Two small balls, each carrying a charge q are suspended by equal insulator strings of length l m from the hook of a stand. This arrangement is carried in a satellite in space. The tension in each string will be

$\frac{1}{4 {πε}_{0}} \frac{q}{l^{2}}$

$\frac{1}{4 {πε}_{0}} \frac{q^{2}}{4 l^{2}}$

$\frac{1}{4 {πε}_{0}} \frac{q^{2}}{l^{2}}$

$\frac{1}{(4 {πε}_{0})} \frac{q}{l}$

Solution

$\frac{1}{4 {πε}_{0}} \frac{q^{2}}{4 l^{2}}$

Suppose, T be the tension in the spring T. Also in the satellite, two balls will be in a straight line.

So, force acting on the balls
F = $\frac{1}{4 {πε}_{0}} \frac{q^{2}}{{(2 l)}^{2}}$ ......(i)

This force will be balanced by tension in the string

T = F ......(ii)

Now from equatin (i) and (ii) we get

T = $\frac{1}{4 {πε}_{0}} \frac{q^{2}}{4 l^{2}}$

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