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2. Electric Potential and Capacitance
medium
If $OP = 1\,\,cm$ and $OS = 2\,\, cm$, work done by electric field in shifting a point charge $\frac {4\sqrt 2}{27}\,\, μC$ from point $P$ to $S$ in given figure is
A
$\frac {100}{3} \,\,J$
B
$\frac {200}{3} \,\,J$
C
$100\,\,J$
D
$200\,\,J$
Solution
$\mathrm{W}_{\mathrm{ef}}=-(\Delta \mathrm{U})=-q\Delta \mathrm{V}=\mathrm{PE}_{\mathrm{i}}-\mathrm{PE}_{\mathrm{f}}$
$=q\left\{\frac{\mathrm{KP} \cos 45^{\circ}}{\left(1 \times 10^{-2}\right)^{2}}-\frac{\mathrm{KP} \cos 135^{\circ}}{\left(2 \times 10^{-2}\right)^{2}}\right\}=\frac{100}{3} \mathrm{\,J}$
Standard 12
Physics
