A current of 5 A flows in the winding of an electric motor, the resistance of the winding being 100Ω. Determine (a) the p.d. across the winding, and (b) the power dissipated by the coil.

Calculate the power dissipated when a current of 4 mA flows through a resistance of 5 kΩ

A wire carries a current of 0.10 µA. The potential difference across the wire is 10 mV.How much energy is dissipated by the wire in a time of 10 s?A 1.0 pJ B 10 pJ C 1.0 nJ D 10 nJ

Current of 7.5 A flows through a non-inductive resistance in series with a choke coil when connected to supply of 230 V, 50 Hz. If the voltage across the resistance is 110 V and across the coil 180 V. Calculate (i) resistance, reactance and impedance of the choke coil; (ii) total resistance and imped- ance of the circuit; (iii) power absorbed by the coil; (iv) total power drawn by the circuit; and (v) power factor of the whole circuit.[Ans. 5.1 2, 23.45 ; 24 2, 19.77 2; 30.67 0. 286.9 W; 1112 W; 0.645 lagging]

A current of 2 A is passed through a coil of resistance 75 ohm for 2 minutes. (a) How much heat energy is produced ? (b) How much charge is passed through the resistance?

A coil of resistance 10Ω and inductance 140mH is connected in parallel with a 260Ωresistor across a 230V, 50Hz supply. Calculate the following(i) Current in the coil (3 Marks)(ii) Supply current (3 Marks)(iii) Circuit impedance (3 Marks)(iv) Power factor (3 Marks)(v) Power consumed