Relationship between emf and magnetic field strength

AI Thread Summary
The discussion centers on the relationship between electromotive force (emf) and magnetic field strength, particularly in the context of a homework problem. It clarifies that there is no motional emf in the scenario since the coil is stationary, leading to the conclusion that the induced voltage is zero. Participants emphasize the importance of using Faraday's law of induction, which states that emf is related to the rate of change of magnetic flux rather than the magnetic field strength itself. The conversation highlights a common misunderstanding about the direct relationship between emf and magnetic field strength. Ultimately, the clarification helps participants grasp the correct application of the principles involved.
mingee kim
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Homework Statement


See image below.

Homework Equations


motional emf = induced voltage = B L v

The Attempt at a Solution


I thought the answer would be A since there's a direct relationship between EMF and magnetic field strength. The answer is D.
 

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Welcome to PF!

You do not have any motional emf in this problem since the coil is not moving (v = 0).

Try using the most general form of Faraday's law of induction.
 
TSny said:
Welcome to PF!

You do not have any motional emf in this problem since the coil is not moving (v = 0).

Try using the most general form of Faraday's law of induction.
Doesn't Faraday's law of induction say the same thing? that emf is related to the rate change of magnetic flux? and magnetic flux = BA cos theta

so the emf is related to the magnetic field strength?
 
mingee kim said:
Doesn't Faraday's law of induction say the same thing?
I'm not sure what you mean by the "same thing" here.

that emf is related to the rate change of magnetic flux? and magnetic flux = BA cos theta
Yes, good.

so the emf is related to the magnetic field strength?
Would it be more appropriate to say that emf is related to the rate of change of B?
 
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mingee kim said:
Doesn't Faraday's law of induction say the same thing? that emf is related to the rate change of magnetic flux? and magnetic flux = BA cos theta

so the emf is related to the magnetic field strength?
TSny said:
ropriate to say that emf is related to the rate of change of B?
Ahh, it makes sense now. Thank you!
 
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