In a capillary flow experiment $($Poiseuille flow$),$ the pressure drop across the capillary corresponding to a steady flow rate of $120$ ml$/$minute is $20$ kPa. The diameter of the capillary tube is $1$ cm$.$ In a second proposed experiment using the same fluid, a tube $0\mathrm{.}5$ cm in diameter is to be employed. Tube lengths are identical in both cases. The material characteristics of the two tubes are also the same. What would be the flow rate in the second experiment if the pressure drop is maintained at $20$ kPa?