$A$ 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 $,s$)

Light of wavelength $5000 \,\mathring{A}$ falls on a plane reflecting surface. What are the wavelength and frequency of the reflected light? For what angle of incidence is the reflected ray normal to the incident ray?

The image of an object $O$ due to reflection from the surface of a lake is elongated due to the ripples on the water surface caused by a light breeze. This is because the ripples act as tilted mirrors as shown below. Consider the case,where $O$ and the observer $E$ are at the same height above the surface of the lake. If the maximum angle that the ripples make with the horizontal is $\alpha$,then the angular extent $\delta$ of the image will be

The rear window of a car has a size of $120 \, cm \times 45 \, cm$. The driver sits at a distance $L = 2 \, m$ from the rear window. What should be the minimum size of a flat mirror,hanging at a distance of $0.5 \, m$ in front of the driver,so that he has the best view of the road situation behind the car?

By what angle should $M_2$ be rotated,so that the light ray after reflection from both mirrors becomes horizontal? (The angle of incidence at mirror $M_1$ is $40^{\circ}$ and the angle between $M_2$ and the horizontal is $25^{\circ}$ as shown in the figure.)

Assertion : If the angle between the two plane mirrors is $72^o$ and the object is asymmetrically placed between the two mirrors,then $5$ images of the object will be formed.
Reason : For a given system of mirrors,the total number of images formed due to successive reflection is equal to either $\frac{360^o}{\theta}$ or $\frac{360^o}{\theta} - 1$ accordingly as $\frac{360^o}{\theta}$ is odd or even respectively.