Sunday, January 18, 2009

Ferromagnetism + Domain Theory + Right Hand Rule

Hey guuuise! Ingrid here, I decided to be awesome and steal Matthew's scribe job from Friday :]

Anywhoots, we had another sub, Mrs. Karras I believe, and we went over several things.
We received a booklet on Ferromagnetism and the Domain Theory of Magnetism, we were given about 15 mins to read through it and then answer the questions at the back of the book. We were also given notes on Oersted's Discovery/The Right Hand Rule.

Here are the answers to the questions from the booklet:
1) To magnetize a steel nail, you can either rub it against an already permanent magnet, or simply place it in a magnetic field. In order to lose it's magnetization, you can heat the magnet or remove it from the magnetic field (i.e. drop it).

2) In order for such an occurrence to, well- occur, the cans would have to be made out of a ferromagnetic material. Therefore, the cans are not made of aluminum because aluminum is not a ferromagnetic material, thus it would not be affected by a magnet.

3) One end of the known magnet would be attracted towards the ferromagnetic material (iron) and the other end would repel the permanent magnet.

4) The purpose of the Van Allen belt it to protect us from the Solar Wind, if it did not exist then we would be bombarded with solar radiation from the sun.


Okay, here are the notes on the Right Hand Rule(s). They were already super straightforward so I just copied it as it was.

Oersted's Discovery
Oersted showed a connection between electricity and magnetism. If a current is flowing in a straight wire, a magnetic field is created, in cocentric circles, around the wire.

First Right Hand Rule

Grasp the wire with your right hand. Keep your thumb pointed in the direction of the conventional (positive) current flow. The fingers of your hand circle the wire and point in the direction of the magnetic field.

Second Right Hand Rule

The direction of the field produced by an electromagnet can be found by using this rule.
Grasp the coil with your right hand. Curl your fingers around the loops in the direction of the conventional (positive) current flow. Your thumb points toward the N-pole of the electromagnet.

Third Right Hand Rule

The direction of the force on a current carrying wire in a magnetic field can be found using this rule.
Point the fingers of your right hand in the direction of the magnetic field. Point your thumb in the direction of the conventional (positive) current flow in the wire. The palm of your hand then faces in the direction of the force acting on the wire.

Here's a cheap diagram I drew for you guys as a guide, pls excuse the ugliness:

Next scribe... Will be Matthew?

1 comment:

Ms K said...

I like the diagram. Great post!