Refraction by Prism

Practice Questions:

Question 1: easy

The angle of minimum deviation for a prism is 40° and the angle of the prism is 60°. The angle of incidence in the position will be

1. 30°

2. 60°

3. 50°

4. 100°

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Question 2: easy

Refractive index of a prism is \(cosec(A/2)\). Then minimum angle of deviation is :

1. \(180^0 –A\)

2. \(180^0–2A\)

3. \(90^0–A\)

4. \(A/2\)

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Using the prism formula: \(mu = \frac{sin((A+\delta_m)/2)}{sin(A/2)}\). Substituting \(mu = cosec(A/2) =\frac{1}{sin(A/2)}\), we get \(sin((A+\delta_m)/2) = 1 ⇒ (A+\delta_m)/2 = 90^0 ⇒ \delta_m = 180^0 - A\).

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