$\begin {array} {1 1} (a)\;\large\frac{13 q E_0}{2B_0} & \quad (b)\;\large\frac{8B_0}{ q E_0} \\ (c)\;\large\frac{25}{2 q E_0} & \quad (d)\;\large\frac{8q}{B_0} \end {array}$