MCQ Detailed View

The correct answer is Mutual induction. A transformer is an electrical device used to increase or decrease alternating current (AC) voltage in circuits. It works on the principle of mutual induction, which occurs when a changing current in one coil induces an electromotive force (EMF) in a nearby coil.

A basic transformer consists of two coils—the primary coil connected to the input voltage and the secondary coil connected to the output. These coils are wound around a magnetic core, which helps transfer magnetic flux efficiently. When AC flows through the primary coil, it creates a time-varying magnetic field in the core. According to the principle of mutual induction, this changing magnetic field induces a voltage in the secondary coil.

The voltage induced in the secondary coil depends on the ratio of the number of turns in the secondary coil to the number of turns in the primary coil, called the turns ratio. This allows the transformer to either step up (increase) or step down (decrease) voltage, making it essential for power transmission, household appliances, and electronics.

It is important to note that:

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  Self-induction occurs in a single coil and is used in inductors, not transformers.

  
  


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  Generators convert mechanical energy into electrical energy.

  
  


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  Inverters convert DC to AC.

  
  

Mutual induction is a fundamental concept in electromagnetism and forms the working principle of nearly all transformers, which are critical in electric power distribution worldwide. Without this principle, we could not efficiently transmit electricity over long distances, as high voltage is needed to reduce energy loss in power lines.

🔑 Key Facts:

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  Transformer = device to step up or step down AC voltage.

  
  


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  Works on mutual induction between primary and secondary coils.

  
  


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  Dependent on the turns ratio of coils.

  
  


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  Uses magnetic core to efficiently transfer flux.

  
  


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  Essential for power transmission, electronics, and appliances.

  
  

👉 Final Answer: A transformer works on the principle of Mutual induction.