A spherical mirror and a thin spherical lens have each a focal length of$-15 \mathrm{cm}.$  The mirror and the lens are likely to be :

What is meant by the pole of a spherical mirror?

Correct relation between radius of curvature($R$) and Focal length ($F$) of a spherical mirror is:

What will be the angle of incidence when a ray of light passes through the centre of curvature of a concave mirror?

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.

The image of a distant object is obtained on a screen by using a concave mirror. The focal length of the mirror is measured by the distance between