JAMB Physics 2019 Objective — Question 3

Question 3 of 40 from the Joint Admissions and Matriculation Board (JAMB) Physics 2019 Objective paper, with the correct answer and a full explanation.

Calculate the angle of minimum deviation when light is refracted through an equilateral triangular prism of refractive index 1.5

• A. 40°
• B. 37°
• C. 40.2°
• D. 37.2°Correct

Explanation

Angle of prism A=60°. n=sin[(A+Dm)/2]/sin(A/2) ⇒ 1.5=sin[(60+Dm)/2]/sin30° ⇒ sin[(60+Dm)/2]=0.75 ⇒ (60+Dm)/2=48.59° ⇒ Dm=(2×48.59)−60≈ 37.2°.

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