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

The following figure shows the multiple reflection of a light ray along a glass corridor where the walls are either parallel or perpendicular to one another. If the angle of incidence at point $P$ is $30^o$,what are the angles of reflection of the light ray at points $Q, R, S$ and $T$ respectively?

$A$ cubical room is formed with $6$ plane mirrors. An insect moves along the diagonal of the floor with uniform speed $v_0$. The speed of its image in two adjacent walls,parallel to the walls,is $20\sqrt{2} \ cm/s$. Then the speed of the image formed on the roof with respect to the ground is ...... $cm/s$.

$A$ watch shows time as $3:25$ when seen through a mirror,the time appeared will be

Which one of the following statements is true?

The separation between the screen and a plane mirror is $2r$. An isotropic point source of light is placed exactly midway between the mirror and the screen. Assume that the mirror reflects $100\%$ of the incident light. Then the ratio of illuminances on the screen with and without the mirror is