Hi everyone, long time lurker, first time poster. Can someone please clear this up for me? Two wires running parallel to each other. I think its just an algebraic addition of the usual(adsbygoogle = window.adsbygoogle || []).push({});

B(r)=u_0i/2pir

but instead of r, we are using D and d

aslso i apologise for my formulae, if someone could point me to the tex thread ill redo them

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

By summing the magnetic field due to currents of magnitude i flowing in both the wires in the senses you found in part (c), show that, on the line joining the two wires, the magnetic field strength is given by =

`````````````````````````````````````````````````````

2. Relevant equations

B(r)=u_0i/2pir

3. The attempt at a solution

B=(u_0i/2piD)+(u_0i/2pid)

which i get to be

B=(u_0i)/pi(D^2-d^2)

the question says it should be

B=(u_0iD)/pi(D^2-d^2)

Where is that extra D on the numerator from?

Thanks

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Addition of magnetic fields

**Physics Forums | Science Articles, Homework Help, Discussion**