Basic Galvanometer

Current sensitivity , so if doubles, also doubles.
Voltage sensitivity , since both and double, the effect cancels: remains unchanged.
Therefore, current sensitivity doubles, voltage sensitivity remains the same.

To convert a galvanometer into a voltmeter, a high resistance is connected in series to allow the galvanometer to measure a maximum voltage when its full-scale deflection current flows. The galvanometer’s resistance is , and the voltage across the series combination is: Given: - Maximum current: - Galvanometer resistance: - Voltmeter range: Substitute the values: Alternatively, verify the total resistance required: Thus, the series resistance is 19,985 . Option (4) is correct. Options (1), (2), and (3) do not satisfy the equation.