Loops and Magnets, Lenz's Law

In summary, the figures show two situations where a current may be induced in a loop according to Faraday's Law and Lenz' Law. In figure 2, the current flows clockwise as the magnetic field gets weaker and counterclockwise as it gets stronger, indicating that options C and E are correct. In figure 1, the current flows counterclockwise as the magnet and loop get closer and clockwise as they move apart, indicating that options C, D, E, and F are all correct.
  • #1
K3nt70
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Homework Statement


The figures below show two different situations where a current may be induced in a loop according to Faraday's Law, with the direction given by Lenz' Law. The magnetic field is shown by the x's in Fig. 2. Select ALL correct answers (i.e. B, AC, BCD) for the current in the loop. (The compass directions are defined in the usual way.)

http://img517.imageshack.us/img517/9134/prob07lenzlaw1us4.gif
http://img67.imageshack.us/img67/2264/prob07lenzlaw2pi7.gif

A) fig2: Loop moving North, induced current `b'.
B) fig1: Magnet moving West, induced current `a'.
C) fig2: Loop moving South, no induced current.
D) fig1: Loop moving West, induced current `a'.
E) fig2: Loop moving East, induced current `b'.
F) fig1: Magnet moving East, induced current `a'.

In figure 2, the magnetic field is strongest on the left, weakest on the right. As the magnetic field gets weaker, the current will flow clockwise (b) as the magnetic field gets stronger the current travels counterclockwise (a). since the magnetic field is the same if you move up or down, this means that C and E are true. Using the same principle for figure 1, (as they get closer together, the current flows counterclockwise, as they move apart, the current flows clockwise. This means that CEF should be the answer... What am i missing?
 
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  • #2
any insight into this one?
 
  • #3
How do D & F differ? :wink:
 
  • #4
jeez, why didnt i see that?:P So you would put your money on CDEF? i only have one attempt left at the question
 
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  • #5
That's what I'd put.
 
  • #6
Correct! Thanks
 

1. What is a loop and how does it interact with magnets?

A loop is a closed path or circuit that allows electricity to flow through it. When a loop is placed near a magnet, it will experience a force due to the magnetic field produced by the magnet. This force can cause the loop to move or rotate, depending on the orientation of the loop and the magnet.

2. What is Lenz's Law and how does it relate to loops and magnets?

Lenz's Law is a basic law of electromagnetism that states that the direction of an induced current in a conductor will be such that it creates a magnetic field that opposes the change in the magnetic field that caused it. In the context of loops and magnets, this means that when a magnet is moved towards or away from a loop, it will induce a current in the loop that creates a magnetic field that opposes the change in the magnet's field.

3. How can Lenz's Law be demonstrated with a simple experiment?

A simple demonstration of Lenz's Law can be done by taking a loop of wire and placing it near a bar magnet. As the magnet is moved towards the loop, the loop will experience a force and will begin to rotate. This is due to the induced current in the loop creating a magnetic field that opposes the change in the magnet's field. As the magnet is moved away from the loop, the direction of the induced current will reverse, causing the loop to rotate in the opposite direction.

4. Can Lenz's Law be applied to any type of magnet and loop setup?

Yes, Lenz's Law can be applied to any type of magnet and loop setup, as long as the loop is able to conduct electricity and the magnet produces a magnetic field. This law is a fundamental principle of electromagnetism and applies to all types of electromagnetic interactions.

5. What are some real-world applications of Lenz's Law?

Lenz's Law has many real-world applications, including in generators, motors, and transformers. In generators, Lenz's Law is used to convert mechanical energy into electrical energy. In motors, it is used to convert electrical energy into mechanical energy. In transformers, it is used to change the voltage of an alternating current. Lenz's Law is also used in electromagnetic braking systems, which use induced currents to slow down or stop moving objects.

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