Voltage as electric potential difference Steps:

• Recall that voltage measures the potential energy difference per unit charge in an electric field.
• Use the definition: electric potential difference V = work done (energy) / charge, or V = W / Q.
• Work is in joules (J), charge in coulombs (C), so V = J/C.
• Thus, 1 volt = 1 J/C.

Why A is correct:

• Voltage is defined as potential energy per unit charge, so 1 V = 1 J/C by the formula V = W/Q.

Why the others are wrong:

• B: One coulomb per second defines current (ampere, A), not voltage.
• C: One joule per second defines power (watt, W), not voltage.
• D: One joule second per coulomb squared relates to inductance or magnetic flux, not voltage.

Final answer: A