Voltage Definition in Terms of Energy and Charge

Steps:

• Recall the definition of electric potential difference: voltage measures energy per unit charge.
• Voltage V equals work done W divided by charge Q, so V = W/Q.
• Work is in joules (J) and charge in coulombs (C), yielding V = J/C.
• Thus, 1 volt equals 1 J/C.

Why A is correct:

• By definition, 1 volt is the potential difference when 1 joule of work is done per coulomb of charge moved.

Why the others are wrong:

• B defines current (ampere), not voltage.
• C defines power (watt), not voltage.
• D resembles the inverse of capacitance or unrelated unit, not voltage.

Final answer: A