Physics - Electrostatics Question with Solution | TestHub

We can consider all the charge inside the sphere to be concentrated on the centre of sphere. Consider an elementary shell of radius x and thickness dx .

$\mathrm{E}=\frac{\mathrm{K}\int \mathrm{dq}}{{\mathrm{r}}^2}=\frac{\mathrm{K}\int 4\pi {\mathrm{x}}^2\mathrm{dx}(\alpha \mathrm{x})}{{\mathrm{r}}^2}=\frac{\alpha {\mathrm{r}}^2}{4{\epsilon }_0}$