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प्रश्न
Name three losses of energy in a transformer. How are they minimized?
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उत्तर
(i) Heat losses in the windings of transformer. They are minimized by taking a thicker wire in the primary coil than in the secondary coil in a step-up transformer, whereas a thicker wire in secondary coil than in primary coil in a step-down transformer.
(ii) Hysteresis losses in the core of transformer. They are minimized by using soft iron core.
(iii) Eddy current losses in the core of transformer. They are minimized by taking the core laminated instead of taking it as one solid piece.
संबंधित प्रश्न
State two ways through which the strength of an electromagnet can be increased.
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?
What is the ideal 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.
For an ideal step-down transformer, the quantity which is constant for both the coils is ______.
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?
A transformer is essentially an a.c. device. It cannot work on d.c. It changes alternating voltages or currents. It does not affect the frequency of a.c. It is based on the phenomenon of mutual induction. A transformer essentially consists of two coils of insulated copper wire having different numbers of turns and wound on the same soft iron core.
The number of turns in the primary and secondary coils of an ideal transformer is 2000 and 50 respectively. The primary coil is connected to a main supply of 120 V and secondary coil is connected to a bulb of resistance 0.6 Ω.
Power in primary coil is ______.
In a transformer, number of turns in the primary coil are 140 and that in the secondary coil are 280. If current in primary coil is 4 A, then that in the secondary coil is ______.
Derive the equation for a transformer.
In an ideal transformer, the turns ratio is `N_p/N_s = 1/2`. The ratio Vs : Vp is equal to (the symbols carry their usual meaning):
