Question

The angle of deviation through a prism is minimum when


(A) Incident ray and emergent ray are symmetric with respect to the prism.
(B) The refracted ray inside the prism becomes parallel to its base.
(C) Angle of incidence is equal to angle of emergence.
(D) When the angle of emergence is double the angle of incidence.
Choose the correct answer from the options given below:

• A. Only statement (D) is true
• B. Statement (A), (B) and (C) are true
• C. Statement (B) and (C) are true
• D. Only statement (A) and (B) are true

Answer 1

The correct option is B Statement (A), (B) and (C) are true


Deviation is minimum in prism when,
(i) $i=e$
(ii) $r_1=r_2$
(iii) ray inside the prism is parallel to the base of the prism.

The above conditions will all be satisfied i.e statements (A), (B) and (C) are true.

Hence, option (b) is correct.