- 1(current)
Q. No.A transformer is used to light a \(100~\text{W}\) and \(110~\text{V}\) lamp from a \(220~\text{V}\) main. If the main current is \(0.5~\text{A}\), the efficiency of the transformer is approximately:
1. \(30\%\)
2. \(50\%\)
3. \(90\%\)
4. \(10\%\)
Subtopic: Â Transformer |
 73%
From NCERT
AIPMT - 2007
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NEET 2025 - Target Batch
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The primary has \(100\) turns with \(100\) V RMS applied to it while the secondary has a total number of \(20\) turns, with the connection \(C\) made at the centre. The current \(i\) flowing towards \(C\) has the (RMS) value:
| 1. | \(2\) A | 2. | \(2\sqrt2\) A |
| 3. | \(\sqrt2\) A | 4. | zero |
Subtopic: Â Transformer |
From NCERT
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The primary coil of a transformer, when connected to a \(10~\text{V}\text-\)DC battery, draws a current of \(1~\text{mA}.\) The number of turns in the primary and secondary coils are \(50\) and \(100,\) respectively. The voltage across the secondary coil and the current drawn by the circuit in the secondary are respectively:
| 1. | \(20~\text{V}\) and \(2.0~\text{mA}\) |
| 2. | \(10~\text{V}\) and \(0.5~\text{mA}\) |
| 3. | zero and therefore no current |
| 4. | \(20~\text{V}\) and \(0.5~\text{mA}\) |
Subtopic: Â Transformer |
From NCERT
NEET - 2013
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A \(12~\text{V},60~\text{W}\) lamp is connected to the secondary of a step-down transformer, whose primary is connected to AC mains of \(220~\text{V}\). Assuming the transformer to be ideal, what is the current in the primary winding?
1. \(0.37~\text{A}\)
2. \(0.27~\text{A}\)
3. \(2.7~\text{A}\)
4. \(3.7~\text{A}\)
1. \(0.37~\text{A}\)
2. \(0.27~\text{A}\)
3. \(2.7~\text{A}\)
4. \(3.7~\text{A}\)
Subtopic: Â Transformer |
 70%
From NCERT
NEET - 2023
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- 1(current)
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