The work done in moving a charge of 2 coulomb (C) from point A to point B is 24 J. What is the potential difference between A and B?
- A.48 V
- B.6 V
- C.12 V
- D.0.08 V
Correct answer
Explanation
The correct answer is C, 12 V. Potential difference is the work done per unit charge, so V = W/Q = 24 J ÷ 2 C = 12 V.
The potential difference between two points is the work needed to move one coulomb of charge from one point to the other. Its SI unit is the volt, named after Alessandro Volta, and 1 volt equals 1 joule per coulomb. Here 24 joules of work move 2 coulombs, so each coulomb needs 12 joules, which is 12 volts. The same relation, W = VQ, gives the energy a battery supplies when charge flows through a circuit, and it is measured with a voltmeter connected in parallel.
A is wrong because 48 V comes from multiplying work and charge instead of dividing. B is wrong because 6 V would mean only 12 J of work for 2 C. D is wrong because 0.08 V comes from dividing the charge by the work, which turns the formula upside down.
Exam tip: V = W/Q; 1 volt = 1 joule per coulomb; a voltmeter is joined in parallel, an ammeter in series.
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