# Relationship between emf and magnetic field strength

1. Feb 11, 2017

### mingee kim

1. The problem statement, all variables and given/known data
See image below.

2. Relevant equations
motional emf = induced voltage = B L v

3. 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.

#### Attached Files:

• ###### screenshot.png
File size:
28.6 KB
Views:
20
2. Feb 11, 2017

### TSny

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.

3. Feb 11, 2017

### mingee kim

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?

4. Feb 11, 2017

### TSny

I'm not sure what you mean by the "same thing" here.

Yes, good.

Would it be more appropriate to say that emf is related to the rate of change of B?

5. Feb 11, 2017

### mingee kim

Ahh, it makes sense now. Thank you!