Real Lab Procedure
- Place a thin convex lens vertically on a lens holder kept on a table. The lens should face a distant object outside the window (a tree or an electricity pole or a distant building).
- Place a screen fixed on a stand on the other side of the lens. Move the screen back and forth to obtain a sharp, clear and inverted image of the distant object.
- Measure the distance between the screen and the optical centre of the convex lens using a measuring scale. Record the observation as the focal length of the lens.
- Repeat the experiment at least 3 times and record it in the observation table.
- Find the mean value of focal length.
||Name of the distant object
||Distance between the convex lens and the screen (f)
||Mean focal length of the convex lens, f
The focal length of the given convex lens is _________.