Briefly explain activity to find foxal length
Answers
Answer:
Turn the face of mirror towards a distant object (may be candle). Now adjust the screen ,candle and the mounted concave mirror so that they are all on the principal axis. Measure the distance between the concave mirror and the screen with a metre scale. Record your observations in observation table.
We can find the focal length of concave mirror and convex lens using the activity. To nd the focal length of convex mirror and concave lens you will need to use the mirror formula. You cannot find the focal length of convex mirror and concave lens using simple activity. The method of finding the focal length of concave mirror is given below.
1. Fix concave mirror to mirror holder and place it on a plane surface say a long table. Turn the face of mirror towards a distant object may be candle.
2. Now adjust the screen candle and the mounted concave mirror so that they are all on the principal axis.
3. Move the screen back and forth and determine the position for the brightest clearest image
4. Measure the distance between the concave mirror and the screen with a metre scale. Record your observations in the observation table.
5. Repeat the experiment two or three times and find the mean value of the focal length. We can use the same method to find the focal length of convex lens.