$A$ plane mirror reflects a pencil of light to form a real image. Then the pencil of light incident on the mirror is

$A$ ray of light is reflected by a plane mirror. $\hat{e}_0$,$\hat{e}$ and $\hat{n}$ be the unit vectors along the incident ray,reflected ray and the normal to the reflecting surface respectively. Which of the following gives an expression for $\hat{e}$?

Assertion : If the angle between the two plane mirrors is $72^o$ and the object is asymmetrically placed between the two mirrors,then $5$ images of the object will be formed.
Reason : For a given system of mirrors,the total number of images formed due to successive reflection is equal to either $\frac{360^o}{\theta}$ or $\frac{360^o}{\theta} - 1$ accordingly as $\frac{360^o}{\theta}$ is odd or even respectively.

$A$ person is in a room whose ceiling and two adjacent walls are mirrors. How many images are formed?

Two plane mirrors are placed parallel to each other at a distance $L$ apart. $A$ point object $O$ is placed between them at a distance $L/3$ from one mirror. Both mirrors form multiple images. The distance between any two images cannot be:

$A$ mirror is placed at a distance of $60 \ m$ from the base of a tower. The angle between the top of the tower and the top of its image is $90^o$. Find the height of the tower in $m$.