Calculate the angle of minimum deviation for a ray which is refracted through an equiangular prism of refractive index 1.4
-
A.
600 -
B.
290 -
C.
990 -
D.
900
Correct Answer: Option B
Explanation
From the relation refractive index = Sin ( left(frac{A+Dm}{2}right) )
Where A = refractive angle = 600, Sin( left(frac{A}{2}right) )
( implies 1.4 = frac{text{Sin}left(frac{60^0 + Dm}{2}right)}{text{Sin}left(frac{60}{2}right)} \
= frac{text{Sin}left(frac{60 + Dm}{2}right)}{text{Sin}30^0} \
= frac{text{Sin}left(frac{60 + Dm}{2}right)}{0.5}\
text{Therefore} 1.4 times 0.5 = text{Sin}left(frac{60 + Dm}{2}right) \
text{Therefore} left(frac{60 + D_m}{2}right)= text{Sin}^{-1} 0.7000 \
= 44^0 12^1 \
60^0 + D_m = 88^0 24^1 \
D_m = 88^0 24^1 – 60^0 \
= 28^0 24 \
29^0 )