A ray of light is incident upon an air/water interface ( it passes from air into water) at an angle of `45^(@)` . Which of the following quantities change as the light enters the water?
(I) wavelength `" "` (II) frequency `" "` (III) speed of propagation (IV) direction of propagation

Options

A. (a)I , III only
B. (b)III, IV only
C. (c) I , II ,IV only
D. (d)I , III , IV only

Answer

D

Explanation

As Speed of light in vaccum/air
`mu` = Speed of light if medium
`mu = (c)/(v) implies ` velocity is different in different medium From v= n`lambda`
But frequency is the fundamental property . It never change by changing the medium hence `lambda` is also changed as v is change.