Magnetism

magnetic metals

• Iron

• Cobalt

• Nickel

nonmagnetic metals:

• gold

• copper

• magnesium

Dynamo effect:

using electromagnetic induction to generate electricity using energy from KE stores

Dynamo effect test:

• connect ammeter to conductor and moving electrical conductor thru mag field (magnets) or opposite will show magnitude + direction of induced current (Ammeter)

Generator:

• rotate a coil in a mag field

• like a motor but slip rings instead so don’t switch (AC)

• faster data on CRO produce more peaks and voltage

Investigating magnetic fields:

1. place magnet on paper and draw a dot at edge of magnet

2. place a compass w/edge on the dot and draw another dot on the opposite needle edge

3. remove and repeat process

4. connect the dots and this reflects the mag field shape

DC Motor:

• Coil in between magnets and connected to split rings

• carbon brushes attached to a cell touch split ring commutators

• split ring commutators switch after every 180 keeping the rotation in the same direction

Loud speaker:

• AC electrical signals from amplifier fed to coil of wire

• consists of coil of wire around permanent magnet

• AC cause a force + change mag field direction

• coil oscillates = sound waves