If the charge on a capacitor doubles while the voltage remains constant, what happens to capacitance?

If the charge on a capacitor doubles while the voltage remains constant, what happens to capacitance?

• A. Decrease
• B. Remain the same
• C. Increase
• D. Become negative

Answer: (C)

Capacitance is defined by the relation Q = C V, so for a given capacitor, the charge and voltage are linked by the ratio C = Q / V. If the voltage stays the same and the charge doubles, the ratio Q / V doubles as well, meaning the capacitance must increase. In other words, with the same applied voltage, storing twice as much charge requires twice the capacitance. Note that in real devices, capacitance is determined by the capacitor’s geometry and dielectric and is typically a constant for a given component; this scenario is a way to apply the formula and see how Q and V relate to C.

Capacitance is defined by the relation Q = C V, so for a given capacitor, the charge and voltage are linked by the ratio C = Q / V. If the voltage stays the same and the charge doubles, the ratio Q / V doubles as well, meaning the capacitance must increase. In other words, with the same applied voltage, storing twice as much charge requires twice the capacitance.

Note that in real devices, capacitance is determined by the capacitor’s geometry and dielectric and is typically a constant for a given component; this scenario is a way to apply the formula and see how Q and V relate to C.