1) A solid sphere of radius R carries a uniform volume charge density $\rho$. The magnitude of the electric field inside the sphere at a distance r from the centre is A) $\frac{r\rho}{3\epsilon_{0}}$ B) $\frac{R\rho}{3\epsilon_{0}}$ C) $\frac{R^{3}\rho}{2\epsilon_{0}}$ D) $\frac{R^{3}\rho}{3\epsilon_{0}}$ Answer: Option AExplanation:$E= \frac{1}{4\pi\epsilon_{0}}\frac{qr}{R^{3}}=\frac{q}{\frac{4}{3}\pi R^{3}}\times\frac{r}{3\epsilon_{0}}=\frac{\rho\times r}{3\epsilon_{0}}$
