Question

at which condition there will be no deviation of light rays entering a medium from a different medium

Answer 1

There are mainly two conditions on which the light rays entering a media from a different medium will not undergo any deviation:

1. When the refractive indices of the two media are same, then light ray passes without any deviation or refraction.

Proof:

Let incidence angle be i and refracted angle be r:

$\therefore \: \mu1 \sin(i) = \mu2 \sin(r)$

$= > \: \mu \sin(i) = \mu\sin(r)$

$= > \: \sin(i) = \sin(r)$

$= > \: \angle i = \angle r$

So, deviation is zero.

2. If the ray is incident perpendicular to the interface (at 0° to normal) , then the ray passes undeviated.

Proof:

$\therefore \: \mu1 \sin(i) = \mu2 \sin(r)$

$= > \: \mu1 \sin(0 \degree) = \mu\sin(r)$

$= > \: \mu1 \times 0 = \mu\sin(r)$

$= > \: \mu\sin(r) = 0$

$= > \: \sin(r) = 0$

$= > \: \angle r = 0$

So, the ray passes undeviated.

[Hence Proved]

Answer 2

Condition when light enters from different medium will not deviate:

• There is merely one condition when a ray of light incoming a medium from a diverse medium will not deviate

• when the ray is incident on the interface unravelling the two mediums usually to the interface i.e. when the angle of incidence is 0.

•  In this case there is no deviation from the unique path. If angle of incidence is 0, then the angle of refraction is also 0.

Hope it helped..