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प्रश्न
Describe briefly and two energy losses, giving the reasons for their occurrence in actual transformers ?
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उत्तर
Energy losses occur in transformers:
(i) Flux leakage: Not all of the flux due to primary coil passes through the secondary due to poor design of the core or the air gaps in the core.
(ii) Eddy currents: The alternating magnetic flux induces eddy currents in the iron core and causes heating.
संबंधित प्रश्न
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?
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(i) Draw a clear labelled diagram of an electric bell.
(ii) Explain in brief, its working.
(iii) What material is used for the core of an electric bell? State the reason.
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.
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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.
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- Here, the power factor cos φ ≥ 0, P ≥ 0.
- The driving force can give no energy to the oscillator (P = 0) in some cases.
- The driving force cannot syphon out (P < 0) the energy out of oscillator.
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