Question 766: Electrostats & Capacitance

Question

Three charges $Q(-2 q)$ and $(-2 q)$ are placed at the vertices of an isosceles right angled triangle as shown in figure. The net electrostatic potential energy is zero if $Q$ is equal to

Accepted Answer

$$ \begin{aligned} &\because \quad 	ext { Total potential energy }\ &\begin{array}{ll} \quad & \mathrm{U}_{	ext  {Toal }}=\mathrm{U}_{12}+\mathrm{U}_{13}+\mathrm{U}_{23}=0\,\,\,\,\,\,\,\,  	ext { ...(given) } \ 	herefore&    \mathrm{U}_{	ext {Total }}=-\frac{2 \mathrm{kQq}^2}{l}-\frac{2 \mathrm{kQq}^2}{l}+\frac{4 \mathrm{kq}^2}{l \sqrt{2}}=0 \ & \frac{4 \mathrm{kq}^2}{l \sqrt{2}}=\frac{4 \mathrm{kQq}^2}{l} \ & \mathrm{Q}=\frac{4 \mathrm{kq}^2}{l \sqrt{2}} \cdot \frac{l}{4 \mathrm{kq}}=\frac{\mathrm{q}}{\sqrt{2}} \end{array} \end{aligned} $$

Answer

$\sqrt{2} q$

Answer

$\frac{\mathrm{q}}{2}$

Answer

$\frac{\mathrm{q}}{\sqrt{2}}$

Answer

$\frac{q}{2 \sqrt{2}}$

Electrostats & Capacitance

Three charges Q(-2 q) and (-2 q) are placed at the vertices of an isosceles right angled triangle as shown in figure. The net electrostatic potential energy is zero if Q is equal to

Choose the correct answer: