• Support PF! Buy your school textbooks, materials and every day products Here!

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

  • #1
Member advised to use the homework template for posts in the homework sections of PF.

Answers and Replies

  • #2
Charles Link
Homework Helper
Insights Author
Gold Member
4,529
1,929
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.
 
  • #3
Perfect answer, thank you so much! That totally clears me up.
 

Related Threads on When do I use Biot-Savart Law vs. Ampere's Law?

  • Last Post
Replies
1
Views
2K
Replies
1
Views
476
Replies
4
Views
3K
Replies
11
Views
22K
  • Last Post
Replies
1
Views
587
  • Last Post
Replies
3
Views
9K
  • Last Post
Replies
6
Views
4K
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
3
Views
873
Top