Question 851: Electrostats & Capacitance

Question

Three point charges $$\mathrm{+Q,+2q}$$ and $$+\mathrm{q}$$ are placed at the vertices of a right angled isosceles triangle. The net electrostatic potential energy of the configuration is zero, if $$Q$$ is equal to

Accepted Answer

Net electrostatic potential energy of the system is,
$$\begin{aligned}
& \quad U=\frac{1}{4 \pi \varepsilon_0}\left(\frac{Q q}{a}+\frac{2 Q q}{a}+\frac{2 q q}{\sqrt{2} a}ight)=0 \
& Q+2 Q+\frac{2 q}{\sqrt{2}}=0 \
& 3 Q+\sqrt{2} q=0 \
& 	herefore \quad Q=\frac{-\sqrt{2} q}{3}
\end{aligned}$$

Answer

$$-\frac{\sqrt{2}}{3} q$$

Answer

$$+\frac{\sqrt{2}}{3} q$$

Answer

$$-\frac{3}{\sqrt{2}} q$$

Answer

$$+\frac{3}{\sqrt{2}} \mathrm{q}$$

Electrostats & Capacitance

Three point charges $\mathrm{+Q,+2q} and +\mathrm{q} are placed at the vertices of a right angled isosceles triangle. The net electrostatic potential energy of the configuration is zero, if Q$ is equal to

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