Power of a plane mirror is . . . . . .

$A$ light ray is incident on a plane mirror at an angle of incidence of $30^\circ$. The deviation produced by the mirror is ........$^\circ$.

$A$ small object of size $10\, cm$ is placed in front of a plane mirror. $A$ person stands $30\, cm$ behind the object and views the image of the object. At what distance (in $cm$) from the person's eyes must the image be focused?

$A$ 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 $m/s$)

$A$ 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 $,s$)

The figure shows a cubical room $ABCD$ with the wall $CD$ as a plane mirror. Each side of the room is $3\,m$. $A$ camera is placed at the midpoint of the wall $AB$. At what distance should the camera be focused to photograph an object placed at $A$?