Question

Two-point charges, $q_1 = 36\ \mu\text{C}$ and $q_2 = -9\ \mu\text{C}$ are placed at a distance of $30\text{ cm}$. What distance from $q_1$, where the net electric field is zero, will be:

• A. $10\text{ cm}$
• B. $20\text{ cm}$
• C. $60\text{ cm}$
• D. $30\text{ cm}$

Hint:

For two point charges $q_1$ and $q_2$ separated by $r$, the distance of the neutral point from the smaller charge $q_2$ is $x = \frac{r}{\sqrt{q_1/q_2} \pm 1}$. Use $+$ if charges are opposite, $-$ if they are same.

Answer 1

The Correct Option is C