Based on the condition of no emergence from face AC
In the shown figure,
`A=110^@,B=20^@,C=50^@,i_1=45^@` and `mu=sqrt2`
Find the total deviation by prism.

Answer

B

Explanation

`theta_C=sin^-1(1/mu)=sin^-1(1/sqrt2)=45^@`
Here, `Agt2 theta_C`
Therefore, TIR will take place at AC and the ray of light
emerges from the prism as shown in figure.
Applying, `mu=sini/sinr` at M and Q, we can find the respective
angles as shown in figure.
Now, deviation at M is clockwise, deviation at N is clockwise but deviation at Q is
anti-clockwise.
`:. delta_("Total")=delta_M+delta_N-delta_Q`
`=(45^@-30^@)+(180^@-2xx80^@)-(45^@-30^@)`
`=20^@`