Solenoid's effect on a nearby iron ring

  • Thread starter Thread starter serverxeon
  • Start date Start date
  • Tags Tags
    Iron Ring
Click For Summary
SUMMARY

The discussion centers on the interaction between a solenoid with an iron core and a nearby iron ring. When the switch is closed, a change in magnetic flux induces a current in the ring, causing it to swing away momentarily due to Lenz's Law. When the potential divider is quickly moved to position X, the ring swings towards the solenoid, but remains at rest when the divider is held at X. Oscillations occur when the divider is moved between positions X and Y at a frequency of 2Hz. The participants debate the attraction of the iron ring to the solenoid, emphasizing the role of induced currents and magnetic fields.

PREREQUISITES
  • Understanding of Lenz's Law
  • Knowledge of magnetic flux concepts
  • Familiarity with solenoids and their magnetic fields
  • Basic principles of electromagnetism
NEXT STEPS
  • Study the principles of electromagnetic induction in detail
  • Learn about the behavior of ferromagnetic materials in magnetic fields
  • Explore the effects of alternating current on solenoids
  • Investigate the dynamics of oscillating systems in electromagnetism
USEFUL FOR

Students of physics, educators teaching electromagnetism, and anyone interested in the practical applications of solenoids and magnetic fields.

serverxeon
Messages
100
Reaction score
0

Homework Statement


You have an iron ring, hung near a solenoid which has an iron core inserted within.
[PLAIN]http://img843.imageshack.us/img843/1623/imgsole.jpg

Below are the questions and answers my book provided. I highly suspect the reasoning and i seek PF members to evaluate how true it is.
---------------------------

a) What happens when the switch is closed?
Ans: There will be a change in the magnetic flux going through the ring, and according to lens law, a current will be induced such that the resulting magnetic field opposes the change.
Hence, the ring will swing away momentarily.

b) What happens when the potential divider is brought to X quickly?
Ans: There will be a change in the magnetic flux going through the ring, hence, the ring will swing towards the solenoid momentarily

c) What happens when the potential divider remains at X?
Ans: The ring will remain at rest (ie. at equilibrium position)

d) What happens if the potential divider is brought between X and Y at 2Hz?
Ans: The ring will oscillate back and forth at 2Hz

----------------------------
My intuition tells me that the ring should be attracted to the solenoid, just like a normal metal to a bar magnet, regardless of change in flux, or polarity.
 
Last edited by a moderator:
Physics news on Phys.org
There are two effects going on here and I think you are right that the iron ring will be attracted in parts a, b, c, and d. Should have been a copper ring to avoid confusion?
 
i have come up with the following. Can anyone evaluate how correct i am? Correct me if i am wrong please.

When the switch is on, the split second duration for which the magnetic flux is changing within the ring, will cause an induced current, and a Bfield in the ring to oppose the change. HENCE, the ring will not move throughout this 'split second' as the Bfield cancels out.
After the magnetic flux becomes steady, the iron ring, like all ferramagnetic material, gets attracted to the stronger side of the Bfield, which is towards the solenoid.
The iron ring will remain attracted to the solenoid despite other changes in resistance.

Anyone and everyone please evaluate my answer!
 

Similar threads

Replies
7
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 18 ·
Replies
18
Views
4K
Replies
9
Views
3K
Replies
1
Views
9K
  • · Replies 6 ·
Replies
6
Views
16K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 10 ·
Replies
10
Views
8K
Replies
3
Views
2K
Replies
13
Views
2K