GCSE truck magnetism question

Apr 2019
2
0
Hello,
I have just completed a past paper and I am not sure the answer to this question -

I originally thought it was a, but it turned out to be d. Why is this?
Thanks, Archie.
https://imgur.com/a/SXBb3q0
 

topsquark

Forum Staff
Apr 2008
2,967
627
On the dance floor, baby!
Hello,
I have just completed a past paper and I am not sure the answer to this question -

I originally thought it was a, but it turned out to be d. Why is this?
Thanks, Archie.
https://imgur.com/a/SXBb3q0
They seem to be assuming that the walls of the truck are metallic. When magnetic field lines intersect the surface of a metal the lines come out perpendicular to the metal.

-Dan
 
Apr 2017
523
126
.. When magnetic field lines intersect the surface of a metal the lines come out perpendicular to the metal.-Dan
I don't think that's right , Dan ....

The answer is definitely d ... the mythical 'lines of force' will prefer to move through the steel chassis of the truck rather than the air inside ... the steel is more 'magnetic' so gives an easier path.
 
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Jun 2016
1,182
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England
I think "mythical" is a bit strong...
It's perhaps an imperfect analogue used to describe what is actually happening,
but it is describing a real phenomenon.
 
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topsquark

Forum Staff
Apr 2008
2,967
627
On the dance floor, baby!
I don't think that's right , Dan ....

The answer is definitely d ... the mythical 'lines of force' will prefer to move through the steel chassis of the truck rather than the air inside ... the steel is more 'magnetic' so gives an easier path.
Sorry, I wasn't being clear enough. I agree that the answer is d).

-Dan