Circular loop magnetic field

  • Thread starter syhpui2
  • Start date
  • #1
28
0

Homework Statement



As shown in the figure below, a circular loop of radius a = 0.1 m lies in the horizontal x-y plane with its center located at the origin, with steady current I = 2.0 A circulating in a counter-clockwise direction in the loop. The magnetic field strength B(0,0,z) at the observation point (x, y, z) = (0, 0, 0.1 m) and its direction, due to the current I flowing in the circular loop is:
(a) B(0,0,z=0.1m) = 0.628 × 10-7 T, -z direction
(b) B(0,0,z=0.1m) = 2.323 × 10-6 T, +z direction
(c) B(0,0,z=0.1m) = 3.678 × 10-6 T, -z direction
(d) B(0,0,z=0.1m) = 4.443 × 10-6 T, +z direction

Answer is D

http://i.imgur.com/i6Zxf.png

i6Zxf.png


Homework Equations



Ampere's Law

The Attempt at a Solution



I tried Ampere's law, but I am not sure what is B dot dl (especially angle) and what is the path in this case...

Thx
 

Answers and Replies

  • #3
dynamicsolo
Homework Helper
1,648
4
I believe you want the Biot-Savart Law, since we are dealing with a current loop, rather than a current-carrying straight wire.

At any point on the loop, which way does the magnetic field circulate? At the observation point, what is going to happen to the "horizontal components" (the parts parallel to the xy-plane) of all the bits of magnetic field coming from the loop? What will that mean as far as how the bits of magnetic field add up at ( 0, 0, 0.1 m.)?
 
  • #5
28
0
I believe you want the Biot-Savart Law, since we are dealing with a current loop, rather than a current-carrying straight wire.

At any point on the loop, which way does the magnetic field circulate? At the observation point, what is going to happen to the "horizontal components" (the parts parallel to the xy-plane) of all the bits of magnetic field coming from the loop? What will that mean as far as how the bits of magnetic field add up at ( 0, 0, 0.1 m.)?
At any point on the loop, which way does the magnetic field circulate?

Up, by RHR



At the observation point, what is going to happen to the "horizontal components" (the parts parallel to the xy-plane) of all the bits of magnetic field coming from the loop?

Bcos(45)?

What will that mean as far as how the bits of magnetic field add up at ( 0, 0, 0.1 m.)?


integral Bcos(45)dl?
 
  • #6
ehild
Homework Helper
15,543
1,909
Thanks. But there is an angle in this case....
If you scroll down the page you arrive at the title "Magnetic field on the axis".

ehild
 
  • #7
28
0
If you scroll down the page you arrive at the title "Magnetic field on the axis".

ehild
Okay. Thanks
 

Related Threads on Circular loop magnetic field

  • Last Post
Replies
6
Views
3K
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
6
Views
5K
Replies
2
Views
11K
Replies
5
Views
2K
Replies
17
Views
6K
Replies
1
Views
134
  • Last Post
Replies
2
Views
11K
Replies
1
Views
6K
Replies
9
Views
10K
Top