Advertisements
Advertisements
प्रश्न
What is a transformer? On what principle does it work?
Advertisements
उत्तर
A transformer is device by which the amplitude of an alternating e.m.f. can be increased or decreased.
APPEARS IN
संबंधित प्रश्न
Derive an expression for e.m.f. and current in terms of turns ratio
Explain why an induced current must flow in such a direction so as to oppose the change producing it.
Explain the significance of Lenz’s law to show the conservation of energy in electromagnetic induction.
An ideal transformer has 100 turns in the primary and 250 turns in the secondary. The peak value of the AC is 28 V. The rms secondary voltage is nearest to ______
What are step-up and step-down transformers?
Give the advantage of AC in long distance power transmission with an illustration.
Assertion: A transfonner cannot work on D.C. supply.
Reason: D.C. changes neither in magnitude nor in direction.
Read the following paragraph and answer the question:
Long distance power transmissions
The large-scale transmission and distribution of electrical energy over long distances is done with the use of transformers. The voltage output of the generator is stepped up. It is then transmitted over long distances to an area sub-station near the consumers. There the voltage is stepped down. It is further stepped down at distributing sub-stations and utility poles before a power supply of 240 V reaches our homes.
We need to step-up the voltage for power transmission, so that ______.
In a transformer, number of turns in the primary coil are 140 and that in the secondary coil are 280. If current in primary coil is 4 A, then that in the secondary coil is ______.
Efficiency of transformer is the ratio of ______.
