Given Data Voltage Va = 200 v Armature Resistance Ra = 0.5Ω Armature Current Ia = 20 A Induced EMF = Ea = ? The Induced EMF of a DC machine working as a Motor is Ea = Va − IaRa Ea = 200 − 20 × 0.5 Ea = 190 V
Luminous flux measures the total radiant power reaching a surface, but without regard to surface position: the power might be concentrated on only part of the surface or spread evenly across it. Irradiance (Ee) or illuminance (Ev) is the density of incident radiant flux or luminous flux at a point on a surface and is defined as radiant flux or luminous flux per unit area, as given by E = dφ/dA where (dφ) is the radiant flux or luminous flux incident on an element dA of the surface containing the point. The unit of irradiance is Wm−2, and that of illuminance is lux
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
Galvanized steel conductors do not corrode, and possess high resistance. Hence such Wires are used in telecommunications circuits, earth wires, guard wire, stray wire, etc.
EXAMIANS