Question

A prism has a refracting angle of 60°. When placed in the position of minimum deviation, it produces a deviation of 30°. The angle of incidence is

• A. 30°
• B. 45°
• C. 60°
• D. 15°

Hint:

At the position of minimum deviation, the angle of incidence equals the angle of emergence in a prism.

Answer 1

The Correct Option is B

Step 1: Use the formula for the angle of deviation.
The angle of incidence at minimum deviation is given by: \[ i = \frac{A + D_{\text{min}}}{2} \] where \( A = 60^\circ \) is the refracting angle and \( D_{\text{min}} = 30^\circ \) is the minimum deviation.
Step 2: Calculate the angle of incidence.
Thus, the angle of incidence is: \[ i = \frac{60 + 30}{2} = 45^\circ \]
Final Answer: \[ \boxed{45^\circ} \]