Question
Describe how can the focal length of a concave mirror be determined experimentally.
Answer
A rough estimation of the focal length of a concave mirror can be done by holding a concave mirror facing a window in a room. The position and inclination of the mirror are so adjusted that a sharp image of the window is formed on the opposite wall. Parallel rays coming from the window falling On The Mirror would converge on the wall at the focus of the mirror. When a sharp image of the window is formed on the opposite wall. The distance between the mirror and the wall is determined by the scale. This gives the approximate focal length of the mirror.
