Physics - Electrostatics Question with Solution | TestHub

Force on charge $q$ at $A$ : (i) Due to $B,f=kq\times \frac{q}{r^2}$ or $f=\frac{k{q}^2}{r^2}$ along $BA$ (ii) Due to $C$, $f=\frac{k{q}^2}{r^2}$ along $CA$ Resultant force $=F$ $\begin{array}{rl}& F^2=f^2+f^2+2f\times f\times \cos 60^{\circ }\\ & F^2=2f^2+\frac{2f^2\times 1}{2}=3f^2\text{ or }F=\sqrt{3}f\\ & \text{ or Resultant force }=\sqrt{3}\frac{\mathrm{kq}}{r^2}\end{array}$