"The refracting angle of a prism is A and refractive index of the material of the prism is cot (A/2). Then the angle of minimum deviation will be -"

Question

Accepted Answer

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$$\mu = {{\sin \left( {{{{\delta _m} + A} \over 2}} \right)} \over {\sin (A/2)}} = \cot A/2$$

$\Rightarrow \cos A/2 = \sin \left( {{{{\delta _m} + A} \over 2}} \right)$

$\Rightarrow {\pi \over 2} - {A \over 2} = {{{\delta _m} + A} \over 2}$

$\Rightarrow \pi - 2A = {\delta _m}$

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The refracting angle of a prism is A and refractive index of the material of the prism is cot (A/2). Then the angle of minimum deviation will be -