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

Quick question about magnetic fields

  • #1
1. Homework Statement
The force on a wire .80 m long that is perpendicular to the Earth's magnetic field is .12 N. What current flows throught the wire? (Earth's magnetic field is 1.0x10^-4 T at the poles and 5.0x10^-5 T at the equator)

2. Homework Equations
Fm=BIl
Fm is magnetic force in N, B is magnetic field strength in telsa (T), and l is length in meters.

3. The Attempt at a Solution
I'm just not sure what I'm supposed to use for B. Do I use the strength at the poles? at the equator? Some combination of the two?

Thanks.
 

Answers and Replies

  • #2
dynamicsolo
Homework Helper
1,648
4
This certainly is a mysterious problem statement: doesn't it say anything about where on Earth the wire is? Maybe you're supposed to find the range of possible values for the current within the range of values for the local magnetic field strength. Since we're told that the wire is perpendicular to the local field, the "magnetic dip angle" (angle the field makes to the local horizontal) doesn't matter. It seems like there's something left out of the problem...
 

Related Threads for: Quick question about magnetic fields

  • Last Post
Replies
3
Views
1K
Replies
1
Views
2K
  • Last Post
Replies
1
Views
944
  • Last Post
Replies
3
Views
4K
  • Last Post
Replies
1
Views
1K
Replies
2
Views
3K
  • Last Post
Replies
3
Views
506
  • Last Post
Replies
5
Views
9K
Top