Question

Two mirrors are inclined at an angle $\theta$. For an object placed in front of them, 11 images are noticed. Find the angle between the mirrors :

• A. ${30}^{\circ }$
• B. ${32.8}^{\circ }$
• C. ${16.4}^{\circ }$
• D. ${15}^{\circ }$

Answer 1

The correct option is A ${30}^{\circ }$

When two plane mirrors are inclined to each other at an angle $\theta$ ,then number of images ($n$) formed of an object which is kept between them is given by
$n=(\frac{360}{\theta }-1)$

Given $n=11$

$⟹(\frac{360}{\theta }-1)=11$

$⟹\theta ={30}^o$