Electricity: Current Sophie Augustenborg, Alanna Depinto, Majok Ring

Key Terms Voltage- produces a flow of charge or current within a conductor Resistance- restrains the flow of current Power- the rate at which energy is transferred by electric currents

Flow of Charge Charge flows when there is a potential difference between the ends of a conductor To sustain a flow of charge in a conductor one end must be at a higher potential than the other

Electric Charge Electric current- the flow of electric charge Conduction Electrons carry the charge through the circuit Electric current is measured in amperes (A) An ampere is one coulomb of charge per second

Voltage Sources Voltage source is something that provides potential difference, such as batteries and generators. Generators convert mechanical energy to electrical energy

Voltage Sources A charge flows through a circuit and voltage flows across a circuit Voltage causes current

Electric Resistance The resistance of a wire depends on the conductivity of the material and the thickness and length of the wire Thick wires have less resistance than thin wires Longer wires have more resistance than shorter wires

Ohm’s Law Ohm’s Law: The current in a circuit is directly proportional to the voltage impressed across the circuit and inversely proportional to the resistance. Ohms (Ω) is the measure of electrical resistance

Resistance equation Resistance= Voltage/ Current R=V/I Ohm= volts/amps

Ohm’s Law If resistance is doubled the current will be halved

DC and AC Direct Current- a flow of charge that always flows in one direction Electrons always more from the negative terminal toward the positive terminal Alternating Current- electric current that repeatedly reversed direction

Power Electric power= Current x Voltage P= IV Watts= ampere(volts) 1 Kilowatt= 1000 watts 1 Kilowatt-hour= the amount of energy consumed in one hour a the rate of one kilowatt

Questions 1.How much current is drawn by a light bulb if it has a resistance of 1000 Ω when a voltage of 10 V is impressed across it? A. 10 AB..1 AC..01 AD. 100 A 2. If the electric power rating is 6500 watts and the voltage is 200 V what is the current? E AF AG. 1,300,000 AH. 13 A 3. What is the power rating of a lamp if the voltage is 10 V with a current of 160 A? A. 16 wattsB. 1.6 wattsC wattsD watts 4. If a calculator that operates on 10 V and.1 A is used for 1 hour how much energy does it use? E. 10 joulesF. 1 jouleG. 100 joulesH..1 joules 5. What is the current when a 50 watt lamp is connected to 100 V? A.

Questions 6. Electric potential difference is commonly called ______. E. VoltageF. CurrentG. ResistanceH. Ohms 7. Which offers more resistance to the flow of charge, a thick wire or a thin wire? A. Thick wireB. Thin WireC. Equal Resistance 8. How are voltage and current related? E. Voltage causes currentF. Current causes voltageG. They’re not related 9. What does a kilowatt hour measure? A. PowerB. CurrentC. VoltageD. Energy 10. When a lamp is plugged into a 100 V socket each coulomb of charge that flows in the current is raised to a potential energy of ______ joules. E. 10F. 20G. 100H. 1000

Answers 1.Current= 10 V/ 1000 Ω = (C).01 A watts= 200 V(A) = (E) 32.5 A 3.Power= 10 V (160 A) = (C) 1600 Watts 4.Power= 10 V (.1 A) = 1 Watt Energy= 1 watt (1 hour)= (G) 1 joule watts= current/ 100 V = (D) 5000 A

Answers 6. (E) Voltage 7. (B) Thin 8. (E) Voltage causes current 9. (D) Energy 10. (G) 100