Question

Three charges \(q_1 = 1~\mu C,~q_2=-2~\mu C, ~q_3=2~\mu C\), are placed at the vertices of an equilateral triangle of side 1m. The magnitude of net electric force in newton on charge \(q_1\) is

Answer 1

This problem is based on the principle of superposition of electric forces
\(F_{13}=9 \times 10^9 \frac{(1 \times 10^{-6})(2 \times 10^{-6})}{1^2}\)
\(=18 \times 10^{-3}\)
\(F_{12} = 9 \times 10^4 \frac{(1 \times 10^{-6})(2 \times 10^{-6})}{1^2}\)
\(=18 \times 10^{-3}\)
\(F_{net}\) on \(q_1\) is F
\(=\sqrt{(18 \times 10^{-3})^2 + (18 \times 10^{-3})^2+2(18 \times 10^{-3})^2 cos~120^\circ}\)
\(=18.0 \times 10^{-3}~N\)