Ch. 14 Magnetism
Terms
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- Magnetic Fields
- Just like electric fields, magnets have fields. Lines go out of the north and into the south. Field is strongest near the poles.
- Galvanometer
- An instrument that measures the amount of current in a circuit.
- Faraday's Law
- An electric current can be produced in a circuit by a changing magnetic field.
- Domains
- Small groups of atoms whose magnetic fields are aligned in the same direction. Material that is not magnetized will have these that cancel each other out.
- Permanent Magnets
- Any piece of iron that can be made into a magnet. To magnetize you either need to rub it with a magnet or leave it near a strong magnet.
- Transformer
- A device that can change one alternating-current voltage to a different alternating-current voltage.
- Demagnetize
- Heat or hitting a magnet.
- Step-Down Transformer
- Has more loops of wire in the primary circuit. Produces less voltage throught the secondary circuit.
- Generator
- A device that uses electromagnetic induction to convert mechanical energy to electrical energy.
- Step-Up Transformer
- Has more loops of wire in the secondary circuit. It produces more voltage than in the primary circuit.
- Soft Magnets
- Easy to magnetize and to remove magnetism.
- Compass
- A magnet that floats or sits on a pivot. The needle will always point towards the south magnetic pole (northern geographic pole). It follows the field lines.
- Electromagnetic Induction
- The production of a current in a circuit by a change in the strength, position, or orientation of an external magnetic field.
- Lodestone
- A rock that is magnetic. It contains the mineral magnetite.
- Hard Magnets
- Difficult to magnetize and remove magnetism.
- Solenoid
- Current through a coil of wire produces a magnetic field that looks like a bar magnet. Increasing the current or the number of coils in the solenoid produces a stronger magnetic field.
- Magnetic Pole
- Area where the force is the strongest can be north or south. Like poles repel, while opposites attract. Magnets will always have both poles no matter how small you cut them.
- North Pole
- The geographic north pole is actually the south magnetic pole. Magnetic poles are named for the geograhic pole they try to find.
- Electric Motor
- A device that converts electrical energy to mechanical energy.
- Magnetic Forces
- Like poles repel each other while opposites attract each other.
- Electromagnet
- A strong magnet created when an iron core is inserted into the center of a current-carrying solenoid.
- Induced Magnetism
- When a piece of unmagnetised magnetic material touches or is brought near to the pole of a permanent magnet, it becomes a magnet itself.
- South Pole
- The geographic south pole is actually the north magnetic pole. Magnetic poles are named for the geograhic pole they try to find.
- Right Hand Rule
- Imagine holding the wire in your right hand. Your thumb points in the direction of the current. Your fingers wrap around in the direction of the magnetic field.