Help on magnetic field homework please

In summary, the magnetic field in point P (center of square) has a magnitude of .2m and a direction of going into the page.
  • #1
student85
138
0
Hello, I need help on understanding a concept in magnetic fields.
I have this homework were 4 long wires are parallel and viewed from on top they look as follows:

O - - - .2m - - - O
l l
l l
.2m .P .2m
l l
l l
O - - - .2m - - - O

So they form a square. What I need to find is the magnetic field in point P (center of square), magnitude and direction. The two wires on the right have electric currents emerging (going out of the page) and the two on the left have i going into the page. The values for all four of them are 5A.
I got the answer with me I just don't understand why the resulting magnetic field in P has its direction as going into the page.

Pleeease help. Any response is appreciated.


EDIT: for some reason the drawing doesn't come up right and two sets of lines appear together on the left side. Well it's supposed to be a square with each side being .2m
 
Last edited:
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  • #2
FYI, you can get it to space correctly like this:
edit: well, the figure still didn't quite come out, but it's closer :wink:

Code:
O - - - .2m - - - O
l                       l
l                       l
.2m       .P        .2m
l                       l
l                       l 
O - - - .2m - - - O

I don't think that the magnetic field should point into the page though, I think it should point down. I'm just using the right hand rule here, stick your right thumb in the direction of the current and the direction that your fingers wrap around is the direction of the magnetic field. Using that method you should be able to see that the magnetic field generated by all of the wires is in the plane of the paper and the horizontal components will cancel out.
 
  • #3
Ok thanks. Yeah that is exactly what I thought.
Damn I misunderstood the book. Yes I'm right! Thanks anyway!
 

1. What is a magnetic field?

A magnetic field is a region in space where a magnetic force can be detected. It is created by moving electric charges, such as electrons, and is represented by magnetic field lines.

2. How do I calculate the strength of a magnetic field?

The strength of a magnetic field can be calculated using the formula B = μ0I/2πr, where B is the magnetic field strength, μ0 is the permeability of free space, I is the current, and r is the distance from the current.

3. What is the difference between a magnetic field and an electric field?

A magnetic field is created by moving electric charges, while an electric field is created by stationary electric charges. Additionally, magnetic fields are perpendicular to electric fields and can only be detected by moving charged particles, while electric fields can be detected by both stationary and moving charged particles.

4. How does the direction of a magnetic field relate to the direction of current?

The direction of a magnetic field is perpendicular to the direction of current flow. This is known as the right-hand rule, where the thumb represents the direction of current and the fingers point in the direction of the magnetic field.

5. What are some real-life applications of magnetic fields?

Magnetic fields have many practical applications, such as in motors, generators, speakers, and MRI machines. They are also used in compasses, credit cards, and data storage devices.

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