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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 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 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.
State two ways through which the strength of an electromagnet can be increased.
Draw a labelled diagram to show the various parts of a step-up transformer and step down transformer.
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.
Devices which is used to convert high alternating current to low alternating current is ______.
What are step-up and step-down transformers?
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.
A power transmission line feeds input power at 2300 V to a step down transformer with its primary windings having 4000 turns. The number of turns in the secondary in order to get output power at 230 V are ______.
An iron rod is placed parallel to magnetic field of intensity 2000 Am-1. The magnetic flux through the rod is 6 × 10−4 Wb and its cross-sectional area is 3 cm2. The magnetic permeability of the rod in Wb A-1m-1 is ______.
A step down transformer connected to an ac mains supply of 220 V is made to operate at 11 V, 44 W lamp. Ignoring power losses in the transformer, what is the current in the primary circuit?
