$A$ point source of light $S$ is placed in front of two large mirrors as shown. Which of the following observers will see only one image of $S$?

$A$ 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.

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......$m$.

Two mirrors,labeled $LM$ for left mirror and $RM$ for right mirror in the adjacent figure,are parallel to each other and $3.0 \, m$ apart. $A$ person standing $1.0 \, m$ from the right mirror $(RM)$ looks into this mirror and sees a series of images. How far from the person is the second closest image seen in the right mirror $(RM)$ (in $, m$)?

$A$ ray of light travelling in the direction $\frac{1}{2}(\hat{i}+\sqrt{3} \hat{j})$ is incident on a plane mirror. After reflection,it travels along the direction $\frac{1}{2}(\hat{i}-\sqrt{3} \hat{j})$. The angle of incidence is: (in $^{\circ}$)

$A$ boy of height $1.5\, m$ with his eye level at $1.4\, m$ stands before a plane mirror of length $0.75\, m$ fixed on the wall. The height of the lower edge of the mirror above the floor is $0.8\, m$. Then: