question_answer

A vessel consists of two plane mirrors at right angle (as shown in figure). The vessel is filled with water. The total deviation in incident ray  

A)  \[{{0}^{o}}\]              

B)  \[{{90}^{o}}\]

C)  \[{{180}^{o}}\]          

D)  none of these

Correct Answer: C

Solution :

 Key Idea: Phenomenon of reflection is independent of medium. The deviation produced by combination of two plane mirrors is \[\delta =2\pi -2\theta \] \[=2\pi -2\times \frac{\pi }{2}\] \[(\theta ={{90}^{o}})\] \[\Rightarrow \] \[\delta =\pi ={{180}^{o}}\]. Hence, total deviation in incident ray is\[{{180}^{o}}\].