To get three images of a single object, one should have two plane mirrors at an angle of $...^\circ$.

Two plane mirrors are inclined at an angle of $72^{\circ}$. The number of images of a point object placed between them will be

$A$ light ray is incident perpendicular to the plane of a mirror. The angle of reflection will be ......$^o$.

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

Assertion : The image of a virtual object due to a plane mirror is real.
Reason : If the rays seem to be converging at a point behind a plane mirror,they are reflected and they actually meet in front of the mirror.

$A$ light ray makes an angle of $10^{\circ}$ with the horizontal. It is incident on a plane mirror which makes an angle $\theta$ with the horizontal. If the reflected ray travels in the vertically upward direction,then $\theta = .....^{\circ}$