Past exam of the MPhil in micro- and nanotechnology enterprise course of the University of Cambridge / 2019 / Paper 2 / Section A(iii) / 19 / i / Solution

Negligible rail resistance makes all left-hand groove ends equipotential and all right-hand ends equipotential. The $N$ equal hydraulic resistances therefore connect in parallel:Here $\Delta p=R_{\mathrm{chip}}Q$ uses the total inlet flow. The two blind rail ends carry no flow beyond their final grooves.