Question

Rahim recorded the following sets of observations while tracing the path of a ray of light passing through a rectangular glass slab for different angles of incidence.
S. No.
Angle of incidence
Angle of refraction
Angle of emergence
I
45°
41°
45°
II
40°
38°
38°
III
45°
41°
40°
IV
41°
45°
41°
The correct observation is recorded at serial number: (1) I
(2) II (3) III (4) IV

Answer 1

(1) I -- 45°; 41°; 45°

Explanation:

When light is refracted through a glass slab, angle of incidence = angle of emergence. So ∠i = ∠e. The light passes from rarer medium (air) to the denser medium (glass). So the light ray will bend towards the normal. Hence angle of refraction will be less than the angle of incidence or angle of emergence.

So Option 1 is correct.  

Angle of incidence = 45°

Angle of refraction = 41°

Angle of emergence = 45°