Question

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

• A.
• B.
• C.
• D.

Answer 1

Answer: (C)

We know that the angle of
deviation depends upon the
angle of incidence. If we
determine experimentally, the
angles of deviation
corresponding to different angles
of incidence and then plot i
(on-x-axis) and $\delta$ (on-y-axis), we
get a curve as shown in 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 begins
to increase.