Question

A prism can produce a minimum deviation δ in a light beam. If three such prisms are combined, the minimum deviation that can be produced in this beam is
(a) 0
(b) δ
(c) 2δ
(d) 3δ

Answer 1

Answer:

option b is the correct answer

Answer 2

A prism can produce a minimum deviation δ in a light beam. If three such prisms are combined, the minimum deviation that can be produced in this beam is δ

Explanation:

• Angle of deviation produced by single prism =$\delta$.

• All the prisms have same angel of deviation.

• When two prisms are combined then there would be no deviation at the end.

• So angle of deviation due to 2 prisms is zero.(as the angle of deviations are equal).  

• When third prism is combined the resultant angle of deviation will be same = $\delta$.

• Thus the combination of 3 prisms will give angle of prism $\delta$.