Two plane mirrors are at $45^{\circ}$ to each other. If an object is placed between them,then the number of images will be

$A$ 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:

It is desired to photograph the image of an object placed at a distance of $3\;m$ from a plane mirror. The camera,which is at a distance of $4.5\;m$ from the mirror,should be focused for a distance of......$m$.

$A$ light ray makes an angle of $10^{\circ}$ with the horizontal. It is incident on a plane mirror which makes an angle $\theta$ with the horizontal. If the reflected ray travels in the vertically upward direction,then $\theta = .....^{\circ}$

$A$ ray of light making an angle $10^o$ with the horizontal is incident on a plane mirror making an angle $\theta$ with the horizontal. What should be the value of $\theta$ so that the reflected ray goes vertically upwards?

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