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Unit 9 |
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Electricity & Magnetism |
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A “build-up” of electric charge |
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Charged particles from the atom |
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protons (positive) |
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electrons (negative) |
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1 e- = 1.6 x10-19
Coulombs |
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Like charges repel |
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Unlike charges attract |
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Work per unit of charge required to move a
charged particle against the electric field. |
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Measured in volts. |
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1 volt = 1 joule/coulomb |
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The rate of flow of electric charge. |
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Measured in amps. |
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1 Amp = 1 coulomb /second |
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The opposition to the flow of electric charge. |
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Depends on the type of material, the diameter,
the length and the temperature. |
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Measured in ohms (W) |
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A single path for current to follow |
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Alternate paths for current to follow |
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The rate of using energy or doing work. |
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Measured in watts (W) |
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The ability of a material to attract
ferrous(iron) materials. |
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Magnetic materials: iron, cobalt, nickel |
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Polarity |
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Magnetic fields |
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Geographic north vs magnetic north |
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An electric current will produce a magnetic
field. |
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Right- hand rule (conventional current) |
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Left hand rule (electron flow) |
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Electromagnets |
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Electromagnetic induction - a moving magnetic
field will produce an electric current in a loop of wire. (It is also
possible to move the loop of wire in a magnetic field to produce current.) |
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Motors |
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Generators |
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Transformers |
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Switches |
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telephones |
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Notes