Why does the speed of the magnet matter in a coil?

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Discussion Overview

The discussion centers around the relationship between the speed of a magnet moving through a coil and the induced voltage (emf) according to Faraday's law of electromagnetic induction. Participants explore the implications of magnet speed on induced emf, particularly in scenarios where the magnet is stationary versus moving.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants express confusion about why the speed of the magnet affects the induced voltage when the magnetic field is constant and the magnetic flux appears to be the same.
  • Questions are raised regarding the amount of emf induced when the magnet is stationary inside the coil, with some suggesting it would be zero since there is no movement of electrons.
  • One participant suggests that the motion of the magnet generates the emf, stating that faster motion results in greater emf due to more flux lines cutting through the coil in a unit of time.
  • Another participant agrees that if the magnet is stationary relative to the coil, no emf would be induced.

Areas of Agreement / Disagreement

Participants generally agree that if the magnet is stationary, no emf is induced. However, there is ongoing confusion and exploration regarding the relationship between the speed of the magnet and the induced emf, indicating that multiple views and uncertainties remain.

Contextual Notes

The discussion does not resolve the underlying reasons for the relationship between magnet speed and induced emf, leaving some assumptions and conditions unaddressed.

alfab
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I am currently studying Faraday's law and electromagnets and in class we were told that if you had a coil and say a bar magnet was passed through it the faster the magnetic field was applied to the coil the greater the induced voltage or emf would be. I do not understand why the speed would matter if the magnetic field was constant from the bar magnet and the magnetic flux would be the same. Why would it be greater if the magnet was moving faster?
 
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alfab said:
I am currently studying Faraday's law and electromagnets and in class we were told that if you had a coil and say a bar magnet was passed through it the faster the magnetic field was applied to the coil the greater the induced voltage or emf would be. I do not understand why the speed would matter if the magnetic field was constant from the bar magnet and the magnetic flux would be the same. Why would it be greater if the magnet was moving faster?
How much emf is induced if the magnet is just placed inside the coil and left stationary?
 
phinds said:
How much emf is induced if the magnet is just placed inside the coil and left stationary?
it would be 0 correct? because if the magnet is not moving at all the electrons in the coil are not moving
 
alfab said:
it would be 0 correct? because if the magnet is not moving at all the electrons in the coil are not moving
Yes, exactly. I was trying to lead you to the understanding on your own that jedishrfu has now provided to you.
 
okay thank you this makes a lot more sense now
 

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