Question

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

Hint:

Minimum deviation equal to prism angle gives a useful refractive index range.

Answer 1

The Correct Option is A

Step 1: Condition: deltamin=A
Step 2: Prism formula: μ=fracsin(fracA+deltamin2)sin((A)/(2)) ⟹ μ=(sin A)/(sin(A/2))=2cos(A)/(2)
Step 3: Hence: 1<μ<√(2)