A circular capillary has a diameter of \(10 \mu \mathrm{m}\) and a length of \(3 \mathrm{~cm}\). The surface carries a zeta potential of \(-0.5 \mathrm{~V}\). The flowing fluid is an aqueous solution of \(0.01 \mathrm{M} \mathrm{CaSO}_{4}\), and the viscosity is \(0.001 \mathrm{~Pa} \cdot \mathrm{s}\) at the specified temperature.

Find the volumetric flow rate. Also compute the pressure gradient that would need to be applied to create the same flow if no electric field were applied.