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प्रश्न
The adjacent diagram shows a coil would around a soft iron bar XY. (a) State the polarity at the end X and Y as the switch is pressed. (b) Suggest one way increasing the strength of electromagnet so formed.
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उत्तर
(a)X-north pole, Y –south pole. (b)By reducing resistance of circuit by mean of rheostat to increase current.
संबंधित प्रश्न
Mention various energy losses in transformer device
On which type of current do transformers work?
The secondary windings of a transformer in which the voltage is stepped down are usually made of thicker wire than the primary. Explain why.
State the underlying principle of a transformer. How is the large scale transmission of electric energy over long distances done with the use of transformers?
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?
Name the principle on which functioning of a transformer depends.
Why is the core of a transformer made of soft iron?
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.
The self-inductance of a closely wound coil of 200 turns is 10 mH. Determine the value of magnetic flux through the cross-section of the coil when the current passing through the coil is 4 mA.
How do the input and output powers in a transformer compare? State the assumption made.
