Question

A point object is placed in front of a thick plane mirror as shown in figure below. Find the location of final image w.r.t. object.

• A. $15/2cm$
• B. $15cm$
• C. $40/3cm$
• D. $80/3cm$

Answer 1

The correct option is D $80/3cm$

From the mirror, It will appear as if the object has moved towards the glass block by $t(1-\frac{1}{\mu })=5(1-\frac{1}{\frac{3}{2}})=\frac{5}{3}cm$

So the apparent distance from the mirror will be $10+5-\frac{5}{3}=\frac{40}{3}cm$

So image will form $\frac{40}{3}cm$ behind the mirror.

While looking at the image through the glass block from the opposite side of the mirror, it will again shift towards the mirror by $\frac{5}{3}cm$

So the apparent distance will be $\frac{40}{3}-\frac{5}{3}=\frac{35}{3}cm$

So, the distance of the final image with respect to the object is $15+\frac{35}{3}=\frac{80}{3}cm$