Electrical energy is transmitted over large distances at high alternating voltages. Which of the following statements is (are) correct?
(a) For a given power level, there is a lower current.
(b) Lower current implies less power loss.
(c) Transmission lines can be made thinner.
(d) It is easy to reduce the voltage at the receiving end using step-down transformers.
Choose the correct options:
1. (a), (b), (c) 2. (a), (b), (d)
3. (b), (c), (d) 4. (c), (d)
Subtopic:  Transformer |
 61%
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A transformer is used to light a 100 W and 110 V lamp from a 220 V main. If the main current is 0.5 A, the efficiency of the transformer is approximately:
1. 30%
2. 50%
3. 90%
4. 10%

Subtopic:  Transformer |
 74%
From NCERT
AIPMT - 2007
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A transformer operating at a primary voltage of 8 kV and secondary voltage of 160 V serves a load of 80 kW. Assuming the transformer to be ideal with purely resistive load and working on unity power factor, the loads in the primary and secondary circuit would be:
1. 800 Ω and 1.06 Ω 2. 10 Ω and 500 Ω
3. 800 Ω and 0.32 Ω 4. 1.06 Ω and 500 Ω
Subtopic:  Transformer |
 81%
From NCERT
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A transformer has an efficiency of 80%. It works at 40 kW and 100 V. If the secondary voltage is 240 V, the current in the secondary coil is nearly:
1. 40 A
2. 133.3 A
3. 86.7 A
4. 112 A
Subtopic:  Transformer |
 88%
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A transformer with 8:1 turns ratio has 50 Hz, 100 V input. The frequency of the output is: 
1. 40 Hz
2. 50 Hz
3. 400 Hz
4. 500 Hz
Subtopic:  Transformer |
 77%
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In an ideal transformer, the number of turns in primary and secondary coils are 500 and 2000 respectively. If the current in the primary coil is 48 A, then the current in the secondary coil will be:
1. 12 A
2. 24 A
3. 48 A
4. 144 A
Subtopic:  Transformer |
 88%
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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?
1. 2 A
2. 4 A
3. 0.2 A
4. 0.4 A
Subtopic:  Transformer |
 69%
From NCERT
NEET - 2021
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An ideal transformer has 100 turns in the primary coil and carries a 5 A current. To achieve a 1600 V output with a 2 kW power output, the number of turns in the secondary coil must be:
1. 100
2. 200
3. 300
4. 400 
Subtopic:  Transformer |
 84%
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12 V,60 W lamp is connected to the secondary of a step-down transformer, whose primary is connected to AC mains of 220 V. Assuming the transformer to be ideal, what is the current in the primary winding?
1. 0.37 A
2. 0.27 A
3. 2.7 A
4. 3.7 A
Subtopic:  Transformer |
 72%
From NCERT
NEET - 2023
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A power transmission line feeds input power at 2300 V to a step-down transformer with its primary windings having 4000 turns. What should be the number of turns in the secondary in order to get output power at 230 V?
1. 200
2. 250
3. 350
4. 400

Subtopic:  Transformer |
 79%
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