# Shared Flashcard Set

## Details

Chapter 34: Electric Current Questions
Chapter 34: Electric Current Questions
32
Physics
01/15/2012

Term
 1. What is the name of the current that flows in one direction?
Definition
 DC Direct Current
Term
 2. What do we call current that flows back and forth?
Definition
 AC Alternating Current
Term
 3. What do we call the rate at which energy is transferred by electric current?
Definition
 Power
Term
 4. Temperature flows when there is a difference in temperature. Charge flows when there is a difference in ____________ potential.
Definition
 Voltage
Term
 5. What do we call the flow of electric charge?
Definition
 Electric current
Term
 6. What do we call electrons that carry the charge throughout the network?
Definition
 Conduction electrons
Term
 7. Electric current is measured _____ ___________.
Definition
 in amperes
Term
 8. What does the symbol A stand for?
Definition
 amperes
Term
 9. What is an ampere?
Definition
 The flow of 1 coulomb/second
Term
 10. What is the unit of charge?
Definition
 coulomb
Term
 11. Does a current-carrying wire have a net electric charge?
Definition
 No. The number of electrons entering one end is the same number of electrons leaving the other end.
Term
 12. In an electric circuit, what provides the potential difference, voltage source or electric pump?
Definition
 ? Dry cells or Wet cells → A battery is two or more cells, these are DC sourcesGenerators – AC source
Term
 13. What is the electric pressure across an average outlet?
Definition
 120 Volts
Term
 14. What does 120 volts mean? (I want extremely descriptive units)
Definition
 120 joules/coulomb. So each coulomb has 120 joules of energy
Term
 15. What does 120 joules mean? (I want extremely descriptive units)
Definition
 120 N•m. The force of 120 Newtons is exerted for 1 meter in the direction of flow.
Term
 16. The resistance of a material to the flow of electric current through it is measured in ______________________.
Definition
 ohms (symbol Ω)
Term
 17. More or Less. Thick wires have ________ resistance than thin wires.
Definition
 less
Term
 18. More or Less. Longer wires have ________ resistance than shorter wires.
Definition
 more
Term
 19. State Ohm’s Law, and then give me units for each symbol.
Definition
 I=V/R; amperes = volts/ohms
Term
 20. What causes electric shock in the human body – current or voltage.
Definition
 Current
Term
 21. Why don’t birds get electrocuted when they land on a high-voltage wire?
Definition
 The whole body is at one voltage. There is no difference in voltage across their body.
Term
 22. What portion of an appliance is connected to the ground wire?
Definition
 Outside surface of appliances are connected to the grounding prong of the plug.
Term
 23. What is the frequency of North American Alternating current?
Definition
 60 Hz, one cycle occurs every 1/60 sec
Term
 24. Name a tiny electronic device that restricts current to flow in a single direction in an electric circuit.
Definition
 diode
Term
 25. Do electrons move close to the speed of light when a circuit is completed?
Definition
 No, the electrons do not move as fast as the signal.
Term
 26. The rate at which electrical energy is converted into another form of energy (mechanical, heat, light) is called electric ________________.
Definition
 power
Term
 27. Give me an equation for electric power.
Definition
 . P=IV Power = current x voltage
Term
 28. What are the units of electric power?
Definition
 watt
Term
 29. What is the unit of watt?
Definition
 Joule/sec = N•m/sec
Term
 30. In a locality where energy costs 5 cents/kilowatt•hour, how much does it cost to burn a 100 watt light bulb for 24 hours?
Definition
 100 watt •(\$.05/kilowatt•hour)•(24 hours)•(1 kilowatt/1000watts) = \$.12
Term
 31. How much power is used by a calculator that operates on 8 volts and .1 amp? If it is used for 1 hour, how much energy does it use?
Definition
 P = IV = (.1amp)(8 volts) = .8 watts Energy is in kilowatt•hour so Energy = (.8 watts) (1 Hour) = .8 watts • hr = .0008 kilowatts• hour
Term
 32. What current will flow through a 1200 watt appliance operating on a 120 volt line?
Definition
 P = IV, 1200 watts = I (120 Volts); I = 10 amperes
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