# Homework Help: Magnetoelectric induction, I think

1. Jun 7, 2009

### Dante68

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

All I've been given concerning this problem is the diagram below and the instruction to solve for the total voltage at both voltmeters.

Unfortunately, I am not sure whether this configuration counts as a electromagnetic coil, or whether it is simply two single-wire circuits, one for each voltmeter, connected at Points A and B. It also isn't clear from the diagram whether voltmeter #1, and its associated circuit, is in the same plane as the other voltmeter.

The known data:
radius = .1m (A = .01pi)
magnetic flux density = 100w/m^2 or 100 Teslas
frequency = 1000 kHz

2. Relevant equations

I have been assuming that this each circuit is a coil (with one turn) and that I can use Faraday's Law: EMF = dphi/dt

where phi = the magnetic flux = B*A*cos(theta)

3. The attempt at a solution

Quite frankly, I'm stuck. I'm not sure what 'theta' represents. B*A = 100w/m^2*.01m^2*pi = pi webers, so flux = pi * cos(theta). Is theta the angle of the coil? And once I get phi, how to I use Faraday's Law?

#### Attached Files:

• ###### problem.jpg
File size:
28.3 KB
Views:
57
Last edited: Jun 7, 2009
2. Jun 8, 2009

### tjkubo

I am not sure about the diagram, but since they say that the magnetic field is a sine wave, the magnetic field B must vary with time. Write B as a function of time.