(adsbygoogle = window.adsbygoogle || []).push({});

Hi! Can anyone please tell me where this equation was derived from?

This equation is used to get the magnetic field (B).

I is current and r is the distance. And I think I understand the Meu. And yet I have no idea where the 2pi came from. I looked in my textbook, internet and asked friends but nobody seems to know.

Thank you!

**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: Magnetism - the proportionality constant question

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