1. See also the NOTES documents posted online at our wikispace, the online self-quizzes posted at our wikispace, and all assignments and materials related to our Neuron Action Potential Circuit Design Challenge Lab (especially your Lab Reflection) and your Ohm’s Law and Electric Power Practice Problems Classwork

2. Electricity is generated by the movement of charged particles, in which like charges ___________ one another and opposite charges _________ one another. a) repel, repel b) repel, attract c) attract, repel d) repel, repel

3. Electricity is generated by the movement of charged particles, in which like charges ___________ one another and opposite charges _________ one another. a) repel, repel b) repel, attract c) attract, repel d) repel, repel

4. Electric charge is measured in ________________ Electric current is measured in _______________ Electric power is measured in ________________ Electric resistance is measured in _____________ Electric potential difference is measured in ________.

5. Electric charge is measured in Coulombs Electric current is measured in amperes Electric power is measured in watts Electric resistance is measured in ohms (Ω) Electric potential difference is measured in volts.

6. How is electric power calculated? Provide 1. The a mathematical equation in words, _________________________________ 2. The a mathematical equation in one letter symbols, _________________________________ 3. And the mathematical equation in units. _________________________________

7. How is electric power calculated? Provide 1. The a mathematical equation in words, Power = Current X Voltage 2. The a mathematical equation in one letter symbols, P= IV 3. And the mathematical equation in units. watts = amperes X volts

8. What is Ohm’s Law? Provide 1. The a mathematical equation in words, _________________________________ 2. The a mathematical equation in one letter symbols, _________________________________ 3. And the mathematical equation in units. _________________________________

9. What is Ohm’s Law? Provide 1. The a mathematical equation in words, Volts = Current X Resistance 2. The a mathematical equation in one letter symbols, V= IR 3. And the mathematical equation in units. volts = amperes X ohms

10. In a battery-powered circuit, because they have a _______ charge, electrons flow from the ______ to the ______. a) positive; anode; cathode b) positive; cathode ; anode c) negative; anode; cathode d) negative; cathode ; anode

11. In a battery-powered circuit, because they have a _______ charge, electrons flow from the ______ to the ______. a) positive; anode; cathode b) positive; cathode ; anode c) negative; anode; cathode d) negative; cathode ; anode

12. According to Ohm’s Law, if resistance between two points increases, current will: a) decrease b) increase c) remain the same. d) become zero.

13. According to Ohm’s Law, if resistance between two points increases, current will: a) decrease b) increase c) remain the same. d) become zero.

14. A circuit in which the path is complete, with no gaps is called a(n) _________________ because the _________ can flow. a) open circuit, current b) open wire, resistance c) closed circuit, current d) closed system, resistance

15. A circuit in which the path is complete, with no gaps is called a(n) _________________ because the _________ can flow. a) open circuit, current b) open wire, resistance c) closed circuit, current d) closed system, resistance

16. Imagine a simple series circuit with one 1.5V battery and one bulb. When the 1.5V battery is replaced with a 3V battery a) the bulb gets brighter b) the bulb gets dimmer c) the bulb stays at the same level of brightness

17. Imagine a simple series circuit with one 1.5V battery and one bulb. When the 1.5V battery is replaced with a 3V battery a) the bulb gets brighter b) the bulb gets dimmer c) the bulb stays at the same level of brightness

18. In a given circuit, increasing the length of the wire has which effect? a) Increases resistance b) Decreases resistance c) Increases current d) Has no affect on resistance or current e) B and C

19. In a given circuit, increasing the length of the wire has which effect? a) Increases resistance b) Decreases resistance c) Increases current d) Has no affect on resistance or current e) B and C

20. How much power is used by a 9-V battery that produces a 3 amp current?

21. How much power is used by a 9-V battery that produces a 3 amp current? Remember, P= IV ; or watts = amperes X volts. Thus, in this case, watts = 3 amperes X 9 Volts = 27 watts

22. A circuit in which the path has gaps is called a(n) _________________ and the current __________ flow. a) open wire, can b) open circuit, cannot c) closed circuit, can d) closed system, cannot

23. A circuit in which the path has gaps is called a(n) _________________ and the current __________ flow. a) open wire, can b) open circuit, cannot c) closed circuit, can d) closed system, cannot

24. In a given circuit, decreasing the temperature of the wire has which effect? a) Increases resistance b) Decreases resistance c) Increases current d) Has no affect on resistance or current e) B and C

25. In a given circuit, decreasing the temperature of the wire has which effect? a) Increases resistance b) Decreases resistance c) Increases current d) Has no affect on resistance or current e) B and C

26. According to Ohm’s Law, if electric potential difference between two points increases, current will: a) decrease b) increase c) remain the same. d) become zero.

27. According to Ohm’s Law, if electric potential difference between two points increases, current will: a) decrease b) increase c) remain the same. d) become zero.

28. You have two light bulbs, one with a rating of 50 watts and one with a rating of 100 watts. Remember that the voltage across each would be the same if they were placed in a light socket. How would the current through each light bulb compare? a) Both bulbs would draw the same current. b) The higher watt bulb would draw less current. c) The lower watt bulb would draw less current. d) The lower watt bulb would draw more current.

29. You have two light bulbs, one with a rating of 50 watts and one with a rating of 100 watts. Remember that the voltage across each would be the same if they were placed in a light socket. How would the current through each light bulb compare? a) Both bulbs would draw the same current. b) The higher watt bulb would draw less current. c) The lower watt bulb would draw less current. d) The lower watt bulb would draw more current.

30. How much power is used when a 3 V battery produces 0.1 amp of current?

31. How much power is used when a 3 V battery produces 0.1 amp of current? Remember, P= IV ; or watts = amperes X volts. Thus, in this case, watts = 0.1 amperes X 3 volts, = 0.3 watts

32. Current is measured in _____, resistance in measured in _____ and power is measured in _____. a) watts, ohms, amperes b) amperes, ohms, watts c) Coulombs, volts, amperes d) ohms, amperes, watts e) amperes, ohms, Coulombs

33. Current is measured in _____, resistance in measured in _____ and power is measured in _____. a) watts, ohms, amperes b) amperes, ohms, watts c) Coulombs, volts, amperes d) ohms, amperes, watts e) amperes, ohms, Coulombs

34. In a given circuit, increasing the diameter of the wire has which effect? a) Increases resistance b) Decreases resistance c) Increases current d) Has no affect on resistance or current e) B and C

35. In a given circuit, increasing the diameter of the wire has which effect? a) Increases resistance b) Decreases resistance c) Increases current d) Has no affect on resistance or current e) B and C

36. What is the resistance of a device if the current through it is 10 amps and the voltage across it is 5 volts?

37. Remember, V= IR ; or volts = amperes X ohms Therefore, R = V ; or ohms = volts. I amperes Thus, in this case, ohms = 5 volts = 0.5 ohms 10 amperes

38. Label the circuit below to show the following: anode, battery, cathode, direction of electron flow, resistor, and switch. LED light (0.40 Amp, 2.6 Volts)

39. Label the circuit below to show the following: anode, battery, cathode, direction of electron flow, resistor, and switch. LED light (0.40 Amp, 2.6 Volts) Battery Anode Cathode Electron flow Switch Resistor Electron flow

40. What power is used if a resistance of 100 ohms has a current of 0.1 amps flowing through it?

41. What power is used if a resistance of 100 ohms has a current of 0.1 amps flowing through it? Remember, P= IV ; or watts = amperes X volts Here we must first determine the volts before we can solve for watts. From Ohm’s Law, we know that V= IR ; or volts = amperes X ohms Thus, in this case, volts = 0.1 amps X 100 ohms = 10 volts. Substituting this value in our power equation above gives: watts = 0.1 amperes X 10 volts = 1 watt

42. What is the power used in a device if the resistance is 100 ohms and the voltage across it is 4V?

43. Remember, P= IV ; or watts = amperes X volts Here we must first determine the amperes before we can solve for watts. From Ohm’s Law, we know that V= IR ; or volts = amperes X ohms. Rearranging this equation gives: amperes = volts ohms Thus, in this case, amperes = 4 volts =.04 amperes 100 ohms Substituting this value in our power equation above gives: watts = 0.04 amperes X 4 volts =.16 watts