What is the value of the refractive index fora 90^@-45^@-45^@ prism which is used to deviate a beam through 90^@ by total internal reflection?

What is the value of the refractive index fora 90^@-45^@-45^@ prism wh

1.	What is the value of the refractive index fora 90^@-45^@-45^@ prism which is used to deviate a beam through 90^@ by total internal reflection?
Answer» Solution :At face AB the ray of light suffers no deviation if the INCIDENT normally. At face AC, the light ray UNDERGOES TIR, so angle of incidence at the face AC is greater than critical angle `45^@ gt C, sin 45^@ gt sin C, 1/SQRT2 gt 1/mu, mu gt sqrt2`