how is the answer D? (1 Viewer)

svad

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flux density = flux/area. therefore smaller one has grater flux density as it has smaller area. Smaller denominator = bigger flux density --> You can cross out A. They have the same amount of x's therefore same amount of flux --> Cross out C and B. Therefore it's D)
 

cheesynooby

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flux density = flux/area. therefore smaller one has grater flux density as it has smaller area. Smaller denominator = bigger flux density --> You can cross out A. They have the same amount of x's therefore same amount of flux --> Cross out C and B. Therefore it's D)
so is there actually a way of showing that its D on its own or can you only conclude that from eliminating everything else
 

wizzkids

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Remember that these drawings are just a model of magnetic flux. The number of crosses or dots represents the magnetic flux. This is the model that Michael Faraday invented. Faraday postulated that there was some sort of magnetic fluid that flowed from north poles to south poles, the magnetic flux.
In reality there is no flux; there is nothing flowing.
There is just the magnetic field, and it is a vector field, so it has magnitude and direction. Field intensity is measured in Tesla, and 1 Tesla = 1 Weber per square metre.
The more of these little vectors we draw per square metre, then the more intense (strong) the field is.
 

anonymoushehe

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flux density = flux/area. therefore smaller one has grater flux density as it has smaller area. Smaller denominator = bigger flux density --> You can cross out A. They have the same amount of x's therefore same amount of flux --> Cross out C and B. Therefore it's D)
but since the magnetic field strengths are different and the area wouldnt that mean they would have different fluxes
 

anonymoushehe

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but since there are the same number of crosses and their difference is the area wouldnt that mean the magnetic flux is different?
Remember that these drawings are just a model of magnetic flux. The number of crosses or dots represents the magnetic flux. This is the model that Michael Faraday invented. Faraday postulated that there was some sort of magnetic fluid that flowed from north poles to south poles, the magnetic flux.
In reality there is no flux; there is nothing flowing.
There is just the magnetic field, and it is a vector field, so it has magnitude and direction. Field intensity is measured in Tesla, and 1 Tesla = 1 Weber per square metre.
The more of these little vectors we draw per square metre, then the more intense (strong) the field is.
so when we look at these diagrams, should we only consider the distances between the crosses as the only significant part of these drawings since they indicate the magnetic field strength? so if the second one was to have the same magnetic field strength as the first square, the crosses would be closer together like the crosses in the first?
 

C2H6O

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but since the magnetic field strengths are different and the area wouldnt that mean they would have different fluxes
For hsc physics flux can be thought of as the number of field lines, so as both squares have 9 lines they have the same flux
 

wizzkids

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So when we look at these diagrams, should we only consider the distances between the crosses as the only significant part of these drawings since they indicate the magnetic field strength? If the second one was to have the same magnetic field strength as the first square, the crosses would be closer together like the crosses in the first?
That is correct. The spacing between the crosses (or dots) indicates the strength of the B-field.
For questions about the motor effect, you must use the strength of the B-field.
However, if you are dealing with a question about electromagnetic induction (Faraday's Law)

then you will be given a scenario involving a conducting loop of a certain area A, and you have to figure out how the amount of flux inside the loop is changing with time.
 

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