Measuring Devices ( Galvanometer, Voltmeter and Ammeter & Meter Bridge ): Practice Problem & Solution
Current sensitivity of a moving coil galvanometer is $5 \text{ div/mA}$ and its voltage sensitivity (angular deflection per unit voltage applied) is $20 \text{ div/V}$. The resistance of the galvanometer is: (2018)
Solution Explained:
To solve this problem, we apply the core principles of Measuring Devices ( Galvanometer, Voltmeter and Ammeter & Meter Bridge ). Understanding the underlying formula is key to arriving at the correct answer below:
Resistance is the ratio of current sensitivity to voltage sensitivity: $R = \frac{I_s}{V_s} = \frac{5 \text{ div/mA}}{20 \text{ div/V}} = \frac{5000 \text{ div/A}}{20 \text{ div/V}} = 250 \text{ } \Omega$.
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