How is capacitance C defined?

How is capacitance C defined?

• A. C = V / Q
• B. C = Q V
• C. C = Q / V
• D. C = Q^2 / V

Answer: (C)

Capacitance tells you how much charge a capacitor stores per volt of potential difference across its plates. The defining relation is C = Q / V, where Q is the magnitude of the charge on one plate and V is the potential difference between the plates. This means the charge relates to voltage through Q = C V, and the voltage relates to charge via V = Q / C. In a simple geometry like a parallel-plate capacitor, C depends on the geometry and dielectric (for vacuum, C = ε0 A / d), so increasing plate area or the dielectric constant, or decreasing separation, increases C. Other forms don’t yield the correct units or the correct proportionality between charge and voltage.

Capacitance tells you how much charge a capacitor stores per volt of potential difference across its plates. The defining relation is C = Q / V, where Q is the magnitude of the charge on one plate and V is the potential difference between the plates. This means the charge relates to voltage through Q = C V, and the voltage relates to charge via V = Q / C. In a simple geometry like a parallel-plate capacitor, C depends on the geometry and dielectric (for vacuum, C = ε0 A / d), so increasing plate area or the dielectric constant, or decreasing separation, increases C. Other forms don’t yield the correct units or the correct proportionality between charge and voltage.