To obtain $3$ images using two plane mirrors, they should be placed at an angle of ....... $^o$.

$A$ 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:

If the time shown in a mirror is $3:25$,what is the actual time?

Ray $1$ is parallel to the horizontal mirror. Ray $2$ is parallel to the other mirror. Then the angle between the two mirrors is .......... $^o$.

Digital movie projectors work on the principle of

An object is placed between two plane mirrors inclined at some angle to each other. If the number of images formed is $7$, then the angle of inclination is: (in $^{\circ}$)