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In a portion of a circuit, an ammeter reads 5 A while a voltmeter of resistance 480 ohm, connected in parallel with a resistor R, reads 96 V. The ammeter measures the total current entering the parallel combination. Find R.

1. 20 ohm
2. 24 ohm
3. 32 ohm
4. 16 ohm

Correct answer: 20 ohm

Solution

The voltmeter draws 0.2 A, so R carries 4.8 A at 96 V, giving R = 96/4.8 = 20 ohm.

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