Two unit negative charges are placed on a straight line. A positive charge $q$ is placed exactly at the mid point between these unit charges. If the system of these three charges is in equilibrium, the value of $q$ (in $\mathrm{C}$ ) is

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Aicharya · Accepted Answer

For equilibrium, we have

$F_{A B}+F_{A C}=0$ or $\quad \frac{1}{4 \pi \varepsilon_0} \frac{q_1 q}{(d / 2)^2}+\frac{1}{4 \pi \varepsilon_0} \times \frac{q_1 q_2}{d^2}=0$ Given, $\quad q_1=q_2=-1 \mu \mathrm{C}$ So, $\quad-\frac{q}{(d / 2)^2}+\frac{1}{d^2}=0$ $q=\frac{1}{4}=0.25 \mathrm{C}$

Two unit negative charges are placed on a straight line. A positive charge $q$ is placed exactly at the mid…

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