Help Me Understand: Magnetic Flux Problem Solution

In summary, the solution attached involves two periods of rotation to consider. The first interval involves a decrease in the area relative to the perpendicular B field, followed by an increase in the area. This can be visualized by flipping a piece of paper, where the area decreases to a minimum when the plane is parallel to the B vectors and then increases again.
  • #1
pyroknife
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I'm having problems understanding this solution (attached.) I don't understand how they got 2*magnetic flux out of the change in the magnetic flux in the bottom of the attachment. Can someone explain that to me?
 

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  • #2
Essentially there are two periods of rotation that need to be considered. For the first interval, the area is decreasing from its maximum to minimum value (relative to the perpendicular B field). Moreover, an interval follows such that the area that the flux is passing through is increasing from its minimum to maximum value.
 
  • #3
sandy.bridge said:
Essentially there are two periods of rotation that need to be considered. For the first interval, the area is decreasing from its maximum to minimum value (relative to the perpendicular B field). Moreover, an interval follows such that the area that the flux is passing through is increasing from its minimum to maximum value.

Thanks I figured it would be something like that, but I don't understand why there are 2 periods, is this kind of a fixed case?
 
  • #4
Visualize the coil being flipped over. At first, the flux lines are passing through a maximum area, and as time proceeds, the area decreases (since the coil is being flipped, less flux is passing through) until it reaches its minimum (no flux). It then starts to increase its area as it continues to be flipped.

Take a piece of paper and flip it. Assume the B field is pointing down. As you are flipping the piece of paper, the area which the b field passes through decreases to a minimum when its plane is parallel to the B vectors, then increases until it is at a 90 degree angle.
 
  • #5


Sure, I would be happy to explain the solution to you. First, let's define what magnetic flux is. Magnetic flux is a measure of the flow of magnetic field through a given area. It is represented by the symbol Φ and is measured in units of webers (Wb). Now, in the attached solution, we are dealing with a change in magnetic flux, which is represented by the symbol ΔΦ.

In order to understand how the solution arrived at 2*magnetic flux, we need to look at the equation for magnetic flux, which is Φ = B*A*cos(θ), where B is the magnetic field strength, A is the area, and θ is the angle between the magnetic field and the area. In this problem, the area is constant, so we can ignore it for now.

Now, let's look at the change in magnetic flux, which is given as ΔΦ = Φ2 - Φ1, where Φ2 is the final magnetic flux and Φ1 is the initial magnetic flux. This means that the change in magnetic flux is equal to the final magnetic flux minus the initial magnetic flux.

In the solution, it is given that the initial magnetic flux is zero, which means that Φ1 = 0. Now, let's look at the final magnetic flux, which is given as Φ2 = 2*magnetic flux. This means that the final magnetic flux is equal to twice the magnetic flux, or Φ2 = 2*Φ.

Substituting these values into the equation for change in magnetic flux, we get ΔΦ = 2*Φ - 0 = 2*Φ. This is where the 2*magnetic flux comes from in the solution.

I hope this explanation helps you understand the solution better. It is important to remember the definition of magnetic flux and the equation for change in magnetic flux in order to fully understand the solution. If you have any further questions, please let me know.
 

1. What is magnetic flux?

Magnetic flux is the measure of the amount of magnetic field passing through a given area. It is represented by the symbol Φ.

2. What is the equation for magnetic flux?

The equation for magnetic flux is Φ = B x A x cos(θ), where B is the magnetic field strength, A is the area, and θ is the angle between the magnetic field and the surface.

3. How do you calculate magnetic flux?

To calculate magnetic flux, you need to know the magnetic field strength, the area, and the angle between the field and the surface. Simply plug these values into the equation Φ = B x A x cos(θ) to get the magnetic flux value.

4. What are some real-world applications of magnetic flux?

Magnetic flux is used in a variety of applications, including electric motors, generators, transformers, and MRI machines. It is also used in the study of Earth's magnetic field and in the production of electricity through renewable energy sources like wind and hydro power.

5. How does magnetic flux affect materials?

Magnetic flux can have different effects on different materials. Some materials, called ferromagnetic materials, are strongly affected by magnetic flux and can become magnetized. Other materials, such as diamagnetic materials, are weakly affected and can become slightly repelled by magnetic fields.

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