$A$ ray of light is incident normally on a plane mirror. The angle of reflection will be

By what angle should $M_2$ be rotated,so that the light ray after reflection from both mirrors becomes horizontal? (The angle of incidence at mirror $M_1$ is $40^{\circ}$ and the angle between $M_2$ and the horizontal is $25^{\circ}$ as shown in the figure.)

Two plane mirrors $A$ and $B$ are placed parallel to each other as shown in the figure. $A$ light ray is incident on mirror $A$ at an angle of $30^o$. The plane of incidence coincides with the plane of the figure. What is the maximum number of reflections (including the first one) the ray will undergo before emerging?

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

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......$m$.