Explain image formation for the following in case of concave mirror. Make suitable ray diagrams.
Object is at focus.

The radius of curvature of a converging mirror is $30 \mathrm{cm}$. At what distance from the mirror should an object be placed so as to obtain a virtual image?

Which of the following statements is not true in reference to the diagram shown above?

If a mirror forms erect image for objects placed between pole and focus, and it forms real-inverted image for object placed anywhere between focus and infinity, then the mirror is:

A student holding a mirror in his hand, directed the reflecting surface of the mirror towards the Sun. He then directed the reflected light on to a sheet of paper held close to the mirror.

Which type of mirror does he have?

An object of height $4 \mathrm{cm}$ is kept at a distance of $30 \mathrm{cm}$ from the pole of a diverging mirror. If the focal length of the mirror is $10 \mathrm{cm}$, the height of the image formed is ____.

Which effect is responsible for blue colour of smoke?

In which of the following is a concave mirror is used?

What should he do to burn the paper?

Focal length of one convex mirror is $3 \mathrm{m}$ and object distance is $5 \mathrm{m}$, then find the image distance.

For the diagram shown, according to the new Cartesian sign convention the magnification of the image formed will have the following specifications.

A student holding a mirror in his hand, directed the reflecting surface of the mirror towards the Sun. He then directed the reflected light on to a sheet of paper held close to the mirror.

Will he be able to determine the approximate value of focal length of this mirror from this activity ? Give reason and draw ray diagram to justify your answer in this case.