# A point charge

Question:

A point charge of $+12 \mu \mathrm{C}$ is at a distance $6 \mathrm{~cm}$ vertically above the centre of a square

of side $12 \mathrm{~cm}$ as shown in figure. The magnitude of the electric flux through the square will be_____ $\times 10^{3} \mathrm{Nm}^{2} / \mathrm{C}$

Solution:

(226)

Using Gauss law, it is a part of cube of side $12 \mathrm{~cm}$ and charge at centre so;

$\phi=\frac{Q}{6 \varepsilon_{0}}=\frac{12 \mu \mathrm{c}}{6 \varepsilon_{0}}=2 \times 4 \pi \times 9 \times 10^{9} \times 10^{-6}$$=226 \times 10^{3} \mathrm{Nm}^{2} / \mathrm{C}$