Question

Let two mirrors A and B be separated by a distance of $10m$. Let object O be placed at midpoint of the mirrors. Let $I_1$ be the first image in mirror A and $I_2$ be the second image in mirror B. What is the distance between $I_1$ and $I_2$?

• A. $10m$
• B. $20m$
• C. $30m$
• D. $40m$

Answer 1

Answer: (C)

$30m$

Let O be the origin and position of mirrors be $A:5m$ and $B:-5m$

Then, $I_{1}O=2AO=10m$

Hence, position of $I_1=10m$

This serves as object for second image.

Then, $I_{2}B=I_{1}B=15m$

$I_{2}O=I_{2}B+OB=20m$

Hence, position of $I_2=-20m$

$I_1{I}_2=10-(-20)=30m$