Consider a hollow charged shell of inner radius a and outer radius b. The volume charge density is \(\rho(r)=\frac{k}{r^{2}}\) (k is a constant) in the region a < r < b. The magnitude of the electric field produced at distance r > a is
1
\(\frac{k(b-a)}{\varepsilon_{0} r^{2}}\) for all r > a
2
\(\frac{k(b-a)}{\varepsilon_{0} r^{2}}\) for a < r < b and \(\frac{k b}{\varepsilon_{0} r^{2}}\) for r > b
3
\(\frac{k(r-a)}{\varepsilon_{0} r^{2}}\) for a < r < b and \(\frac{k(b-a)}{\varepsilon_{0} r^{2}}\) for r > b
4
\(\frac{k(r-a)}{\varepsilon_{0} a^{2}}\) for a < r M b and \(\frac{k(b-a)}{\varepsilon_{0} r^{2}}\) for r > b