JEE MAIN - Physics (2020 - 5th September Evening Slot - No. 21)

A prism of angle A = 1o has a refractive index $$\mu $$ = 1.5. A good estimate for the minimum angle of deviation (in degrees) is close to $${N \over {10}}$$.
Value of N is ____.
Answer
5

Explanation

Deviation for small-angled prism is given by

$$\delta$$ = ($$\mu$$ $$-$$ 1) A

Given, A = 1$$^\circ$$, $$\mu$$ = 1.5

Substituting these values in above equation, we get

$$\delta$$ = (1.5 $$-$$ 1)1 $$\delta$$ = 0.5

According to question, $$\delta = {N \over {10}}$$

$$ \Rightarrow 0.5 = {N \over {10}} = N = 5$$

Hence, the value of N is 5.

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