Which statement best describes how capacitance changes with plate area and separation?

Which statement best describes how capacitance changes with plate area and separation?

• A. Capacitance is independent of plate area and separation.
• B. Capacitance depends only on the material between plates.
• C. Capacitance decreases with larger plate area and increases with greater separation.
• D. Capacitance increases with larger plate area and decreases with greater separation.

Answer: (D)

Capacitance tells us how much charge a capacitor can store per volt, and for a simple parallel-plate capacitor it scales with area and gap as C ∝ A/d (with a factor of the dielectric if present). More plate area means more room to hold charge at a given voltage, so the capacitance increases. Larger separation between the plates weakens the electric field across the gap, so you store less charge for the same voltage, and the capacitance decreases. In practical terms, doubling the plate area doubles the capacitance, while doubling the separation halves it. The dielectric between the plates can further modify this by multiplying C by the dielectric constant, but the main dependence on area and separation is as described.

Capacitance tells us how much charge a capacitor can store per volt, and for a simple parallel-plate capacitor it scales with area and gap as C ∝ A/d (with a factor of the dielectric if present). More plate area means more room to hold charge at a given voltage, so the capacitance increases. Larger separation between the plates weakens the electric field across the gap, so you store less charge for the same voltage, and the capacitance decreases. In practical terms, doubling the plate area doubles the capacitance, while doubling the separation halves it. The dielectric between the plates can further modify this by multiplying C by the dielectric constant, but the main dependence on area and separation is as described.