Question

A boy stands straight infront of a mirror at a distance of 30cm away from it. He sees his erect image whose height is $\frac{1}{5}$ of his real height. The mirror he is using is
(a) Plane mirror
(b) Convex mirror
(c) Concave mirror
(d) Plano-convex mirror

Answer 1

Here is your answer

b) <tex><b>Convex mirror </b></tex>

<tex><b><u> REASON </u></b></tex>
We know that the images formed by convex mirrors are
Erect,
Diminished (i.e. smaller than the object)
and, image distance is shorter than the object distance.

As in question
the height of image is 1/5 times that of boy so it is diminished image.

Hence the mirror is
CONVEX MIRROR

HOPE IT IS USEFUL

Answer 2

Answer:

The mirror he is using is Convex mirror.

Explanation:

• A convex mirror can produce an erect, virtual and diminished image.

Given:

Height of image =  $\frac{1}{5} th$ of real height.

$\frac{-\mathrm{v}}{\mathrm{u}}=\mathrm{M} < 1 \\ \mathrm{v} < -\mathrm{u} \\\frac{1}{\mathrm{v}} > -\frac{1}{\mathrm{u}} \\\frac{1}{\mathrm{v}}+\frac{1}{\mathrm{u}}=\frac{1}{\mathrm{f}} \\\frac{1}{\mathrm{f}} > \frac{1}{-\mathrm{u}}+\frac{1}{\mathrm{u}} > 0 \\\\\mathrm{f} > 0 \\ { Convex mirror }\end{aligned}$

. The mirror he is using is Convex mirror.