Question

For an equilateral prism if :
$\angle i=angleofIncidence$
$\angle e=angleofEmergence$
$\angle P=angleofPrism$
$\angle D=angleofDeviation$
then which one relation is correct :

• A. $\angle i+\angle e$ = $\frac{\angle P+\angle D}{2}$
• B. $\angle i+\angle D=\angle P+\angle e$
• C. $\angle i+\angle e=\angle P+\angle D$
• D. $Noneofthese$

Answer 1

Answer: (C)

$\angle i+\angle e=\angle P+\angle D$

$\begin{array}{c}\text{we know,}\\ i+e=A+\delta \\ i\to \text{angle of incidence}\\ e\to \text{angle of emergence}\\ A\to \text{angle of prism}\\ \delta \to \text{angle of deviation}\\ \Rightarrow \angle i+\angle e=\angle P+\angle D\end{array}$