Solution:
Current through the galvanometer,
Current for 30 divisions
Current for 20 divisions =
For the same deflection to obtain for 20 division, let resistance added be R.
A galvanometer of resistance is connected to a battery of 3 V along with a resistance of in series. A full-scale deflection of 30 divisions is obtained in the galvanometer. In order to reduce this deflection to 20 divisions, the resistance in series should be
Current through the galvanometer,
Current for 30 divisions
Current for 20 divisions =
For the same deflection to obtain for 20 division, let resistance added be R.