GATE 2022 BM – Question 59
A moving-coil voltmeter has internal resistance 50 Ω and 100 equal scale divisions. A 1 V input gives full-scale deflection of 100 divisions. What series resistance in Ω makes 500 V give the same full-scale deflection?
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Correct answer: 24950 to 24950
Explanation
Full-scale current is Ifs=1/50=.02 A. At five hundred volts the required total resistance is 500/.02=25000 Ω. Subtract the existing fifty-ohm meter resistance to obtain the added series resistance: 25000−50=24950 Ω.