Question

In a thin prism of glass ( ${}^a{\mu }_g$ = 1.5 ), the relation between the angle of minimum deviations ${\delta }_m$ and angle of refraction r is :

• A. ${\delta }_m=r$
• B. ${\delta }_m=\frac{r}{2}$
• C. ${\delta }_m=2r$
• D. ${\delta }_m=\frac{r}{4}$

Answer 1

Answer: (A)

${\delta }_m=r$

For minimum deviation
$r+r^1=A$ and $r=r^1$
so, $r=A/2$ and ${\delta }_m=(\mu -1)A$

${\delta }_m=(1.5-1)A$
$=0.5A$
$=\frac{A}{2}$ $=r$
So, ${\delta }_m=r$