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Magnets and Magnetic Fields. Ch 21.1. Magnetic Forces. The force a magnet exerts on Another magnet Iron or similar metal Moving charges Magnetic Fields Region where force is strongest North and South. Magnetic Fields. Surrounds a magnet and exerts a magnetic force
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Magnets and Magnetic Fields Ch 21.1
Magnetic Forces • The force a magnet exerts on • Another magnet • Iron or similar metal • Moving charges • Magnetic Fields • Region where force is strongest • North and South
Magnetic Fields • Surrounds a magnet and exerts a magnetic force • Strongest near the poles • Attracts or repels other magnets
Magnetic Fields Around Magnets Around Earth • Earth is giant magnet • Magnetosphere
Magnetic Materials • Magnetic Domains • Large # of atoms • Aligned magnetic fields • Ferromagnetic Materials • Can be magnetized due to domains
Magnetic Materials Nonmagnetized Magnetized • Domains arranged randomly • Domains arranged in an order
Electromagnetism Ch. 21.2
Electricity and Magnetism • Electromagnetic Force • Electric force = charged particles • Magnetic force = movement of electrons
Electricity and Magnetism MF Around Moving Charges Forces Acting on Moving Charges • Moving electric fields create a magnetic fields • Charge will be deflected in a direction perpendicular to the magnetic field and velocity of charge
Solenoids and Electromagnets • Solenoid • Coil of current carrying wire that produces a magnetic field • Electromagnet • Solenoid with a ferromagnetic core • Changing the current in an electromagnet controls the strength and direction of its magnetic field
Electromagnetic Devices • Change electrical energy into mechanical energy • 1. Galvanometer • Uses solenoid • 2. Electric Motors • Uses electromagnets • 3. Loudspeakers • Uses solenoid
Generating Electric Current • Electromagnetic Induction • Generating current by moving an electrical conductor relative to a magnetic field • Discovered by Faraday • Voltage is induced in a conductor by a changing magnetic field
Generator • Device converts mechanical energy into electrical by rotating a coil of wire in a magnetic field
Generators AC DC • Produces alternating current • Produces direct current
Transformers • Device that increases or decreases voltage and current of 2 linked AC circuits • Changes the magnetic field in 1 coil then induces an AC current in a nearby coil with a different # of turns
Transformers Step Down Step Up • Decreases voltage and current • Increases voltage • Decreases current
Energy in your Home • Generated by coal, water, nuclear, wind natural gas, and petroleum • Turbines • Fanlike blades that turn when pushed