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प्रश्न
Mention the two characteristic properties of the material suitable for making core of a transformer.
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उत्तर
Since due to iron core we have two types of losses,
1. Iron lossi.e. energy loss in the form of heat due to the induced eddy current that can be minimized by using thin laminated core.
2. Hysteresis loss due to alternately passing a current in the coil to magnetize and demagnetize the iron core. This can be reduced by using a special alloy of iron core with silicon.
So material with less iron loss and less hysteresis loss is used for making core of transformer.
संबंधित प्रश्न
State the principle of transformer working with the help of a diagram
The teachers of Geeta’s school took the students on a study trip to a power generating station, located nearly 200 km away from the city. The teacher explained that electrical energy is transmitted over such a long distance to their city, in the form of alternating current (ac) raised to a high voltage. At the receiving end in the city, the voltage is reduced to operate the devices. As a result, the power loss is reduced. Geeta listened to the teacher and asked questions about how the ac is converted to a higher or lower voltage.
1) Name the device used to change the alternating voltage to a higher or lower value. State one cause for power dissipation in this device.
2) Explain with an example, how power loss is reduced if the energy is transmitted over long distances as an alternating current rather than a direct current.
3) Write two values each shown by the teachers and Geeta.
On which type of current do transformers work?
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.
Complete the following sentence :
……… energy is converted into …………energy by an electric motor.
A transformer is used to step up an alternating emf of 200V to 440V. If the primary coil has 1000 turns, calculate the number of turns in the secondary coil.
A 100% efficient transformer has 100 turns in the primary and 50 turns in its secondary coil. If the current in the secondary coil is 6 A, then the current in the primary coil is ______.
The magnetic flux through a coil perpendicular to its plane is varying according to the relation Φ = (5t3 + 4t2 + 2t - 5) Weber. If the resistant of the coil is 5 ohm, then the induced current through the coil at t = 2 sec will be ______.
Derive the equation for a transformer.
