- Home
- Standard 12
- Physics
Suppose a uniformly charged wall provides a uniform electric field of $2 \times 10^4 \mathrm{~N} / \mathrm{C}$ 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 $\frac{1}{\sqrt{\mathrm{x}}} \ \mu \mathrm{C}$ where $\mathrm{x}=$ ____________. use $g=10 \mathrm{~m} / \mathrm{s}^2$ ]
$2$
$3$
$4$
$5$
Solution
$\sin \theta=\frac{10}{20}=\frac{1}{2}$
$\theta=30^{\circ}$
$\tan \theta=\frac{\mathrm{qE}}{\mathrm{mg}}$
$\tan 30^{\circ}=\frac{\mathrm{q} \times 2 \times 10^4}{1 \times 10^{-3} \times 10}$
$\frac{1}{\sqrt{3}}=\mathrm{q} \times 10^6$
$\mathrm{q}=\frac{1}{\sqrt{3}} \times 10^{-6} \mathrm{C}$
$x=3$
