Question

The minimum value of the refractive index for a 90° – 45° – 45° prism which is used to deviate a beam by 90° by the phenomenon of total internal reflection is ____

• A. $\sqrt{2}$
• B. 1
• C. 0
• D. 2

Answer 1

The correct option is A $\sqrt{2}$

As per the formula:

u = 1/ Sin i

For minimum the u > 1/sin i

u > 1/sin 45

u > 1/(1√2)

u >√2