A galvanometer with coil resistance 15 Ohm gives full-scale deflection when 5 mA flows through it. What series resistance must be added to convert it into a voltmeter reading 0 to 10 V?

2.535 * 10³ Ohm
4.005 * 10³ Ohm
1.985 * 10³ Ohm
2.045 * 10³ Ohm

Correct answer: 1.985 * 10³ Ohm

Solution

The series resistor and galvanometer must drop 10 V at the full-scale current of 5 mA, giving total 2000 Ohm, of which 15 Ohm is the coil.

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