Question

A man of height 1.68 m standing at a distance 3m from a plane mirror. What is the distance between the man and his image?

Answer 1

Dear student,
We know for plane mirror,
the distance of object from mirror = distance of image from mirror.
So, for this question,
it is given that distance of the man and the plane mirror =3 m
then,
distance of his image from plane mirror =3 m
hence,
the distance of man and his image =3 m+3 m =6 m
$$\begin{gathered} [Note \\ frommirrorformula \\ \frac{1}{v}+\frac{1}{u}=\frac{1}{f} \\ andforplanemirrorf=focallength=\infty \\ \Rightarrow \frac{1}{v}+\frac{1}{u}=0 \\ \Rightarrow \frac{1}{v}=-\frac{1}{u} \\ \Rightarrow v=-u \\ where \\ v=imagedis\tan ceandu=objectdis\tan ce \\ thenegativesignonlydepictsthattheimageisformedinsidethemirror.] \end{gathered}$$

Regards,