# Shared Flashcard Set

## Details

DC
DC
17
Physics
11/14/2008

Term
 emf, &
Definition
 produces currentΔV = & - IRbattery is nearly constant voltage source but the small resistance reduces the voltage
Term
 Series (3)
Definition
 current stays the same, voltage splitsV = V1+V2+V3=IR1+IR2+IR3Req=R1+R2+R3
Term
 Parallel
Definition
 splits current, voltage stays the sameI=I1+I2+I3V/Req=V/R1+V/R2+V/R31/Req=1/R1+1/R2+1/R3
Term
 Kirchhoff's Rules:Junction RuleLoop Rule
Definition
 JR=sum of the currents entering equals sum fo currents leavingLR=sum of changes in potential around a closed loop is 0
Term
 Charging a battery: emfs in series and batteries lined up
Definition
 voltage = Σseparate voltages
Term
 Charging a battery: emfs in series and batteries not lined up
Definition
 total voltage = difference in voltages; lower voltage battery is charged
Term
 Charging a battery: emfs in parallel
Definition
 voltages must be the same
Term
 Capacitors in parallel (3)
Definition
 same voltage across each capacitorCeqV = C1V+C2V+C3V=(C1+C2+C3)VCeq=C1+C2+C3
Term
 Capacitors in series (3)
Definition
 all have the same chargeQ/Ceq=Q/C1+Q/C2+Q/C3=Q(1/C1+1/C2+1/C3)1/Ceq=1/C1+1/C2+1/C3
Term
 RC circuit in series
Definition
 capacitor charges when switch is closedvoltage and charge increases with time:VC=&(1-e-t/RC)Q=Q0(1-e-t/RC)
Term
 RC with no emf (2)
Definition
 capacitor dischargesQ=Q0e-t/RC
Term
 Electric hazards (3)
Definition
 even small currents are dangerous (10 mA)voltage can be lethal if you are wet and touching the groundsafest prongs are 3-pronged b/c they have a ground line
Term
 Ammeter (2)voltmeter (2)ohmmeter galvanometer (2)
Definition
 measures current, needs low resistance to not interfere with current, connect in series to measure resistancemeasures potential, should not effect voltage so resistance must be large, connect in parallel to measure resistancemeasures resistance, need a battery to produce current  deflection of needle is proportional to current flowing through it, uses torque to measure current
Term
 Source of emf
Definition
 transforms energy from some other form to electrical energy
Term
 Resistors in SeriesResistors in ParallelCapacitors in SeriesCapacitors in Parallel
Definition
 Req=R1+R2+R31/Req=1/R1+1/R2+1/R3 1/Ceq=1/C1+1/C2+1/C3Ceq=C1+C2+C3 1Pre, 1Sec
Term
 3 resistors, 4 Ω each, 4 scenarios and equivalent resistances
Definition
Term
 short circuit
Definition
 When part of a circuit with the most resistance is bypassed, and all of the current flows through the part with zero/negligible resistance
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