$A$ plane mirror makes an angle of $30^\circ$ with the horizontal. $A$ vertical ray is incident on the mirror. What is the angle between the mirror and the reflected ray in degrees?

An object is placed between two plane mirrors inclined at some angle to each other. If the number of images formed is $7$, then the angle of inclination is: (in $^{\circ}$)

$A$ small plane mirror is placed at the centre of a spherical screen of radius $R$. $A$ beam of light is falling on the mirror. If the mirror makes $n$ revolutions per second,the speed of the reflected light spot on the screen will be:

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

$A$ point source of light $S$ is placed at a distance $10\,cm$ in front of the centre of a mirror of width $20\,cm$ suspended vertically on a wall. $A$ man walks with a speed $10\,cm/s$ in front of the mirror along a line parallel to the mirror at a distance $20\,cm$ from it as shown in the figure. Find the maximum time during which he can see the image of the source $S$ in the mirror. (in $,s$)

The figure shows two rays $A$ and $B$ being reflected by a mirror and emerging as $A'$ and $B'$. The mirror