Question

Two plane mirrors $M _{1}$ and $M _{2}$ are at right angle to each other shown. A point source '$P$' is placed at '$a$' and '$2a$' meter away from $M _{1}$ and $M _{2}$ respectively. The shortest distance between the images thus formed is : (Take $\sqrt{5}=2.3$ )

• A. $3\, a$
• B. $4.6\, a$
• C. $2.3\, a$
• D. $2 \sqrt{10} \,a$

Answer 1

Answer: (B)

Shortest distance is $2 a$ between $I _{1} \,\&\, I _{3}$
But answer given is for $I _{1} \,\&\, I _{2}$
$\sqrt{(4 a)^{2}+(2 a)^{2}}$
$a \sqrt{20}$
$4.47\,a$