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

Electromagnetic field

  • #1

Homework Statement



A 1400 nF capacitor with circular parallel plates 1.0 cm in diameter is accumulating charge at the rate of 25.0 mC/s at some instant in time. What will be the magnitude of the induced magnetic field 9.0 cm radially outward from the center of the plates?
T
What will be the magnitude of the field after the capacitor is fully charged?
T



Homework Equations



Obviously i'm a little confused, but I believe the general equation is B=mevE where B is magnetic field, e is c^2/Nxm^2, m is Nxs^2/C^2...on second, thought, i'm very confused.
another possibility is B=(mu) initial x I/ 2 pi r

The Attempt at a Solution



1400x25=35000x(1/9)=3888.89T
 
Last edited:

Answers and Replies

  • #2
marcusl
Science Advisor
Gold Member
2,714
381
Well some of your comments are on the right track. First you need to calculate the current, given the charge per second. Then use that current in your secon equation (often called the law of Biot and Savart).

However, don't forget to look at the units!! You can't just plug in 25 without making use of its units milli-Coulomb.
 

Related Threads on Electromagnetic field

  • Last Post
Replies
1
Views
908
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
2
Views
4K
  • Last Post
Replies
3
Views
4K
Replies
1
Views
10K
  • Last Post
Replies
2
Views
881
Replies
4
Views
952
  • Last Post
Replies
7
Views
336
  • Last Post
Replies
10
Views
2K
Replies
3
Views
2K
Top