Question

A ray incident at an angle of incidence I on one surface of a prism of small angle A and emerges normally from opposite surface. If the refractive index of the material opposite surface. If the refractive index of the material of prism is$\mu$, the angle of incidence I is nearly equal to:

• A. $\frac { \mathrm { A } } { \mu }$
• B.
• C. $\mu \mathrm { A }$
• D. $\frac { \mu \mathrm { A } } { 2 }$

Answer 1

Answer: (C)

$\mu \mathrm { A }$

Answer 2

: As refracted ray emerges normally from opposite surface,

As $\mathrm { A } = \mathrm { r } _ { 1 } + \mathrm { r } _ { 2 } \quad \therefore \mathrm { r } _ { 1 } = \mathrm { A }$

Now,