Question

Let V and E be the potential and the field respectively at a point. Which of the following assertions are correct?

• A. If E $\ne$ 0, V cannot be zero.
• B. none of these.
• C. If V $=$ 0, E must be zero.
• D. If V $\ne$ 0, E cannot be zero.

Answer 1

Answer: (B)

The electric field is $E=-\frac{dV}{dx}$
if $V=0$, we can not say E must be zero, we say only E may be zero.
if $V\ne 0$, E must be zero when V is max i.e, $\frac{dV}{dx}=0$
if $E\ne 0$ , V may be zero when two equal and opposite charges separated by a distance and at the midpoint in between the charges field non-zero but potential is zero.