The graph between angle of deviation `(delta)` and angle of incidence (i) for a triangular prism is represented by

Options

A.
B.
C.
D.

Answer

C

Explanation

We know that the angle of deviation depends upon the angle of incidence. If we determine experimentally, the angles of deviation comparing to different angles of incidence and then plot I (on - x-axis) and `delta` (on y-axis) we get a curve as shown in the figure.

Clearly if angle of incidence is gradually increased from a small value the angle of deviation first decreases, becomes minimum for a particular angle of incidence and then begains to increase.