# Induced emf is my answer correct ( not sure about b value)

1. May 18, 2012

### pokie_panda

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

The magnetic field perpendicular to a circular wire loop 6.8cm in diameter is changed from +0.39 T to -0.62 T in 160 m/s , where + means the field points away from an observer and - toward the observer.

2. Relevant equations

e=Blv

3. The attempt at a solution

e= 6.8 *10^-2 x 160 x .71/ (the difference) or is it 1.01 the 0.39 - 1.01 = -.62

2. May 18, 2012

### QuarkCharmer

I think you should be using Faraday's Law for this problem. Just keep in mind that they give you an average value for the change of B, but you need the derivative of the flux with respect to time.

3. May 20, 2012

### truesearch

Induced emf = rate of change of flux linkage.
You have been given the flux density,B,. Do you know how to calculate the flux through an area with diameter 6.8cm
Can you then calculate the change in flux per second?

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook