$A$ ray of light is incident on a plane mirror at an angle of $60^{\circ}$. The angle of deviation produced by the mirror is (in $^{\circ}$)

The figure shows two rays $A$ and $B$ being reflected by a mirror and emerging as $A'$ and $B'$. The mirror

$A$ 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 $\theta = .....^{\circ}$

If $\hat{n}_1, \hat{n}_2$ and $\hat{t}$ represent unit vectors along the incident ray, reflected ray, and normal to the surface respectively, then:

$A$ plane mirror produces a magnification of

$A$ 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 $,s$)