Question

The electrical potential function for an electrical field directed parallel to the x-axis is shown in Fig. The magnitude of the electric field in the x-direction in the interval $4\le x\le 8$ is :

• A. $2.5N{C}^{-1}$
• B. $5N{C}^{-1}$
• C. $-2.5N{C}^{-1}$
• D. $-5N{C}^{-1}$

Answer 1

Answer: (B)

$5N{C}^{-1}$

We know that,
$\overrightarrow{E}=-\frac{dV}{dx}\hat{n}$
Therefore for region $4\le x\le 8$ slope of potential curve is $-5$
and its negative is $5$ . therefore electric field in that region is $5$ N/C