Magnetism
- Created by: SamFuller
- Created on: 12-10-18 17:41
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- Magnetism
- Poles
- Magnetic definition - Materials attracted by a magnet.
- Iron
- Zinc
- Nickel
- North-Seeking Pole definition - The end of a magnetic that points North
- South-seeking Pole - The end of a magnetic that points South
- Magnetism on Objects is the greatest near the poles
- Magnetic definition - Materials attracted by a magnet.
- Magnetic Fields
- Poles
- Magnetic definition - Materials attracted by a magnet.
- Iron
- Zinc
- Nickel
- North-Seeking Pole definition - The end of a magnetic that points North
- South-seeking Pole - The end of a magnetic that points South
- Magnetism on Objects is the greatest near the poles
- Magnetic definition - Materials attracted by a magnet.
- There is a Magnetic field around a magnet.
- There is an affect of magnetic materials and other magnets in this area
- There is an affect of magnetic materials and other magnets in this area
- It is convention to draw magnetic field lines coming from North to South
- Poles
- Permanent and induced Magnetism
- A permanent magnet produces its own magnetic field
- An induced magnet becomes magnetic when it is in a magnetic field
- The Magnetic field of a straight wire
- A current in a wire produces a magnetic field
- Right-hand grip rule: Line your thumb up with the direction of current. The way your hands curl gives you the magnetic field lines direction
- A cross shows current into the paper
- A dot shows cureen out of the paper
- Solenoids
- A long coil of wire which has a high combined Magnetic Field
- To increase the strength 1. Increase Current 2. More coils 3. Closer coils 4. Iron core in the centre
- Magnetic fllux density
- The number of lines of magnetic flux in a given area
- Force on a wire = magnetic flux density (teslas) x current x length
- A magnetic field acts on a wire to repel it.
- The size of the force depends on the flux density, the sixe of the current
- Left Hand rule: First finger pints in direction of field lines. Second finger points in direction of current. Thumb gives force direction
- Direct Current Motors
- A coil with a current on an axis in a magnet will rotate. This is because current is travelling in alternate directions on each side
- Kept rotating with a split-ring commutator
- A coil with a current on an axis in a magnet will rotate. This is because current is travelling in alternate directions on each side
- Induced P.D.
- When a wire moves through a Magnetic Field it induces a p.d.
- If the wire is in a creat circuit a current is induced
- Changing the direction of movement changes the direction of the p.d.
- This is the generator effect
- Induced P.D. with Coils
- Induced P.D.
- When a wire moves through a Magnetic Field it induces a p.d.
- If the wire is in a creat circuit a current is induced
- Changing the direction of movement changes the direction of the p.d.
- This is the generator effect
- Moving a magnet near a coil of wire induces a p.d.
- As the north pole moves towards the coil the current flows in a way the nearest pole becomes a north pole repelling the magnet
- As the magnet is repelled the direction of cuurent changes and the nearest pole becomes a south pole attracting the magnet back
- Induced P.D.
- Alternators
- 1. The coil is vertical. In this position the sides are parallel to the field and there is no p.d.
- 2. The coils is horizontal. The current cuts through the field at the greatest rate the induced p.d. is at its maximum
- 3. The coils is ertical again. There is no p.d.
- 4. The coils is horizontal again. The sides are opposite to 2. and so the p.d. is at the maximum in the alternate direction
- Poles
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