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Contradictory Physics (1 Viewer)
- Thread starter SlaminSammy
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If you want to demonstrate the meisner effect all you have to show is magnetic levitation i.e. two magnetic fields oppsing each other producing levitation of a magnet. The simplest answer is a cradle with one magnet over another with south to south and north to north. The one on top won't touch the other, presto! miesner effect.
No say.
Codey that is an example of magnetic levitation but is not an example of the Meissner effect, so is not what they are after in the context of the syllabus. It is based on the same forces but as they showed in 2003, they want you to explain magnetic levitation for superconductors.
Codey that is an example of magnetic levitation but is not an example of the Meissner effect, so is not what they are after in the context of the syllabus. It is based on the same forces but as they showed in 2003, they want you to explain magnetic levitation for superconductors.
so did ours but it really is the effect. No they don't fly off because you have a cradle to stop them turning around (some nails). Sylabus dot point says "perform an investigation to demonstrate magnetic levitation". That's what I answered. But the next one "analyse.....magnet is able to hover above a superconductor....superconducting" i see your point. I guess the only way around is to disregard the ability to exclude the magnetic field and prattle on about how the induced current creates it's own magnetic field Yadda yadda lenz's law yadda yadda causing meisner effect. but the meisner effect really is only the floating part i think.
Codey it is the effect of magnetic levitation but it is not the Meisner Effect.
As I have been told constantly by the Board of Studies:
"However in programming the content needs to be considered in relation to the
contextual statements in column 1 and several dot points in 9.4.2 and 9.4.3
rather than in isolation"
Meaning, you need to look at each dot point, in context to the paragraph at the start and columns 1 and 2. That is telling you the specific magnetic levitation they are after is the meisner effect.
If they ask a question to describe your prac, then their probably would be lee-way given but in an explanation, they will be after the meissner effect using superconductors.
As I have been told constantly by the Board of Studies:
"However in programming the content needs to be considered in relation to the
contextual statements in column 1 and several dot points in 9.4.2 and 9.4.3
rather than in isolation"
Meaning, you need to look at each dot point, in context to the paragraph at the start and columns 1 and 2. That is telling you the specific magnetic levitation they are after is the meisner effect.
If they ask a question to describe your prac, then their probably would be lee-way given but in an explanation, they will be after the meissner effect using superconductors.
The Meissner effect is a specific property of superconductors.
http://hyperphysics.phy-astr.gsu.edu/hbase/solids/meis.html#c2
An example of the Meissner effect is magnetic levitation above a supermagnet.
http://hyperphysics.phy-astr.gsu.edu/hbase/solids/meis.html#c2
An example of the Meissner effect is magnetic levitation above a supermagnet.
Fair enough. Since you have the best knowledge of this particular area. Could you answer this as an exam style 6 mark question....promise i wont copy lol. it is observed when the critical temperature of a superconductor is reached that a small magnet begins to levitate and hovers above the superconductor. Explain why the magnet begins to levitate once the super conductor has been cooleed to the critical temperature. ( success one hsc, specimen questions.)
I would first draw a diagram, showing the magnet suspended above the superconductor. On the diagram, I would label the Weight force down and the magnetic force up, with both arrows being of equal length.
Underneath the diagram.
Underneath the diagram.
- This is an example of the Meissner Effect
- When the temperature dropped below the critical temperature a superconductor forms that actively stops the magnetic field from penetrating the surface of the superconductor
- The superconductor does this by having currents induced inside the superconductor.
- These induced currents produce a magnetic field that opposes the magnetic field of the original magnet, resulting in a force that is pushing up on the magnet.
- As the magnetic force and gravitational force acting on the magnet are of equal strength and opposite direction, there is a zero net force. Therefore the magnet is suspended.
SlaminSammy
Member
ANd this whole lenzs law and induced currents is wrong... The meisner effect is way out of the scope of the capability of hsc students. The calcualtions involved to actually provide and explaination of why a magnet will levitate is absurdly crazy and to difficult for even the most capable 4 unit mathematics student.
Lets say hyperthetically that this induced current thing is correctomundo... we place a magnet above a superconducting material cooled below its critical temperature... the magnet will fall and (if we dissagree with the concept that a superconductor is a diamagnetic material - which by its own very meaning - will not allow a magnetic field to penetrate its surface - provides a reason for the contradiction) the changing magnetic flux will induce a current that will be equal in magnitude but opposite in direction to the magnetic field of tha magnet and this will result in the magnet hovering. However... what hapens then. the magnet no longer falls and there is no longer a changing magnetic flux... so either faradays law is violated and currents are induced... or the concept of the meisner effect which the textbooks talk about is completely bunk.
think about it!
Lets say hyperthetically that this induced current thing is correctomundo... we place a magnet above a superconducting material cooled below its critical temperature... the magnet will fall and (if we dissagree with the concept that a superconductor is a diamagnetic material - which by its own very meaning - will not allow a magnetic field to penetrate its surface - provides a reason for the contradiction) the changing magnetic flux will induce a current that will be equal in magnitude but opposite in direction to the magnetic field of tha magnet and this will result in the magnet hovering. However... what hapens then. the magnet no longer falls and there is no longer a changing magnetic flux... so either faradays law is violated and currents are induced... or the concept of the meisner effect which the textbooks talk about is completely bunk.
think about it!
rama_v
Active Member
In Chemistry the cathode is postiive only in a galvanic cell. In an electrolytic cell, the cathode is negativeKomaticom said:
Xayma
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If you look at the definitions of a cathode and anode they are the same in both subjects.
I suggest you also look at the module Shipwrecks, conservation and restoration or something similar in chemistry. It also uses the same convention of signs for anodes and cathodes as physics does but all three stay under the same definition.
I suggest you also look at the module Shipwrecks, conservation and restoration or something similar in chemistry. It also uses the same convention of signs for anodes and cathodes as physics does but all three stay under the same definition.