Question

If $A$ is the angle of prism, $r$ angle of refraction, then the condition for minimum deviation is

• A. $A = r^2$
• B. $A = 2r$
• C. $A = \frac{r}{2}$
• D. $A = r$

Answer 1

Answer: (B)

$A = 2r$

Answer 2

As $r_1 + r_2=A$
At minimum deviation, $r_1 = r_2 = r$
$\therefore \, 2r = A$