Question

The variation of potential with distance r from a fixed point is shown in Figure. The electric field at $r=5$cm, is?

• A. $\left(2.5\right)V/cm$
• B. $(-2.5)V/cm$
• C. $(-2/5)cm$
• D. $\left(2/5\right)V/cm$

Answer 1

The correct option is A $\left(2.5\right)V/cm$

We know that, Electric field intensity, E=-$\frac{dV}{dr}$ , where V is the potential.

Here from the graph, it is clear that, at the distance r= 5 cm potential is 2.5V.

Electric field intensity, E= $\frac{-(0-5)V}{(6-4)cm}=\frac{5}{2}$

=2.5 V/cm