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Electric currents

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## Electric currents

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**Electric currents**(Motion of electric charges) Physics 100 Chapt 13**Positive Ions**Atoms with one or more electrons removed _ _ + + + _ _ _ + + _ _ _ ”net” charge = +2qe**Battery**C Zn Zn - - + + Zn Zn++ Zn++ Zn - - - - Zn Zn + + - - Zn++ - - Zn Zn Zn++ + + acid**“Voltage”**Cathode Anode - + - - + + - - + + - E - + + - Zn++ - F + + W = Fd “Voltage” F = 2qeE d W0 2qe V W = 2qeEd W0 = 2qeE0d =E0d**Energy gained by the charge**W = Fd =Q E0d = QV F=QE0 F=QE0 Q Q Anode - + Cathode - E0 - + + - - + + Zn++ - - + + - Zn++ - + + d**Units again!**W = Q V joules joules coulomb W Q V = = Volt coulombs joule coulomb 1 V = 1**Continuous charge flow = “electric current”**Electrical “conductor” connected between anode & cathode Q Q Anode - + Cathode - - + + - - + + Zn++ - - + + - Zn++ - + +**electric current**Coulombs second Units: Q t I = =Amperes Q Q Anode - + Cathode - - + + - - + + Zn++ - - + + - Zn++ - + +**The conductor can be a piece of wire**Q t I = + + + Anode - + Cathode - - + + - - + + Zn++ - - + + - Zn++ - + +**The energy can be used to run a gadget**Energy time QV t P= = = I V + I + + I I Anode - + Cathode - - + + - - + + Zn++ - - + + - Zn++ - + +**Electric light**60 Watts I=? T Power = P = I V P V 60 W 100V I = = J/s J/C 1/s 1/C = 0.6 = 0.6 C s V=100V = 0.6 = 0.6 A**General circuit**I Appliance - + I + - 12V Energy source (device that separates + & - charge)**analogy**Amt of water flow ~ current appliance Height ~ voltage Pump ~ battery pump pond