Q. Two charges $q $ and $-2q$ are separated by a distance $d$. If the electric intensity at the site of $q$ is $E$ then electric field at the site of $-2q$ is ·

In This post you will get answer of Q.
Two charges $q $ and $-2q$ are separated by a distance $d$. If the electric intensity at the site of $q$ is $E$ then electric field at the site of $-2q$ is ·

Solution:

Given situation is shown in the figure,

Also, net electric field at the site of charge q is E.

$E = frac{-2q }{4 pi varepsilon_0 d^2} , , , , , , , , , , , , , , , , , $ …(i)

Net electric field at the site of $-2q$ is $E’$ (say).

$therefore : E = frac{q}{4 pi varepsilon_0 d^2} , , , , , , , , , , , , , , , , , $ …(ii)

From eq. (i) and (ii),

$E’ = – frac{E}{2}$