Measuring Devices ( Galvanometer, Voltmeter and Ammeter & Meter Bridge ): Practice Problem & Solution
A galvanometer has a coil of resistance $100 \Omega$ and gives a full scale deflection for $30 \text{ mA}$ current. If it is to work as a voltmeter of $30 \text{ V}$ volt range, the resistance required to be added will be : (2010 Pre)
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:
The required series resistance is $R = \frac{V}{I_g} - G = \frac{30}{30 \times 10^{-3}} - 100 = 1000 - 100 = 900 \Omega$.
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