If you double the area AND distance between two circular plates in a capacitor, what happens to the capacitance?

If you double the area AND distance between two circular plates in a capacitor, what happens to the capacitance?

• A. It stays the same
• B. It doubles
• C. It halves
• D. It quadruples

Answer: (A)

The capacitance of a parallel-plate capacitor depends on the plate area and their separation, following C = ε A / d for a given dielectric. If you double the area and also double the distance, the new capacitance is C' = ε (2A) / (2d) = ε A / d = C. The two changes cancel each other, so the capacitance stays the same. This illustrates how C scales with A and inversely with d: proportional changes in A and d by the same factor leave C unchanged.

The capacitance of a parallel-plate capacitor depends on the plate area and their separation, following C = ε A / d for a given dielectric. If you double the area and also double the distance, the new capacitance is C' = ε (2A) / (2d) = ε A / d = C. The two changes cancel each other, so the capacitance stays the same. This illustrates how C scales with A and inversely with d: proportional changes in A and d by the same factor leave C unchanged.