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
As you can see from the below figure in load Z1 is connected with the only current coil. In Load Z2 both current from the current coil (CC) and voltage from voltage coil (PC) are present (Power = V × I). Hence the Wattmeter will read power consumed by Z2.
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