Question

Electric potential at any point is $V = - 5x + 3y + \sqrt {15 z},$then the magnitude of the electric field is

• A. $3\sqrt {2}$
• B. $4\sqrt {2}$
• C. $5\sqrt {2}$
• D. 7

Answer 1

Answer: (D)

7

Answer 2

$E_{x}=-\frac{r v}{r x}=\frac{-r}{r x}(-5 x+5 y+\sqrt{15 z})=5$
$E_{y}=\frac{r v}{r y}=-3 E_{z}=-\sqrt{15}$
Now, $E=\sqrt{E_{y}^{x}}+E_{y}^{z}+E_{z}^{z}=7$