Question

The gradient of the magnetic vector potential can be expressed as

(a) –με dV/dt

(b) +με dE/dt

(c) –με dA/dt

(d) +με dB/dt

This question was posed to me during an online interview.

This key question is from Maxwell Law in Time Varying Fields topic in chapter Maxwell Equations of Electromagnetic Theory

Answer 1

Right answer is (a) –με dV/dt

To explain: The gradient of A is the ratio of the negative gradient of electric potential to the speed of light c. We can write c = 1/√(με). Thus grad(A) = -με dV/dt is the required expression.