Unit+10+2016



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PRACTICE TEST CONCEPTUAL QUESTIONS


 * 1) How do batteries create a current? What causes current to flow? How is the current related to electron drift?
 * 2) What is voltage and/or voltage drop?
 * 3) Where do you measure current and voltage on a circuit (in general)? Why?
 * 4) When measuring current or voltage with the multimeter, why do you get a negative sign if you mix up the red and black leads?
 * 5) If electron drift is so slow (0.01 cm/s) why do devices turn on the instant you close the switch? If given the length of a circuit, could you calculate how long it takes for an electron starting at the - terminal to reach the + terminal?
 * 6) What is resistance and why does it cause heat? (think about resistance and electrical "friction"?)
 * 7) Why do short circuits cause an increase in current? Why could that be dangerous?
 * 8) Why are wire that are gauged for high current always bundles of smaller wires instead of just one thicker wire?
 * 9) How do fuse boxes and circuit breakers work? Why is one not used anymore?
 * 10) What is the difference between series and parallel circuits? How are current, resistance, and voltage drops affected when you add bulbs in each type?
 * 11) What are capacitors and how do they work? Why do they only provide current for a short amount of time? What three factors affect the quality of a capacitor?
 * 12) What is power and how do you calculate it?
 * 13) What is energy and how do you calculate it?
 * 14) On our electrical bills, are we paying for power or energy? How does the electrical company determine how much you owe?
 * 15) What is an RIV table, and how do you calculate them for series, parallel, and combination circuits?
 * 16) What is the difference between DC and AC current? Why does one transmit more power than the other?

PRACTICE TEST CALCULATION PROBLEMS


 * 1) Royal Electric Company charges $0.0975 per kilowatt-hour. Your hair krimper draws 120 volts at 1.5 amps and you use it for 30 minutes. How much does krimping your hair cost you?
 * 2) Energy efficient light bulbs are typically 12 W. Assuming your electric company charges $0.0975 per kilowatt hour and you use the bulb for approximately 4 hours a day, how much money do you save over a year? Assume a typical bulb is 60 W