Four students A, B, C and D performed the experiment to determine the focal length of a concave mirror by obtaining the image of a distant tree on a screen. They measured the distances between the screen and the mirror as shown in the above figure.

The correct way of measuring accurate focal length of the mirror is

Which of the following is a concave mirror?

which of the following is not a property of the image formed by a [lane mirror?

Bouncing of a light ray when it strikes a reflecting surface is called.........