(a)))100`
`= (lambda_(a))/(3 xx lambda_(a)) xx 100`
`= 33.33%`