Question

The correct graph between angle of deviation $\left(\delta \right)$ and angle of the incident $\left(i\right)$ for a triangular prism is best represented by

• A.
• B.
• C.
• D.

Answer 1

Answer: (A)

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 the figure.


Clearly, if the 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.