$A$ man runs towards a plane mirror at a speed of $15 \ m/s$. What is the speed of his image relative to the mirror? (in $m/s$)

$A$ thick plane mirror shows a number of images of the filament of an electric bulb. Of these,the brightest image is the

$A$ 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.

When a beam of light is incident on a plane mirror,it is found that a real image is formed. The incident beam must be

$A$ ray reflected successively from two plane mirrors inclined at a certain angle undergoes a deviation of $300^o$. The number of observable images is:

$A$ point source of light $S$ is placed at a distance $10\,cm$ in front of the centre of a mirror of width $20\,cm$ suspended vertically on a wall. $A$ man walks with a speed $10\,cm/s$ in front of the mirror along a line parallel to the mirror at a distance $20\,cm$ from it as shown in the figure. Find the maximum time during which he can see the image of the source $S$ in the mirror. (in $,s$)