Three point charges $+q,+2 q$ and $+4 q$ are placed along a straight line such that the charge $+2 q$ lies at equidistant from the other two charges. The ratio of the net electrostatic force on charges $+q$ and $+4 q$ is

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Aicharya · Accepted Answer

$\begin{aligned} & F_1=\frac{k(q)(2 q)}{r^2}+\frac{k(q)(4 q)}{4 r^2}=\frac{12 \mathrm{kq}^2}{4 r^2} \\ & F_2=\frac{k(4 q)(2 q)}{r^2}+\frac{k(4 q)(q)}{4 r^2}=\frac{36 \mathrm{kq}^2}{4 r^2} \\ & \therefore \frac{F_1}{F_2}=\frac{12}{36}=1: 3\end{aligned}$

Three point charges $+q,+2 q$ and $+4 q$ are placed along a straight line such that the charge $+2 q$ lies…

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