Question

A prism $(\mu =1.5)$ has the refracting angle of ${30}^{\circ }$. The deviation of a monochromatic ray incident normally on its one surface will be $(sin{48}^{\circ }{36}^{\prime }=0.75)$

• A. ${18}^{\circ }{36}^{\prime }$
• B. ${20}^{\circ }{30}^{\prime }$
• C. ${18}^{\circ }$
• D. ${22}^{\circ }{1}^{\prime }$

Answer 1

The correct option is A ${18}^{\circ }{36}^{\prime }$

By using $\mu =\frac{sini}{sinA}\Rightarrow 1.5=\frac{sini}{sin30}\Rightarrow sini=0.75\Rightarrow i={48}^{\circ }{36}^{\prime }$
Also from $\delta =i-A\Rightarrow \delta ={48}^{\circ }{36}^{\prime }-{30}^{\circ }={18}^{\circ }{36}^{\prime }$