If the plate area is doubled while the distance between plates remains the same, what happens to the capacitance?

• A. It remains the same
• B. It doubles
• C. It increases by a factor of four
• D. It becomes zero

Answer: (B)

Capacitance in a parallel-plate capacitor is proportional to plate area when the distance and dielectric stay fixed: C = ε0 A / d (or C = κε0 A / d). Doubling the area increases the numerator while the denominator stays the same, so the capacitance doubles. The other options would require changing the distance or the dielectric, which isn’t happening here, so the capacitance simply becomes twice as large.