Question

The angle of deviation through a prism is minimum when

1. Incident rays and emergent rays are symmetric to the prism.
2. The refracted ray inside the prism becomes parallel to its base.
3. The angle of incidence is equal to that of the angle of emergence.
4. When the angle of emergence has doubled the angle of incidence.

Choose the correct answer from the options given below:

Options

• Only statement (D) is true.

• Statements (A), (B) and (C) are true.

• Statements (B) and (C) are true.

• Only statement (A) and (B) are true.

Answer 1

Statements (A), (B), and (C) are true.

Explanation:

Condition for the minimum angle of deviation

i = e[angle of incidence = angle of emergence]

r₁ = r₂ [refracted ray is parallel to the base of the prism.]

In relation to the prism, incident, and emerging rays are symmetric. Inside the prism, the refracted light becomes parallel to its base. The angle of emergence and angle of incidence are the same.