$A$ tall man of height $6$ feet wants to see his full image. The required minimum length of the mirror will be ......... feet.

Two plane mirrors are inclined at an angle of $72^{\circ}$. The number of images of a point object placed between them will be

$A$ ray of light is incident on a plane mirror at an angle of $60^{\circ}$. The angle of deviation produced by the mirror is (in $^{\circ}$)

Digital movie projectors work on the principle of

$A$ man runs towards a plane mirror at a speed of $15 \, m/s$. The speed of the image relative to the mirror is ...... $m/s$.

$A$ flat mirror $M$ is arranged parallel to a wall $W$ at a distance $l$ from it. The light produced by a point source $S$ kept on the wall is reflected by the mirror and produces a light spot on the wall. The mirror moves with velocity $v$ towards the wall.