No Induced Current in a Moving Magnet?

In summary, the conversation discusses the scenario in which a current will not be induced in a conducting loop. Through the process of elimination and understanding of the basics of inducing a current, it can be determined that the correct answer is e: a magnet rotating in front of a conducting loop of wire. This is because in all other scenarios, there is a change in the magnetic flux, while in this scenario, there is no change. The conversation also highlights the importance of understanding the right hand rules for determining the direction of induced current.
  • #1
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Homework Statement


In which of the following will a current NOT be induced in the conducting loop?

a. Magnet moving toward upright conducting loop of wire
b. Magnet moving away from an upright conducting loop of wire
c. Magnet moving toward a horizontal conducting loop of wire
d. Conducting loop of wire rotating in front of magnet
e. Magnet rotating in front of conducting loop of wire

2. The attempt at a solution
I eliminated d because the loop is being rotated and that should trigger induced current, right?
a, b, and c seem like they would have induced current because the loop is moved into or out of the magnetic field, with either the magnet moving.

So I know that when the loop is rotated, there is induced current, but is that the same for a rotated magnet? If a rotated magnet does not trigger induced current, then would e be the correct answer?
 
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  • #2
You need to go back to basics - how is a current induced in a loop: what has to happen as far as the magnetic field inside the loop is concerned?

I also think you need to take a closer look at what difference it makes if the loop is "upright" or "horizontal" for the purpose of this question.
 
  • #3
Remember that induced currents are caused by a changing magnetic flux. Knowing that, do any of the solutions present a situation where there isn't a change in flux or there is no flux at all?
 
  • #4
The magnetic field must either increase or decrease. If there is no change, there will be no current.

Okay I can see where this is getting at.. I think I need to review my right hand rules as well while I'm at it... Thank you!
 
  • #5



I can confirm that option e, "Magnet rotating in front of conducting loop of wire," will not induce a current in the conducting loop. This is because in order for a current to be induced, there must be a changing magnetic field passing through the loop. In this case, both the magnet and the loop are rotating together, so there is no change in the magnetic field. Therefore, there will be no induced current in the conducting loop.

On the other hand, options a, b, and c will all induce a current in the conducting loop because the magnet is either moving towards or away from the loop, causing a change in the magnetic field. This change in the magnetic field induces a current in the conducting loop, according to Faraday's Law of Induction.

Option d may also induce a current in the conducting loop, depending on the orientation of the magnet and the direction of rotation of the loop. If the magnetic field lines are passing through the loop as it rotates, there will be a change in the magnetic field and thus, an induced current.

In summary, a current will not be induced in a conducting loop when a rotating magnet is placed in front of it, but it may be induced if the loop is rotating in front of a stationary magnet (option d). Options a, b, and c will all induce a current due to the changing magnetic field caused by the moving magnet.
 

1. What is the concept of "No Induced Current in a Moving Magnet?"

The concept of "No Induced Current in a Moving Magnet" refers to the phenomenon where a moving magnet does not generate an electric current in a stationary conductor. This is a fundamental principle in electromagnetism known as Faraday's law of induction.

2. Why does a moving magnet not induce a current in a stationary conductor?

This is due to the fact that the movement of the magnet generates a changing magnetic field, which in turn induces an electric field. However, since the conductor is stationary, the electrons are not free to move and therefore no current is generated.

3. Can a current be induced in a stationary magnet?

No, a current cannot be induced in a stationary magnet. This is because a changing magnetic field is required to induce a current, and a stationary magnet does not produce a changing magnetic field.

4. Does the speed of the moving magnet affect the induced current?

Yes, the speed of the moving magnet does affect the induced current. According to Faraday's law, the faster the magnet moves, the stronger the induced current will be.

5. What are some real-world applications of "No Induced Current in a Moving Magnet?"

This principle is important in various technologies, such as electric generators, transformers, and induction cooktops. It is also utilized in wireless charging and some forms of transportation, such as maglev trains.

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