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प्रश्न
State the principle of a step-up transformer. Explain, with the help of a labeled diagram, its working ?
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उत्तर
Transformer:
Principle: It is a device which converts high voltage AC into low voltage AC and vice-versa. It is based upon the principle of mutual induction. When alternating current is passed through a coil, an induced emf is set up in the neighbouring coil.
Working: When an alternating current is passed through the primary, the magnetic flux through the iron core changes, which does two things. It produces emf in the primary and an induced emf is also set up in the secondary. If we assume that the resistance of primary is negligible, then the back emf will be equal to the voltage applied to the primary.
`therefore V_1 = -N_1 (dphi)/(dt)`
and`,V_2 = -N_2 (dphi)/dt`
Where, N1 and N2 are number of turns in the primary and the secondary respectively and V1 and V2 are their voltages respectively
In a step-up transformer: N2 > N1, therefore, V2 > V1
संबंधित प्रश्न
State the principle on which transformer works.
How is the e.m.f. across primary and secondary coils of a transformer related with the number of turns of the coil in them?
The following diagram in Fig.10.42 shows a coil of several turns of copper wire connected to a sensitive centre zero galvanometer G near a magnet NS. The coil is free to move in the direction shown in the diagram.
(i) Describe the observation if the coil is rapidly moved.
(ii) How would the observation be altered if (a) the coil has twice as many turns (b the coil was made to move three times as fast?
State the principle of working of a transformer. Can a transformer be used to step up or step down a d.c. voltage? Justify your answer.
A transformer lowers e.m.f. 220 V to 12 volts. If the number of turns in primary are 8800, how many turns are in secondary coil?
Explain the construction of transformer.
A transformer having efficiency of 80% is working on 200 V and 6 kW power supply. If the current in the secondary coil is 6 A, the voltage across the secondary coil and the current in the primary coil respectively are ____________.
A transformer is used ______
Why is soft iron used in the core?
What drives current through the connected load and delivers AC output?
