The density of fluid does not affect the working of an electromagnetic flow meter, which uses Faraday's Law of Electromagnetic Induction to measure flow rate. Orifice meters use a central hole to generate pressure difference and measure flow quantity, while rotameters measure flow rate by allowing the cross-sectional area of fluid to vary. Nozzle meters consist of a short nozzle held between two pipe flanges to measure flow rate with a discharge coefficient value between 0.93 and 0.98.
