Write an activity to find the …

o determine focal length of a given concave mirror:

Materials Required
A concave mirror, a measuring scale, a screen a mirror holder and mirror stand.

Procedure

1. Select a distant object from the laboratory window (distance should be more than 50 ft).
2. Fix the concave mirror on the mirror stand placed on the table, facing the distant object.
3. Place the screen in front of the reflecting surface of the mirror. Move the screen back and forth until a clear, sharp image of the distant object is obtained on the screen.
4. Measure the distance between the concave mirror and the screen with a metre scale. This distance is the focal length of the given concave mirror. Record the focal length.
5. Repeat the above procedure twice and record the readings. Take three readings and calculate the average focal length.