1. |
What is the purpose of the electric field in a circuit? |
2. |
What is an electronVolt (ev) a measure of? |
3. |
A charge pops out of an 9 volt battery and travels through an electrical circuit. How much energy does the charge lose by the time it reaches the other side of the circuit? |
4. |
How much energy did the charged particle, in the previous problem, have when it first popped out of the battery? |
5. |
Why do physicists choose to model current as the flow of positive charges instead of negative? |
6. |
What is the formula for calculating the current in terms of charge and time? |
7. |
What are the S.I. units of each quantity in the previous problem? |
8. |
Define "resistance." |
9. |
What is S.I. symbol for resistance? |
10. |
Define "resistivity." |
11. |
What happens to the resistance of a wire if it is made wider? |
12. |
A lamp sits 16 feet from a wall outlet. The wire on the lamp is 6 feet long. Which extension cord would be the best choice or does it matter? A slender 12 foot long; a slender 20 foot long; A wider diameter 12 foot long, or a wider diameter 20 foot. |
13. |
Most wires in extension cords are made from copper. What is the ratio of change in resistance of an extension cord if the temperature changes from -5 °C to 28 °C? (This ratio is defined as R/R_{o}) |
14. |
A piece of aluminum is at 30°C and has a resistance of 100 Ω. If the aluminum is immersed in liquid nitrogen at -196°C, then what is the new resistance of this piece of aluminum? |
15. |
Define "ohmic device." |
16. |
Define Ohm's Law |
17. |
What are the S.I. units in Ohm's Law? |
18. |
How much voltage is used by a clock that is plugged in to a wall? |
19. |
Draw a small graph of a d.c. power source. |
20. |
Draw a small graph of an a.c. power source. |
21. |
What type of power comes out of a wall outlet, a.c. or d.c.? |
22. |
What is the equation for power that is also used to describe how quickly mechanical energy is used up? |
23. |
What is the S.I. unit for power? |
24. |
What is a thermal energy loss? |
25. |
When looking a battery package, what units are used by manufacturers to describe the charge stored in a battery? |
26. |
Explain why the unit in the previous question equal the concept of charge? |
27. |
A lawn mower battery is rated at 6.0 Ah's. If the lights on the lawn mower are powered solely by this battery and "die" in 1.5 hours. Then how much current is being drawn from the battery? |
28. |
How should batteries be connected to increase battery life? |
29. |
The cost of electricity in California averages about $0.16/kWh. (In Virginia it is about $0.10/kWh.) How much power does a toaster use in California if is costs $0.01 to cook toast in a time of 4 minutes? |