Question

Comprehension Type:
ABC is right angled prism. A ray (1) is incident on the face AB along the normal
Another ray (2) is incident on the face AB such that it emerges normally from the
face AC. then the minimum value of refractive index of the material of the prism for which the
ray (1) under goes total internal reflection on the face AC is
1)1
2)2
3) 5
4) V2
​

Answer 1

Answer:

Option (4) $n=\sqrt{2}$

Explanation:

As shown in figure

The angle of incidence $i=45^\circ$

Angle of refraction $r=90^\circ$

If the refractive index of prism w.r.t. air is n then

From snell's law

$\frac{\text{Refractive Index of air}}{\text{Refractive index of prism}}=\frac{\sin i}{\sin r}$

$\implies\frac{1}{n}=\frac{\sin 45^\circ}{\sin 90^\circ}$

$\implies\frac{1}{n}=\frac{1}{\sqrt{2}}$

$\implies n=\sqrt{2}$

Therefore, Opton (4) is correct.

Hope this helps.

Answer 2

Answer:

2

Explanation:

See the explanation below.