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प्रश्न
Explain the construction and working of the transformer.
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उत्तर
Construction: It consists of two coils of primary and secondary coils insulated from each other and wound on a soft iron core as shown in fig. (a). Input is applied across the primary coil, and output is taken across the secondary coil.
Notations:
P1, P2: Primary coil
S1, S2: Secondary coil
There are two types of transformers:
- Step-up transformer: In this, the number of turns in the primary coil is less than the number of turns in the secondary coil. The primary coil is made up of thick wire, and the secondary coil is made up of thin wire.
- Step-down transformer: Here the number of turns in the primary coil is greater than that in the secondary coil. The secondary coil is made up of thick wire, and the primary coil is of thin wire.
Working: When an AC voltage is applied to the primary coil, the current through the coil goes on changing. Hence the magnetic flux through the core also changes. As this changing magnetic flux is linked with both coils, an emf is induced in each coil. The amount of magnetic flux linked with the coil depends upon the number of turns of the coil.
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संबंधित प्रश्न
Draw a labeled diagram of a step-down transformer.
Derive an expression for e.m.f. and current in terms of turns ratio
Express the turn ratio in terms of voltages.
Find the ratio of primary and secondary currents in terms of turn ratio in an ideal transformer.
Mention various energy losses in transformer device
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?
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Name the phenomenon ?
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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?
Name two kind of energy loss in a transformer. How is it minimized?
The primary coil of a transformed has 800 urns and the secondary coil has 8 turns. It is connected to a 220 V a.c. supply. What will be the output voltage?
Mention the two characteristic properties of the material suitable for making core of a transformer.
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Name three losses of energy in a transformer. How are they minimized?
Draw a labelled diagram to show the various parts of a step-up transformer and step down transformer.
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Mention the various energy losses in a transformer.
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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.
Which of the following statement is true?
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 ______.
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The value of current in the bulb is ______.
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- The driving force cannot syphon out (P < 0) the energy out of oscillator.
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The primary coil of a transformer has 60 turns whereas its secondary coil has 3000 turns.
If a 220 V ac voltage is applied to the primary coil, how much emf is induced in the secondary coil?
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What type of transformer is used in a mobile phone charger?
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