The light rays from an object have been reflected towards an observer from a standard flat mirror. The image observed by the observer is:

What should be the angle between two plane mirrors so that whatever be the angle of incidence,the incident ray and the reflected ray from the two mirrors are parallel to each other (in $^o$)?

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?

$A$ ray of light is reflected by a plane mirror. $\hat{e}_0$, $\hat{e}$ and $\hat{n}$ be the unit vectors along the incident ray, reflected ray and the normal to the reflecting surface respectively. Which of the following gives an expression for $\hat{e}$?

Each of these diagrams is supposed to show two different rays being reflected from the same point on the same plane mirror. Which one of the following is correct?

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