In your laboratory you trace the path of light rays  through a glass slab for different values of angle  of incidence (∠i) and in each case measure the  values of the corresponding angle of refraction  (∠r) and angle of emergence (∠e).  On the basis of your observation your correct  conclusion is:  

(a) ∠i is more than ∠r, but nearly equal to ∠e  

(b) ∠i is less than ∠r, but nearly equal to ∠e  

(c) ∠i is more than ∠e, but nearly equal to ∠r  

(d) ∠i is less than ∠e, but nearly equal to ∠r  

 

Answer

refraction-through-a-rectangular-glass-slab---teachoo.jpg

 

  • When light enters from air to glass, it bends towards the normal
  • Hence, angle of refraction is less than angle of incidence
  • When light leaves the surface of glass to air
  • It bends away from the normal
  • This, angle of emergence is almost equal to angle of incidence

 

So, the correct answer is (a) - ∠i is more than ∠r, but nearly equal to ∠e 

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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