Does the length of an iron bar changes when it is magnetised?

  • Thread starter Thread starter heman
  • Start date Start date
  • Tags Tags
    Iron Length
AI Thread Summary
The length of an iron bar can change when magnetized due to its magnetostrictive properties, which involve the alignment of its atomic structure in response to a magnetic field. This change in length is influenced by factors such as the bar's size, shape, and the strength of the magnetic field applied. The process of magnetization involves passing the iron through magnetic field lines, generating electrical currents that create heat and hysteresis. However, the resulting length change is often minimal and may be undetectable without precise instruments. Overall, while the theoretical basis for length change exists, practical observation may be challenging.
heman
Messages
353
Reaction score
0
Does the length of an iron bar changes when it is magnetised?
 
Physics news on Phys.org
Theoretically yes, because iron is a magnetostrictive ferromagnetic material. The experimental measurement of this variation depends on your setup (iron bar size&shape, magnetic field strength, etc.).
 
Clive,
That' okay but how CAN the length increase.
They are just aligning in the direction of magnetic field.
 
Let's see now. To magnetize iron you have to pass it through the field lines. Doing so generates an electrical current. Current meets resistance, generates heat, hysteresis. When you heat something what happens?
Mind you, with every day magnets, the effect could be so small that it would be undetectable without some veery precise instruments.
 

Thread 'Maxwell stress tensor'

This is from Griffiths' Electrodynamics, 3rd edition, page 352. I am trying to calculate the divergence of the Maxwell stress tensor. The tensor is given as ##T_{ij} =\epsilon_0 (E_iE_j-\frac 1 2 \delta_{ij} E^2)+\frac 1 {\mu_0}(B_iB_j-\frac 1 2 \delta_{ij} B^2)##. To make things easier, I just want to focus on the part with the electrical field, i.e. I want to find the divergence of ##E_{ij}=E_iE_j-\frac 1 2 \delta_{ij}E^2##. In matrix form, this tensor should look like this...
View full post »
Thread 'Applying the Gauss (1835) formula for force between 2 parallel DC currents'

Thread 'Applying the Gauss (1835) formula for force between 2 parallel DC currents'

Please can anyone either:- (1) point me to a derivation of the perpendicular force (Fy) between two very long parallel wires carrying steady currents utilising the formula of Gauss for the force F along the line r between 2 charges? Or alternatively (2) point out where I have gone wrong in my method? I am having problems with calculating the direction and magnitude of the force as expected from modern (Biot-Savart-Maxwell-Lorentz) formula. Here is my method and results so far:- This...
View full post »

Similar threads

I Coil Around A Tube - Iron Cylinder Inside Tube - How Many Turns Needed?
Replies
27
Views
3K
Magnet's attraction force on a piece of iron
Replies
1
Views
2K
I Force exerted by an iron core electromagnet on a ferrofluid
Replies
2
Views
2K
Calculate the inductance of a solenóide wound on an iron core
Replies
8
Views
17K
Does an iron ring shield a static magnetic field?
Replies
3
Views
2K
Determining The Magnetic Saturation of A Soft Iron Magnetic Core
Replies
7
Views
5K
I Iron core barely boosting field strength
Replies
43
Views
6K
What Happens to Orbital and Spin Momentum of Free Electrons in Iron?
Replies
2
Views
2K
Magnetic saturation and ferrite magnets
Replies
2
Views
4K
Why does an iron core increase magnetism?
Replies
5
Views
2K

Hot Threads

Recent Insights

Back
Top