1. DC Circuits Review

2. If you compare a circuit to a river system, what represents the gravity that makes the water move? 1.Current 2.Wire 3.Resistance 4.Potential Difference 5.Power 6.Charge

3. If you compare a circuit to a river system, what represents the rate that the water flows in the river? 1.Current 2.Wire 3.Resistance 4.Potential Difference 5.Power 6.Charge

4. If you compare a circuit to a river system, what represents the boulders in the river? 1.Current 2.Wire 3.Resistance 4.Potential Difference 5.Power 6.Charge

5. If you compare a circuit to a river system, what represents the water molecules that are moving? 1.Current 2.Wire 3.Resistance 4.Potential Difference 5.Power 6.Charge

6. How is current affected if the number of electrons flowing in the circuit decreases? 1.The current increases. 2.The current decreases. 3.The current initially decreases and then is gradually restored. 4.The current is not affected.

7. A student connects six 1-ohm light bulbs in series to a 9-volt battery. What is the total circuit current? 1.0.67 amperes 2.1.5 amperes 3.9 amperes 4.54 amperes

8. The power used by a circuit can be found by: 1.using Ohm’s law. 2.dividing voltage by current. 3.adding all resistances. 4.multiplying voltage and current.

9. When electrons move through a metal conductor, 1.they move in a straight line through the conductor. 2.they move in zigzag patterns because of repeated collisions with the vibrating metal atoms. 3.the temperature of the conductor decreases. 4.they move at the speed of light in a vacuum.

10. In a conductor that carries a current, the drift velocity of an electron is 1.less than the average speed of the electron between collisions. 2.equal to the average speed of the electron between collisions. 3.greater than the average speed of the electron between collisions. 4.approximately equal to the speed of light.

11. Tripling the current in a circuit with constant resistance has the effect of changing the power by what factor? 1.2 2.3 3.9 4.27

12. Tripling the resistance in a circuit with constant voltage has the effect of multiplying the current by what factor? 1.3 2.9 3.1/3 4.1/9

13. When more devices are added to a series circuit, the total circuit resistance: 1.decreases. 2.increases. 3.stays the same. 4.may increase or decrease, depending on the device.

14. When more branches are added to a parallel circuit, the total circuit resistance: 1.decreases. 2.increases. 3.stays the same. 4.may increase or decrease, depending on the device.

15. In a series circuit, which of the following stays constant throughout the circuit. 1.Power 2.Resistance 3.Current 4.Voltage

16. In a series circuit, the total of which of the following will increase if another device is added to the circuit. 1.Power 2.Resistance 3.Current 4.Voltage

17. What is the device called that functions in series with a circuit as a safety device for excess current? 1.Rheostat 2.Potentiometer 3.Firewall 4.Breaker 5.Switch

18. If you add batteries to an existing circuit, which of the following will not increase? 1.Potential difference 2.Resistance 3.Current 4.All of them will increase