A ray of light is travelling from a denser medium to rarer medium. For these media the critical angle is C. The maximum possible deviation of the ray is ...........

[Hint : The situation at total reflection is shown in the figure.]

Options

A. `pi-2`
B. `pi-2C`
C. 2C
D. `pi/2+C`

Answer

B, C

Explanation

From figure, `delta`=r-i
But if i=C`impliesr=90^@=pi/2`
`therefore delta=pi/2-C`
`therefore2 delta=pi-2C` Where,`2delta` is maximum deviation.

Second Method :
Deviation becomes maximum when ray of light experiences total internal refraction.
From it is clear that maximum deviation
`theta=pi-(C+C)=pi-2C`
[Note : angle of incidence for `theta_i gt C` is taken as `theta_i cong C`.]