A uniformly charged disc of radius \(R\) having surface charge density \(\sigma\) is placed in the \(x y\) plane with it…

\(E=\frac{\sigma}{2 \varepsilon_0}\left(1+\frac{Z}{\left(Z^2+R^2\right)^{1 / 2}}\right)\)

\(E=\frac{\sigma}{2 \varepsilon_0}\left(1-\frac{Z}{\left(Z^2+R^2\right)^{1 / 2}}\right)\)

\(E=\frac{2 \varepsilon_0}{\sigma}\left(\frac{1}{\left(Z^2+R^2\right)^{1 / 2}}+Z\right)\)

\(E=\frac{\sigma}{2 \varepsilon_0}\left(\frac{1}{\left(Z^2+R^2\right)}+\frac{1}{Z^2}\right)\)