# Homework Help: Current Q

1. Dec 9, 2008

### shannon

1. The problem statement, all variables and given/known data
A WxH rectangular loop of wire, with resistance R, lies on a table a distance s from a separate long straight wire carrying a current I.
If the loop is pulled to the right, parallel to the wire, with the speed v, then what is the magnitude of the current induced on the loop?

2. Relevant equations

3. The attempt at a solution
I found that (a distance r away)
dφ=B•dA=(µₒI/2π)Wdr
now, to find φ
φ=(µₒI/2π)∫dr/r
I'm not sure about these limits.....I was thinking from W->W+c (where c is just a constant)
But I'm not sure...
From here I was going to use the equations:
ε= -dφ/dt
I=ǀεǀ/R

2. Dec 10, 2008

### alphysicist

Hi shannon,

Was there more information given? I think it matters which side of the rectangle is parallel to the long wire.

Also, I think it would be better to consider this as a motional emf problem rather than directly calcuating the loop flux. Does that help?