EXERCISE

The radius of curvature of a concave mirror is the distance from the _____ to the _____ of the mirror.

The nature of image formed by a concave mirror of focal length $25 \mathrm{cm}$, of an object placed at $50 \mathrm{cm}$ from the mirror, is _____ and _____.

Ryan stands in front of three huge mirrors $- \mathrm{A}, \mathrm{B}$ and $\mathrm{C}$ at such a distance from them that he can see the erect image of his face in all three mirrors. He slowly starts walking towards the mirrors and finds that in mirrors $\mathrm{A}$ and$\mathrm{B}$, the size of his face goes on increasing while in the mirror $\mathrm{C}$, the size of his face remains the same. He also notices that the size of his face in the mirror $\mathrm{A}$ is bigger than the actual size of his face while in mirror $\mathrm{B}$, the size of his face is smaller than the actual size of his face. State the type of each of the mirrors $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$.

For a converging mirror of focal length $20 \mathrm{cm}$, find all the possible positions of the object for which the image is twice as large as the object.

An object kept at a distance of $25 \mathrm{cm}$ from a spherical mirror produces a virtual image that is $20 \mathrm{cm}$ behind the mirror. Find the magnification of the image and the type of mirror.

The radius of curvature of a dentist's mirror is $2.8 \mathrm{cm}$. If the dentist wants a four times magnified virtual image of a small dental cavity, how far should the mirror be placed from the cavity?

The focal length of a rear-view convex mirror of a car moving at a speed of $40 \mathrm{km}/\mathrm{hr}$ is $1 \mathrm{m}$. A bus is following the car at a distance of $4 \mathrm{m}$ with the same speed. What are the position and the nature of the image formed? Also find the size of the bus image relative to the actual size of the bus.

A security mirror in the car park of a building is $4 \mathrm{m}$ away from a Porsche car. If the mirror produced one-ninth magnification, calculate the radius of curvature of the mirror.