Ch.22-CURRENT ELECTRICITY

CURRENT A flow of charged particles – electric current. A river of electrical energy that moves through a wire Must have a closed continuous loop to work Charges flow from higher potential difference to lower

Terms to Know: Current Battery Resistance Ammeter Voltmeter number of charges that travel per second Battery voltage (source) Resistance impedes current uses energy Ammeter measures current Voltmeter measure voltage  measured in Amperes Amps or A measured in Volts Volts or V  measured in Ohms ohms (W) measures Amps measures Volts Terms to Know:

SCHEMATICS A sketch of what the circuit looks like Represents how the current will flow in the circuit Specific types of symbols for sketches p. 597

Simple electric circuit shown pictorially and schematically.

OHM’S LAW Ohm defined how current(amps), voltage(volts), and resistance(ohms=W) relate V = I R V : voltage of battery (e.g. 9 V battery) I : current (number of charges per second) R : resistance (e.g. light bulb, stereo, etc.)

Remember: Power is energy per time (P=E/t) P = I2 R = V2/ R = I V P : power (Watts) I : current (Amps) R : resistance (W) V : voltage (Volts) Remember: Power is energy per time (P=E/t)

Practice Problems Total of FIVE problems p594 #1-5  pick one p600 #12 & 14 or #13 & 14  pick one or the other (2 problems) p603 #23-25  pick one Total of FIVE problems

CIRCUITS PARALLEL SERIES current has multiple paths to follow broken circuit may not stop electrical flow voltage is the same through each resistor current adds for each SERIES current has only one path to follow broken circuit stops all flow of electricity current is the same through each resistor voltage adds for each http://www.regentsprep.org/Regents/physics/phys03/bparcir/default.htm http://www.regentsprep.org/Regents/physics/phys03/bsercir/default.htm

CH 22 HW 61. 18 Watts; 16200 J 64. 0.5 Amps; 9 Volts, 4.5 Watts; 1.6x104 J 65. 960 Watts 73. 120 Volts 79. 300 W; 60 W; 2 Amps 82. $513/kWh 92. 3 Amps; 12 Amps; when it is on

Ch.23: Series and Parallel Circuits

Review: SCHEMATICS A sketch of what the circuit looks like Represents how the current will flow in the circuit Specific types of symbols for sketches p. 597

Review: CIRCUITS PARALLEL SERIES current has multiple paths to follow broken circuit may not stop electrical flow voltage is the same through each resistor current adds for each SERIES current has only one path to follow broken circuit stops all flow of electricity current is the same through each resistor voltage adds for each http://www.regentsprep.org/Regents/physics/phys03/bparcir/default.htm http://www.regentsprep.org/Regents/physics/phys03/bsercir/default.htm

Review: OHM’S LAW Ohm defined how current(amps), voltage(volts), and resistance(ohms=W) relate V = I R V : voltage of battery (e.g. 9 V battery) I : current (number of charges per second) R : resistance (e.g. light bulb, stereo, etc.)

CIRCUITS PARALLEL current has multiple paths to follow 1/Requivalent = 1/R1 + 1/R2 voltage is the same Vtotal = V1 = V2 Voltmeters only current adds for each Itotal = I1 + I2 SERIES current has only one path to follow Requivalent = R1 + R2 voltage adds for each Vtotal = V1 + V2 current is the same Itotal = I1 = I2 Ammeters only http://www.regentsprep.org/Regents/physics/phys03/bparcir/default.htm http://www.regentsprep.org/Regents/physics/phys03/bsercir/default.htm

58. 11.8 kW 59. 404 W 62. 37 W; 7.4 Volts; .88 Watts; 1.48 Watts 64. 27 W; 1.7 Amps; 37 & 7.7 Volts; 63 & 13 Watts 67. 10 W; 50 W; 19 Amps; 5.5 Amps; 2.2 Amps; 11 Amps 71. 225 W; 13 W; 3.6 Watts 73. 8.89 W;4.5 Amps; 2.5 Amps CH 23 HW 61. 18 Watts; 16200 J 64. 0.5 Amps; 9 Volts, 4.5 Watts; 1.6x104 J 65. 960 Watts 73. 120 Volts 79. 300 W; 60 W; 2 Amps 82. $513/kWh 92. 3 Amps; 12 Amps; part b CH 22 HW

CIRCUITS LAB MATERIALS: OBJECTIVE: Switches Light bulbs Batteries Wires OBJECTIVE: Determine the difference between the schematic and effects of series and parallel circuits

PROCEDURES Connect the battery, one bulb, a switch together How bright is the bulb? Repeat for the other bulb Connect the battery, switch, and two bulbs in series How bright are the bulbs? PROCEDURES Connect the battery, switch, and two bulbs in parallel How bright are they?

SCHEMATICS Go back and draw a schematic for each set-up (4 drawings) Remember that a schematic is not how it looks to us, but what the current sees It helps to understand where the current is going Be sure to use the proper symbols!!