Study the following figure in which a student  has marked the angle of incidence (∠i), angle of  refraction (∠r), angle of emergence (∠e), angle of  prism (∠A) and the angle of deviation (∠D). The  correctly marked angles are: 

q18.jpg

(a) ∠A and ∠i 

(b) ∠A, ∠i and ∠r  

(c) ∠A, ∠i, ∠e and ∠D 

(d) ∠A, ∠i, ∠r and ∠D  

 

Answer

refraction-of-light-through-a-glass-prism---teachoo.jpg

  • Angle of incidence is the angle between incident ray and normal.
    So, here angle of incidence is angle i. It is marked correct

  • Angle of refraction is the angle between refracted ray and normal.
    So, here angle of incidence is angle r. It is marked incorrectly

 

  • Angle of emergence is the angle between emergent ray and normal.
    So, here angle of emergence is angle D, not angle e. So, it is marked incorrectly

 

  • Angle of deviation is the angle between emergent ray and incident ray (when produced backwards).
    So, here angle of emergence is angle e, not angle D. So, it is marked incorrectly

 

  • Angle of prism is the vertex angle of the prism.
    Here, it is angle A. It is marked correct

Study the following figure in which a student  has marked the angle of incidence.jpg

So, the correct answer is (a) - ∠A and ∠i

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Maninder Singh

CA Maninder Singh is a Chartered Accountant for the past 14 years and a teacher from the past 18 years. He teaches Science, Economics, Accounting and English at Teachoo