Two point charges + 8 q and -2 q are located at x = 0 and x = L respectively. The location of a point on the x-axis at which the net electric field due to these two point charges is zero is
Answer & explanation
Correct answer: option 1
Let electric field is zero at a distane x from -2q charge.
$\frac{K.2q}{4\pi \epsilon_0 x^2} = \frac{K 8q}{4\pi \epsilon_0 (x+L)^2}$
$\Rightarrow (x+L)^2 = 4 x^2$
$\Rightarrow (x+L) = \pm 2x$
$\Rightarrow x = L $
Distance of point from origin i.e from 8q is 2L.