Questions in emi

Select	Question
	The induction coil works on the principle of
	A transformer with efficiency 80% works at 4 kW and 100 V. If the secondary voltage is 200 V, then the primary and secondary currents are respectively
	In a step up transformer, if ratio of turns of primary to secondary is 1 : 10 and primary voltage is 230 V. If the load current is 2A, then the current in primary is
	If a coil made of conducting wires is rotated between poles pieces of the permanent magnet. The motion will generate a current and this device is called
	A step-down transformer is used on a 1000 V line to deliver 20 A at 120 V at the secondary coil. If the efficiency of the transformer is 80% the current drawn from the line is .