Help with yr11 magnetic fields

In summary, the magnetic field at point C is zero because the direction of the field lines is perpendicular to the direction of the poles.
  • #1
JenL
12
0

Homework Statement


The diagram shows the magnetic field between like magnetic poles

Homework Equations


Point C is the exact middle of the region between the poles. Explain why the strength of the magnetic field at point C is zero?

The Attempt at a Solution


The like poles repel each other. In the center the magnetic fields are strongest and will be equal to each other? So they cancel out??

*Please I have only just started learning about Magnetic fields in class and I have tried looking this up but cannot seem to get the answer/ explanation
 
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  • #2
Hi JenL! :smile:
JenL said:
The like poles repel each other. In the center the magnetic fields are strongest and will be equal to each other? So they cancel out??

But why will they be equal to each other? :wink:

(Even if you think it's obvious, you have to give a reason)

btw, do you know about vectors?

do you know how vectors add (and when they add to zero)?​
 
  • #3
I asked one of my classmates and is it because in the center there are no magnetic fields lines? (in the diagrams there are no magnetic field lines in the center) so the center's magnetic field strength is 0.
I have learned about vectors in forces but I am not sure if that if the same?
 
  • #4
JenL said:
I have learned about vectors in forces but I am not sure if that if the same?

the field lines are a way of picturing the forces

force is a vector, so it has a magnitude (a strength) and a direction

the force at a point can be represented by an arrow at that point: the direction of the arrow shows the direction of the force, and the length of the arrow shows the strength of the force (at that point)

so one way of picturing a force field is by drawing little arrows (nearly) all over it

however, that can be confusing (if you've ever seen one, you'll know why)

so instead we join some of the arrows together, making very long (and curved) arrows … these are the field lines

the direction (the tangent) of the field line at any point shows the direction of the force at that point, and the magnitude is shown by how close together the lines are (because we lost the information of the length of the little arrows when we joined them up! :wink:)​

see also http://en.wikipedia.org/wiki/Field_Lines
… is it because in the center there are no magnetic fields lines? (in the diagrams there are no magnetic field lines in the center) so the center's magnetic field strength is 0.

i think the best way of answering the question (about the strength of the magnetic field at the midpoint) is to remember that the strength is the strength of a vector, and every vector must have a direction (unless its strength is zero) …

so which direction would the vector point in? :smile:
 
  • #5
right.*

Hi there, it's great that you're seeking help with understanding magnetic fields. I can provide some guidance on this subject.

First, let's define what a magnetic field is. A magnetic field is a region in which a magnetic force can be detected. It is created by moving electric charges, such as electrons, and is represented by lines of force that show the direction and strength of the field.

Now, let's look at the diagram provided. The diagram shows the magnetic field between like magnetic poles, meaning that both poles are the same type (either north or south). In this case, the magnetic field lines will be pointing away from each other, as like poles repel each other.

Point C is the exact middle of the region between the poles. The strength of the magnetic field at point C is zero because the magnetic field lines from each pole cancel each other out at this point. This is because the magnetic field lines are pointing in opposite directions, so their effects cancel each other out, resulting in a net magnetic field strength of zero.

To better understand this concept, imagine two people pushing against each other with equal force. The point in between them where their forces cancel out would be similar to point C in this scenario.

I hope this explanation helps you better understand why the strength of the magnetic field at point C is zero. It's important to keep in mind that the strength of a magnetic field is dependent on the distance from the source of the field, as well as the strength of the source itself. As you continue to learn about magnetic fields, you will discover more about how they work and why they are important in various scientific fields. Keep up the good work!
 

What is a magnetic field?

A magnetic field is an invisible force that is created by moving electric charges. It is represented by lines of force that run from the north pole of a magnet to the south pole.

How do magnetic fields affect objects?

Magnetic fields can attract or repel certain objects, depending on their properties. For example, magnets will attract objects made of iron, but will not affect objects made of wood. Magnetic fields can also cause objects to align in a certain direction.

How are magnetic fields measured?

Magnetic fields are measured using a device called a magnetometer. This instrument can detect the strength and direction of a magnetic field. The unit of measurement for magnetic fields is called a Tesla.

What are some real-life applications of magnetic fields?

Magnetic fields have numerous applications in our daily lives. They are used in generators and motors, which power many of the devices we use. They are also used in medical imaging, such as MRI machines, to create detailed images of the body's internal structures.

How can I calculate the strength of a magnetic field?

The strength of a magnetic field can be calculated using the formula B = μ0*I/(2π*r), 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 source of the field.

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