Suppose the capacitor in Figure 26.9 has a plate separation distance \(d\) and the plates carry charges \(+q\) and \(-q\) when the capacitor is connected to a battery that maintains a potential difference \(V_{\text {batt }}\) between its terminals. If a metal slab of thickness \(d / 2\) is inserted midway between the plates while the battery remains connected, what happens to

(a) the magnitude of the electric field between the plates and 

\((b)\) the quantity of charge on the plates?