The discussion revolves around the behavior of a steel rod and an iron rod placed inside a solenoid with alternating current (AC). Participants explore the effects of AC on the magnetization of the rods, considering factors such as frequency and material properties.
The discussion is active, with participants sharing various perspectives on the effects of AC on the rods. Some guidance has been provided regarding the properties of steel and iron, and the implications of changing magnetic fields. Multiple interpretations of the scenario are being explored, particularly concerning the magnetization and interaction of the rods.
Participants note that the original question involved a comparison between DC and low-frequency AC currents, and there is some confusion regarding the specifics of the question. The discussion also touches on the educational context, with references to different syllabi and levels of understanding in magnetism.
technician said:If you have low frequency AC then the bars will become magnetised with changing magnetic polarity. The bars could repel each other although the fact that one bar is steel and the other is iron will produce different strengths so ...? Not sure !
At higher ( mains) frequencies I think you are maybe correct!...I know that mains AC solenoids can be used to demagnetize steel bars by withdrawing them slowly.
I imagine there is not one simple answer.
what happens? I think nothing...
gsal said:That's probably not true, right? I mean nothing does not happen...I am sure something happens, it is a matter of whether what happens is of interest to you or not or whether it affects you or not...so, maybe some context would have been nice.
Maybe the rods do not get magnetized because of the changing magnetic field, but something happens...because the relative motion between the magnetic field and the rods, eddy currents will be induced into the rods and they will heat up due to their internal resistance...certainly the iron rod, I don't know about the steel one, if by making it out of steel, they meant non-magnetic steel?
The question just said, if the dc current was changed to a low frequency ac current, describe what will happen to the rods and explain why
gsal said:Nope, the original posting said absolutely nothing about dc.[/Q
It was a three part question (a) when a steel and iron rod is placed inside a solenoid with a dc current explain what happens (b) what if its iron and copper rod (c) what happens if the experiment was repeated in (a) but a low frequency ac current was used instead of dc.
Steel won't be magnetised easily right? But the magnetic field will still pass through it and change direction. So since its the magnetic field that causes the attraction/repulsion so both the iron and steel will still repel each other?
Besides this, I'm not sure why when I draw magnetic field lines of a magnetic shielding object eg iron, the iron won't get magnetised as well. Because I only draw the lines of the magnet passing through the iron so I'm unsure about this too.
technician said:If you have low frequency AC then the bars will become magnetised with changing magnetic polarity. The bars could repel each other although the fact that one bar is steel and the other is iron will produce different strengths so ...? Not sure !
At higher ( mains) frequencies I think you are maybe correct!...I know that mains AC solenoids can be used to demagnetize steel bars by withdrawing them slowly.
I imagine there is not one simple answer.
I don't quite get it, slowly is meant to demagnetise it, but I'm still unsure about what if the observations in this case.NascentOxygen said:To demagnetise a steel object you slowly withdraw it from within a strong AC field. Emphasis on the "slowly".