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A galvanometer of resistance 25 ohm shows full-scale deflection at a current of 10 mA. To convert it into a voltmeter reading up to 100 V, a resistance R is connected in series with the coil. Find R (in ohm).
- 10000
- 10025
- 975
- 9975
Correct answer: 9975
Solution
Total resistance needed = V/Ig = 100/0.01 = 10000 ohm; subtract the galvanometer's 25 ohm to get R = 9975 ohm.
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