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

Options

A. Lies between `sqrt(2)` and 1
B. Lies between 2 and `sqrt(2)`
C. Is less than I
D. Is greater than 2

Answer

B

Explanation

n `= (sin ( (A + delta_(m))/(2)) )/(sin A//2) = (sin ((A + A)/(2)) )/(sin A//2) = (2 sin A//2 cos A// 2 )/(sin A // 2 )`
n = 2 cos `(A)/(2)`
`(n)_(min) = 2 cos (90)/(2) sqrt(2), " " (n)_(max) = 2 cos 0^(@) = 2. `