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

The rear window of a car has a size of $120 \, cm \times 45 \, cm$. The driver sits at a distance $L = 2 \, m$ from the rear window. What should be the minimum size of a flat mirror,hanging at a distance of $0.5 \, m$ in front of the driver,so that he has the best view of the road situation behind the car?

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

$A$ ray gets successively reflected from two mirrors inclined at an angle of $40^o$. If the angle of incidence on the first mirror is $30^o$,then the net deviation of this ray after two reflections is: (in $^o$)

For a plane mirror,the focal length is . . . . . . $m$.

$A$ girl of height $150 \,cm$ with her eye level at $140 \,cm$ stands in front of a plane mirror of height $75 \,cm$ fixed to a wall. The lower edge of the mirror is at a height of $85 \,cm$ above her feet level. The height of her image the girl can see in the mirror is (in $cm$)