An atom has a positively charge point nucleus of charge Ze surrounded by a uniform density of negative charge upto a radius R. The atom is taken as neutral. The electric field at a distance r<R from the nucleus is given by-

$\frac{Ze}{4πε_0}\left[\frac{1}{r^3}\right]$ $\frac{Ze}{4πε_0}\left[\frac{1}{r^2}-\frac{r}{R^3}\right]$ $\frac{Ze^2}{4πε_0}\left[\frac{1}{r^3}-\frac{1}{R^3}\right]$ $\frac{Ze}{4πε_0}\left[\frac{1}{r^4}\right]$

$\frac{Ze}{4πε_0}\left[\frac{1}{r^2}-\frac{r}{R^3}\right]$

The correct answer is Option (2) → $\frac{Ze}{4πε_0}\left[\frac{1}{r^2}-\frac{r}{R^3}\right]$