Answer:
-4 Q
Explanation:
We are given that
Positive charge=+Q
Let the distance between positive charge and dot=r
The distance between negative charge q and dot=2r
We know that
Electric field,E=[tex]\frac{KQ}{r^2}[/tex]
Electric field due to positive charge=[tex]E_1=\frac{KQ}{r^2}[/tex] (outward direction)
Electric field due to negative charge q=[tex]E_2=\frac{Kq}{(2r)^2}[/tex](Inward direction)
The direction of E1 and E2 are opposite
According to question
[tex]\frac{KQ}{r^2}-\frac{Kq^2}{(2r)^2}=0[/tex]
[tex]\frac{KQ}{r^2}=\frac{Kq}{(2r)^2}[/tex]
[tex]\frac{q}{4}=Q[/tex]
[tex]q=4Q[/tex]
The charge q is negative therefore, q=-4 Q
