Concepts of Physics

IIT JEE Physics (1978-2018: 41 Years) Topic-wise Complete Solutions

Nature of the Image formed by a Concave Mirror


To study the nature of image formed by a concave mirror.


Concave mirror, mirror stand, a candle, screen



Let us study the nature of the image formed by a concave mirror. First find the approximate focal length \((f)\) of a concave mirror. Then fix it vertically on a stand. Draw a long straight line on a table and place the mirror stand on it. The pole of the mirror should be exactly above the line. Now mark the point F and C on the line, at distances \(f\) and \(2f\) respectively from the mirror.

Make a small screen of stiff paper and fix it on another stand. The screen should be vertical, with its centre at the same height as the pole of the mirror. Place the screen stand on the line drawn on the table.

Light a candle and place it between F and C. The flame of the candle should be at about the same height as the pole of the mirror. Move the screen back and forth till you see an inverted image of the flame on the screen. What is the location of image and is it real, enlarged, and inverted. Keep the candle at different positions and try to get its image on the screen. What are the positions and characteristics of the image?