Capacitance is defined as the relationship between charge and voltage as

• A. Q divided by V.
• B. V divided by Q.
• C. Q times V.
• D. 1 divided by (Q times V).

Answer: (A)

Capacitance tells us how much charge a capacitor can store for a given voltage. For an ideal capacitor, the stored charge and the voltage are directly proportional: Q = C V. The capacitance C is defined as the ratio of charge to voltage, so C = Q / V. That makes Q divided by V the correct expression.

In words, a farad is one coulomb per volt, which is why C = Q / V is a constant for a given capacitor. If you take V divided by Q, you’d get the reciprocal of capacitance, not the capacitance itself. Multiplying Q and V or taking 1/(Q V) doesn’t describe the stored-charge–per–voltage relationship.