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An instantaneous displacement current of 1.0 A is to be produced in the gap of a 1 microfarad parallel-plate capacitor. At what rate must the potential difference across the capacitor be changing?

1. 10⁶ V/s
2. 10³ V/s
3. 10⁸ V/s
4. 10⁹ V/s

Correct answer: 10⁶ V/s

Solution

The conduction current charging a capacitor equals the displacement current between the plates, I = C dV/dt. With I = 1 A and C = 1 microfarad = 10⁻⁶ F, dV/dt = 1 / 10⁻⁶ = 10⁶ V/s.

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