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Created page with "==Key Stage 5== ===Meaning=== Back emf is the electromotive force (emf) induced in the spinning coil of an [..."
==Key Stage 5==
===Meaning===
[[Back EMF|Back emf]] is the [[Electromotive Force|electromotive force (emf)]] [[Electromagnetic Induction|induced]] in the spinning coil of an [[Motor|electric motor]] or in any coil where the [[Electrical Current|current]] is changing, such as in the [[Primary Coil|primary coil]] of a [[Electrical Transformer|transformer]]. This [[Back EMF|back emf]] acts against the change of applied [[Potential Difference|potential difference (pd)]].
===About Back emf===
*Occurs due to [[Lenz's Law|Lenz's Law]], which states that the direction of the [[Electromagnetic *Induction|induced]] [[Electromotive Force|emf]] is such that it opposes the change causing it.
*In an [[Motor|electric motor]], back [[Electromotive Force|emf]] increases with the [[speed]] of the [[motor]].
*It limits the current flowing through the motor as the [[speed]] increases.
*In [[Electrical Transformers|transformers]], [[Back EMF|back emf]] is [[Electromagnetic *Induction|induced]] in the [[Primary Coil|primary coil]] when the [[Electrical Current|current]] in the [[Secondary Coil|secondary coil]] changes.
*[[Back EMF|Back emf]] is crucial for the functioning of devices like [[motor]]s and [[Electrical Transformer|transformers]] by preventing excessive currents.
*It is a key factor in the design and operation of [[Alternating Current|AC]] and [[D.C. Motor|DC motors]].
===Examples**
*When an [[Motor|electric motor]] starts, the [[Back EMF|back emf]] is initially zero, allowing maximum [[Electrical Current|current]].
*[[Back EMF|Back emf]] in [[Electrical Transformer|transformers]] helps regulate the [[Electrical Current|current]] and [[Potential Difference|voltage]] during operation.
===Meaning===
[[Back EMF|Back emf]] is the [[Electromotive Force|electromotive force (emf)]] [[Electromagnetic Induction|induced]] in the spinning coil of an [[Motor|electric motor]] or in any coil where the [[Electrical Current|current]] is changing, such as in the [[Primary Coil|primary coil]] of a [[Electrical Transformer|transformer]]. This [[Back EMF|back emf]] acts against the change of applied [[Potential Difference|potential difference (pd)]].
===About Back emf===
*Occurs due to [[Lenz's Law|Lenz's Law]], which states that the direction of the [[Electromagnetic *Induction|induced]] [[Electromotive Force|emf]] is such that it opposes the change causing it.
*In an [[Motor|electric motor]], back [[Electromotive Force|emf]] increases with the [[speed]] of the [[motor]].
*It limits the current flowing through the motor as the [[speed]] increases.
*In [[Electrical Transformers|transformers]], [[Back EMF|back emf]] is [[Electromagnetic *Induction|induced]] in the [[Primary Coil|primary coil]] when the [[Electrical Current|current]] in the [[Secondary Coil|secondary coil]] changes.
*[[Back EMF|Back emf]] is crucial for the functioning of devices like [[motor]]s and [[Electrical Transformer|transformers]] by preventing excessive currents.
*It is a key factor in the design and operation of [[Alternating Current|AC]] and [[D.C. Motor|DC motors]].
===Examples**
*When an [[Motor|electric motor]] starts, the [[Back EMF|back emf]] is initially zero, allowing maximum [[Electrical Current|current]].
*[[Back EMF|Back emf]] in [[Electrical Transformer|transformers]] helps regulate the [[Electrical Current|current]] and [[Potential Difference|voltage]] during operation.