Question

After tracing the path of rays of light through a glass slab for three different angles of incidence, a student measured the corresponding values angle of refraction r and angle of emergence e and recorded them in the table given below: 

S. No.	∠i	∠i	∠e
I	30°	20°	31°
II	40°	25°	40°
III	50°	31°	49°

The correct observations are:

(A) I and II

(B) II and III

(C) I and III

(D) I, II and III

Answer 1

(D)

For light rays passing through a glass slab, the following conditions should hold true:

(1) ∠i ≈ ∠e and ∠r < ∠i

(2) Also, with the increase in incident angle, the refracted angle also increases.

Both of these conditions are satisfied in all the three observations.