Question

neutral point betwewen two chrges q and -4q

Answer 1

Neutral Point:

• Let's assume that the charges q and -4q are separated by a distance d.

• Now, the position of the neutral point will be as follows (see diagram):

• Neutral point will be at Point A.

$\therefore \: E1 = E2$

$\implies \: \dfrac{kq}{ {x}^{2} } = \dfrac{k(4q)}{ {(x + d)}^{2} }$

$\implies \: \dfrac{1}{ {x}^{2} } = \dfrac{4}{ {(x + d)}^{2} }$

Taking square root on both sides:

$\implies \: \dfrac{1}{x } = \dfrac{2}{x + d}$

$\implies \: 2x = x + d$

$\implies \: x = d$

So, the neutral point will be 'd' units away from charge q and (d + d) = 2d units from -4q.