Two plane mirrors are kept on a horizontal table making an angle $\theta$ with each other as shown schematically in the figure. The angle $\theta$ is such that any ray of light reflected after striking both the mirrors returns parallel to its incident path. For this to happen,the value of $\theta$ should be (in $^{\circ}$)

$A$ thick plane mirror shows a number of images of the filament of an electric bulb. Of these,the brightest image is the

Two plane mirrors $A$ and $B$ are aligned parallel to each other,as shown in the figure. $A$ light ray is incident at an angle of $30^\circ$ at a point just inside one end of $A$. The plane of incidence coincides with the plane of the figure. The maximum number of times the ray undergoes reflections (including the first one) before it emerges out is

If there are mirrors on the ceiling and two adjacent walls of a room,how many images of a person in the room will be visible?

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

$A$ point object is kept in front of a plane mirror. The plane mirror is performing $SHM$ with an amplitude of $2 \ cm$. The plane mirror moves along the $x$-axis,and the $x$-axis is normal to the mirror. The amplitude of the mirror is such that the object is always in front of the mirror. The amplitude of the $SHM$ of the image is ....... $cm$.