Optics 4 Question 8

8. Two beams of red and violet colours are made to pass separately through a prism (angle of the prism is $60^{\circ}$ ). In the position of minimum deviation, the angle of refraction will be

(a) $30^{\circ}$ for both the colours

(b) greater for the violet colour

(c) greater for the red colour

(d) equal but not $30^{\circ}$ for both the colours

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Answer:

Correct Answer: 8. (a)

Solution:

  1. At minimum deviation $\left(\delta=\delta _m\right)$ :

$$ r _1=r _2=\frac{A}{2}=\frac{60^{\circ}}{2}=30^{\circ} \quad \text { (For both colours) } $$



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