Question

Minimum deviation produced by a equilateral prism is 30°. If the velocity of light in vacuum is 3 x 10^8 m/s. Then what will be the velocity of light in glass?
(sin 30= 0. 5, Sin 45= 0. 707, Sin 60 = 0. 866)

please, it is very urgent.. I give away my 20 pts for this. Somebody answer this..

Answer 1

For small angled prism,
    n ( refractive index ) = Sin [(A+D) / 2 ]÷ Sin (A/2)
     A - angle of prism = 60°
    D - minimum deviation = 30°
∴  n = Sin [ (60+30) / 2] ÷ Sin (60/2)
i.e Sin 45 / Sin 30 = 1.414
velocity of light in glass (v) = C /n 
∴ V = (3 × 10^8) ÷ 1.414
      = 2.12 × 10^8 m/s