The back e.m.f. of a d.c. motor delivering 5 kW of mechanical power is 200 v, when operating on a 220 V line. Determine the armatre current and the motor resistsance.

An electric motor takes 5 A form a 220 V line. Determine the power of the motor and the energy consumed in 2 h.

An electric kettle consumes 1kW of electic power when operated at 220 V. A fuse wire of the what rating must be used for it?

An electric motor takes 5A form a 220 V line. Determine the power of the motor and the energy consumed in 2 hours

A small d.c. motor operating at 200 V draws a current of 5.0 A at its full speed of 3,000 r.p.m. The resistance of the armature of the motor is 8.5 Omega. Determine the back e.m.f. of the motor. Obtain the power input, power output (mechanical) and the efficiency of the motor.

An electric motor runs on a dc source of emf E and internal resistance r. Show that the power output of the source, is maximum when the current drawn by the motor is (E)/(2r) .

A step-up transformer operates on a 200 volt line and supplies a load of 2 ampere. The ratio of primary and secondary windings is 1:5. Determine the secondary voltge, primary current and power output. Assume efficiency to be 100%.

An electric motor takes 5A from a 220 V line. Calculate the energy consumed by it in 30 seconds.