Experimental Skills (Physics) · Question 1

Which of the following measurements require 'index correction'?

1. Measurement of speed of sound using resonance tube
2. Measurement of resistance of a wire using meter bridge
3. Measurement of gravitational acceleration using simple pendulum
4. Measurement of focal length of lenses using optical bench

Answer

(4) Measurement of focal length of lenses using optical bench

Solution

In an optical bench experiment, index correction is applied to account for the difference between the actual distance between the optical centre of the lens and the tip of the needle, and the distance measured on the scale of the optical bench.

Answer: (4)