few electronic appliances like fan or light. An inverter has inbuilt step-up transformer which converts V AC to V AC. The primary coil has turns and the inverter delivers mA to the external circuit. Find the number of turns in the secondary and the primary current.
Solution V p = V; V s = V I s = 50mA; N p = turns K Illustration: An electric power of MW is transmitted to a place through transmission lines of total resistance R = Ω, at two different voltages. One is lower voltage ( kV) and the other is higher ( kV). Let us now calculate and compare power losses in these two cases. Case (i): P = MW; R = Ω; V = kV Power, P VI ∴ Current, I Power loss = Heat produced = I R = ( ) × W % of power loss = % % = % Case (ii): P = MW; R = Ω; V = kV ∴ Current, I Power loss = I R = ( ) × W % of power loss = % % = .
% Thus it is clear that when an electric power is transmitted at higher voltage, the power loss is reduced to a large extent. 12th - 12th - - - - - Unit ELECTROMAGNETIC INDUCTION AND ALTERNATING CURRENT