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
(2008, 3M)
(c) greater for the red colour
(d) equal but not $30^{\circ}$ for both the colours
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Solution:
- At minimum deviation $\left(\delta=\delta _m\right)$ :
$$ r _1=r _2=\frac{A}{2}=\frac{60^{\circ}}{2}=30^{\circ} \quad \text { (For both colours) } $$
