Question

Figure shows the graph of angle of deviation $\delta$ versus angle of incidence $i$ for a light ray striking a prism. The prism angle is

• A. ${30}^o$
• B. ${45}^o$
• C. ${60}^o$
• D. ${75}^o$

Answer 1

The correct option is B ${45}^o$

By comparing graph with standard plot, we get $\delta =30°,i_1=15°,i_2=60°$

as $\delta =i_1+i_2-A\therefore A=i_1+i_2-\delta =15°+60°-30°=45°$