Levitation (1 Viewer)

[Haku]

For a MC question asking u
"why does a magnet float on a superconductor cooled below its critical temp".

i tossed between this two option
1. Current induced in the conductor oppose the external magnetic field.
2. superconductors excludes magnetic field.

from what i read 1 is obviously more correct. But the answer says 2.

Could someone help.

 

[香港!]

For a MC question asking u
"why does a magnet float on a superconductor cooled below its critical temp".

i tossed between this two option
1. Current induced in the conductor oppose the external magnetic field.
2. superconductors excludes magnetic field.

from what i read 1 is obviously more correct. But the answer says 2.

Could someone help.

Hi... 1 says the Current induced opposes the external field... but shouldn't it be the opposing magnetic field produced by that current that makes the magnet hover??

 

[speed2]

Hi... 1 says the Current induced opposes the external field... but shouldn't it be the opposing magnetic field produced by that current that makes the magnet hover??

yeah it is the interaction of the two fileds that makes the magnet hover

 

[Haku]

no, cause a magnet brought near a superconductor would induce a current that would oppose the original movement of the magnet. In this case the magnet (lets say north) is trying to move down, so the induced current would create a field that oppose the external field and exactly cancell out so there is no net field. Isn;t that right?

cause i know that superconductors excludes Bfield but choice 1 describes how it does it, as the above states.

 

[Xenocide]

You are correct nosadness.

As a side note, only superconductors exhibit this effect (to this extent) as no current is lost due to resistance and hence the induced current/magnetic field is exactly equal to that which created it.

 

[Haku]

so is the stupid MC answer wrong which caused me so much confusion?

 

[serge]

i know that superconductors excludes Bfield

ON ANOTHER TOPIC- superconductors exclude magnetic fields until the magnetic field is so strong that the superconducting properties stop... hence the magnet stops hoveirng
and falls

 

[香港!]

no, cause a magnet brought near a superconductor would induce a current that would oppose the original movement of the magnet. In this case the magnet (lets say north) is trying to move down, so the induced current would create a field that oppose the external field and exactly cancell out so there is no net field. Isn;t that right?

cause i know that superconductors excludes Bfield but choice 1 describes how it does it, as the above states.

"so the induced current would create a field that oppose the external field and exactly cancell out so there is no net field. Isn;t that right?"
Exactly right!!
But look at your option number 1: "1. Current induced in the conductor oppose the external magnetic field."
As I said before, this option 1 doesn't say that the Magnetic Field induced by that current opposes the external magnetic field... It just says the current opposes the external magnetic field... Not like what YOU said as well, where the "induced current would create a field that oppose the external field"