# Current and magmetic flux?

1. May 14, 2015

### ecobubble

Consider a straight infinite wire that carries a current I. Suppose you place a square circuit near the wire such that the circuit and the wire lie on the same plane. The length of the sides of the circuit is l`. The nearest side of the rectangle is at a distance d from the wire.
question is that; What is the magnetic flux that goes through the circuit?
and If the current in the infinite wire is changing constantly, i.e dI/ dt = c = constant, what is the current running in the circuit?
any idea? thanks your attention..

2. May 14, 2015

### Hesch

Calculate B(x,y) inside the square circuit, using Amperes law.

Find the flux: ψ = square B(x,y) ⋅ dA

You cannot find the current but the emf in the loop:

emf = dψ/dt

But if you know the resistance in the loop, you can find the current, using Ohms law.