1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: When do I use Biot-Savart Law vs. Ampere's Law?

  1. Jun 7, 2016 #1
    • Member advised to use the homework template for posts in the homework sections of PF.
  2. jcsd
  3. Jun 7, 2016 #2

    Charles Link

    User Avatar
    Homework Helper
    Gold Member

    In order to use Ampere's law, it is necessary to have some symmetry to the integral around the loop. i.e. for ## \oint B \cdot dl=\mu_o I ## , in a problem with radial symmetry,(such as a long straight current carrying conductor), the ## B ## is normally constant throughout the entire circular path that is chosen for the integral. For a linear symmetry, such as a long solenoid, a path of a thin rectangular loop is used. The ## B ## is assumed to be zero outside the solenoid (over the outer part of the path) and the ## B ## is assumed to have the same value on the entire length of the interior. Biot-Savart can also be used to solve these cases, but the Biot-Savart integrals are more difficult than the Ampere's law integrals. Meanwhile for a single circular current carrying loop, you don't have a symmetric path to use Ampere's law, and the Biot-Savart solution is necessary.
  4. Jun 7, 2016 #3
    Perfect answer, thank you so much! That totally clears me up.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted