$A$ clock hung on a wall has marks instead of numbers on its dial. On the opposite wall there is a mirror,and the image of the clock in the mirror,if read,indicates the time as $8:20$. What is the actual time in the clock?

An object shaped as $L$ is placed between two parallel plane mirrors as shown. In the first seven closest images,how many laterally inverted images are formed?

$A$ light bulb is placed between two plane mirrors inclined at an angle of $60^{\circ}$. The number of images formed is:

$A$ point source of light,$S$,is placed at a distance $L$ in front of the centre of a plane mirror of width $d$ which is hanging vertically on a wall. $A$ man walks in front of the mirror along a line parallel to the mirror,at a distance $2L$ as shown below. The distance over which the man can see the image of the light source in the mirror is:

$A$ two-eyed man is looking at the junction of two mutually perpendicular mirrors from a far-off distance. Assume no reflection occurs from the edge. If both eyes are open,then:

$A$ ray is reflected in turn by three plane mirrors mutually at right angles to each other. The angle between the incident and the reflected rays is......$^o$