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प्रश्न
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.
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उत्तर
The working principle of the transformer is the mutual induction. The magnetic flux linked with the primary winding of the transformer must change, to produce an induced emf in the secondary coil.
Transformers cannot work on DC voltages. If a DC supply is given to the primary coil of a transformer, it produces a steady magnetic flux. So, no emf will be induced in the secondary coil.
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संबंधित प्रश्न
Derive an expression for ratio of e.m.f.s and currents in terms of number of turns in primary and secondary coil.
The primary coil of an ideal step-up transformer has 100 turns and the transformation ratio is also 100. The input voltage and power are 220 V and 1100 W, respectively. Calculate the
(a) number of turns in secondary
(b) current in the primary
(c) a voltage across secondary
(d) current in secondary
(e) power in secondary
The input and output voltage of a transformer are 220 V and 44 V respectively. Find: the turns ratio.
What is the turns ratio i.e., transformer ratio, ns: np, in an ideal transformer which in-creases ac voltage from 220 V to 33000 V?
State the factors on which the frequency of the alternating e.m.f. depends.
Applying e.m. f to primary coil is 210 V. If the number of turns in primary coil is 200 turns and that of in secondary coil is 20 turns, then find out the output voltage. Name the type of transformer.
Distinguish between Step up and Step Down Transformer.
Electrical energy is transmitted over large distances at high alternating voltages. Which of the following statements is (are) correct?
- For a given power level, there is a lower current.
- Lower current implies less power loss.
- Transmission lines can be made thinner.
- It is easy to reduce the voltage at the receiving end using step-down transformers.
Two coils P and Q are kept near each other. When no current flows through coil P and current increase in coil Q at the rate 10A/s, the emf in coil P is 15mV. When coil Q carries no current and current of 1. 8A flows through coil P, the magnetic flux linked with the coil Q is ______.
An iron rod of 0.2 cm2 cross-sectional area is subjected to a magnetising field of 1200 Am-1. If the susceptibility of iron is 599, then the magnetic flux produced is ______.
