Question

To get three images of a single object, one should have two plane mirrors at an angle of

• A. $60^{\circ }$
• B. $90^{\circ }$
• C. $120^{\circ }$
• D. $30^{\circ }$

Answer 1

Answer: (B)

$n=\frac{360^o}{{\theta }^o}-1$
$\therefore$ $3=\frac{360^o}{{\theta }^o}-1\Rightarrow 4{\theta }^o=360^o\Rightarrow {\theta }^o=90^o$ .