Question

On a right angled prism, the rays A, B and C are incident, as shown in the figure. Before emerging from the prism, which ray or rays will experience total internal reflection ?

• A. A
• B. B
• C. C
• D. none of these

Answer 1

The correct option is B B

$\begin{array}{c}\text{from the tig. we see that the}\\ \text{angle of inodence of ray}B\text{is}\\ \text{equal to zero.}\\ \text{Let us redraw the diagram for}\\ \text{ray}B\text{.}\end{array}$

$\begin{array}{c}\text{As ray is}{1}^{1/2}\text{to surface}pR\text{it goes undented,}9n\\ \text{surfare}pQ\text{it makes}{45}^{\circ }\text{with respect to normal of}PQ\text{.}\\ \text{Now, it reflect to surface}QR\text{, esimilarly, it will get}\\ \text{totally reflected.}\end{array}$

$\begin{array}{c}\text{Hence, Ray (B) experience total internal reflection}\\ \therefore \text{(B) is correct ophion.}\end{array}$