Introduction to Magnetic Force

Our introduction to magnets began by determining what the comic joke meant to represent. My guess was right: a bar magnet. Carlos decided to put "Magneto from X-Men."

On a more serious note, we were asked to sketch the relationship of a compass and a bar magnet  with lines. In addition to the lines, we also found that the North pin was attracted to the South side of the magnet.

Using iron filings, we were able to visually see the magnetic field lines created by the magnet.

We were then asked to find the flux lines using Gauss' Law. In the surface encompassing the whole field, the flux was zero. The flux encompassing only one side of the magnet had the flux equal to the lines that were inside it.

The compass.

The compass and a magnetized pin that was broken in half. It turns out that even though according to Gauss' law there has to be only one magnetized side when the magnet is cut in half, a magnet will always have a North and a South side. It is physically impossible to create a one sided magnet.

These are the equations for an electrical and magnetic Gauss' Law. With our findings from earlier, it is concluded that the net magnetic flux will always be zero.

Professor Mason then used a bar magnet to manipulate the electron inside a cathode tube. The electron movement was always perpendicular to that of the bar magnet.

That physical evidence shows that the relationship between a magnetic field and a charge will be a cross product: F = qV x B ( F, V and B being vectors).

Using the right hand rule, we are also able to determine in which direction each vector points.

We were then given a sample problem. The goal was to find the force and remembering that phi is equal to 90 - theta, we were able to find the force on this particular equation to be 6.24 * 10^-16 in the negative direction.

This is a microwave gun. A power source emits electrons into the antenna which then produces a microwave.

This is the front view of the microwave gun. It was safer NOT to shoot it in the lab.

This is a very strong horse shoe magnet.

If a wire was set up to run through the magnet and a current was also sent through, the wire would move up or down depending on the direction of the current. This is physically showing the force acting upon the wire when a charge is being interacted with a magnetic field.

Picture representation of the interaction is shown below.

This is the set up:

We were then asked what the force would be when a rectangular surface had a current running through it with some sort of magnetic field going inside the board. Using the right hand rule, the force would go in all directions, possibly stretching and compressing the surface.

And what if the same surface and current but the magnetic force was going to the left? Then there would be no force on points A and C but a force going into the board on point B and out of the board at point D. This interaction results in the surface to turn due to torque. However, when the surface is at 90 degrees, the surface will change direction and spin in the opposite direction.

When a wire is not straight, it is called a kinky wire. Because these wires are not straight, we have to use a different equation to find the force: dF = Idl x B.

With the given values, we were able to use excel to determine the total force being done on the wire.