The reluctance of any part of a magnetic circuit may be defined as the ratio of the drop in magnetomotive force to the flux produced in that part of the circuit. It is measured in ampere-turns/Weber and is denoted by S. Reluctance = m.m.f ⁄ flux
P = ρ QHg is the water power equation. Where H = heead = meter g = gravity =m/s2 ρ =density = (kg/m3) P = power = watt = N-m/sec Q = water flow rate = m3/sec