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प्रश्न
Distinguish between Step up and Step Down Transformer.
उत्तर
| No. | Step-up transformer | Step-down transformer |
| i. | The number of turns in its secondary is more than that in its primary (NS > NP). | The number of turns in primary is greater than secondary (NP > NS). |
| ii. | The alternating voltage across the ends of its secondary is more than that across its primary i.e., eS > eP | The alternating voltage across the ends of the primary is more than that across its secondary i.e., eP > eS |
| iii. | Transformer ratio K > 1. | Transformer ratio K < 1. |
| iv. | Primary coil made of thick wire. | Secondary coil made of thick wire. |
| v. | The secondary coil is made of thin wire. | The primary coil is made of thin wire. |
| vi. | Current through secondary is less than primary. | Current through primary is less than secondary. |
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संबंधित प्रश्न
State the principle on which transformer works.
Derive an expression for e.m.f. and current in terms of turns ratio
State the principle of the step-down transformer and its working.
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State the principle of transformer working with the help of a diagram
Mention various energy losses in transformer device
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State two ways through which the strength of an electromagnet can be increased.
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(b) Name and state the law which explains the above observations.
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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.
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State whether true or false. If false, correct the statement.
A transformer can step up direct current.
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Give the advantage of AC in long distance power transmission with an illustration.
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- Voltage transformation ratio and
- Current in the primary
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Assertion: A transfonner cannot work on D.C. supply.
Reason: D.C. changes neither in magnitude nor in direction.
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.
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The value of voltage across the secondary coil is ______.
Define a Transformer.
The primary winding of a transformer has 100 turns and its secondary winding has 200 turns. The primary is connected to an a.c supply of 120 V and the current flowing in its is 10 A. The voltage and the current in the secondary are ______.
For an LCR circuit, the power transferred from the driving source to the driven oscillator is P = I2Z cos φ.
- Here, the power factor cos φ ≥ 0, P ≥ 0.
- The driving force can give no energy to the oscillator (P = 0) in some cases.
- The driving force cannot syphon out (P < 0) the energy out of oscillator.
- The driving force can take away energy out of the oscillator.
The line that draws power supply to your house from street has ______.
- zero average current.
- 220 V average voltage.
- voltage and current out of phase by 90°.
- voltage and current possibly differing in phase `phi` such that `|phi| < pi/2`.
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For what purpose are the transformers used?
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