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A ray \mathrm{PQ} incident on the refracting face \mathrm{BA} is refracted in the prism \mathrm{BAC} as shown in the figure and emerges from the other refracting face \mathrm{AC} as \mathrm{RS} such that \mathrm{AQ = AR}. If the angle of prism \mathrm{A = 60^{\circ}} and refractive index of the material of prism is \mathrm{\sqrt{3}}, then the angle of deviation of the ray is:

Option: 1

60^{\circ}


Option: 2

45^{\circ}


Option: 3

30^{\circ}


Option: 4

None of these 


Answers (1)

best_answer

For a given prism, the angle of deviation depends upon the angle of incidence of the light rays falling on the prism. Taking triangle \mathrm{FQR}, we have
\mathrm{\begin{aligned} & \delta=\angle \mathrm{FQR}+\angle \mathrm{FRQ} \\ & \therefore \quad \delta=30^{\circ}+30^{\circ}=60^{\circ} \end{aligned}}
Hence, angle of deviation of the ray is \mathrm{60^{\circ}}.

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seema garhwal

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