Question 716: Electrostats & Capacitance

Question

Suppose a uniformly charged wall provides a uniform electric field of $2 	imes 10^4 \mathrm{~N} / \mathrm{C}$ normally. A charged particle of mass $2 \mathrm{~g}$ being suspended through a silk thread of length $20 \mathrm{~cm}$ and remain stayed at a distance of $10 \mathrm{~cm}$ from the wall. Then the charge on the particle will be $\frac{1}{\sqrt{x}} \mu \mathrm{C}$ where $x=$ ___________ . [use $\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2$ ]

Accepted Answer

$\begin{aligned} & \sin 	heta=\frac{10}{20}=\frac{1}{2} \\ & 	heta=30^{\circ} \\ & 	an 	heta=\frac{\mathrm{qE}}{\mathrm{mg}} \\ & 	an 30^{\circ}=\frac{\mathrm{q} 	imes 2 	imes 10^4}{1 	imes 10^{-3} 	imes 10}\end{aligned}$
$\begin{aligned} & \frac{1}{\sqrt{3}}=q 	imes 10^6 \\ & q=\frac{1}{\sqrt{3}} 	imes 10^{-6} C \\ & x=3\end{aligned}$

Electrostats & Capacitance

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