Q. For the angle of minimum deviation of a prism to be equal to its refracting angle, the prism must be made of a material whose refractive index :
A) lies between √2 and 1
B) lies between 2 and √2
C) is less than 1
D) is greater than 2
Explanation
[Solution from source] μ = sin((A + δm)/2)/sin(A/2); with δm = A this becomes μ = sin A/sin(A/2) = 2cos(A/2). For a real emergent ray A/2 ranges between 0 and 45°, so μ lies between √2 and 2. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.