physics q

Q

1. Draw a circuit that you can use to test whether or not something conducts electricity. Explain how to interpret the test results. (If this happens, then …)

2. What evidence do you have showing that charge flows in the opposite direction during capacitor charging from the flow direction when it is being discharged?

3. What evidence do you have that charge flows in a single “forward” direction in a single loop circuit?

4. What evidence do you have that electric currents create magnetic fields?

5. (3 pts) We did an experiment that showed differences in the ability of different capacitors to store energy. Two different tests pointed to the same result (that the silver capacitors stored more energy than the blue capacitors. Explain how each test showed a difference, and state which test was more convincing.

6. What evidence have you gotten that there is indeed no conducting path through the interior of a properly functioning capacitor?

7. (A) At the left below, draw a circuit that

will charge an uncharged capacitor. (B) At the right below, draw a circuit that will

discharge a charged capacitor.

Bulb 1 Lit or unlit

Bulb 2 Lit or unlit

Bulb 3Lit or unlit

8. (3 pts) Draw the unambiguous continuous conducting path through the circuit drawn at the right and indicate whether each bulb is lit or unlit.

9. If you light a bulb using the hand crank generator, how can you make the bulb light even brighter?

10. Consider a water pipe that has a flow of 9 gallons per minute that branches into two smaller pipes. If one of the smaller pipes carries 4 gallons per minute, how much water flows through the other small pipe.

11. Will an incandescent light bulb with a thin filament draw more current or less current than a bulb with a thinner filament when connected to the same voltage source?

12 . Are automobile headlights connected in series, in parallel, or something else?

13. Dr. Johnson has said that some types of evidence are better than others. Rank these types of evidence from the best to the worst.

(A) Four groups out of 6 reported the same result.

(B) A person who works in the field of what is being studied tells you what the answer is.

(C) Every time the experiment is performed, the result is the same.

Best_____________________________________Worst.

14. How is alternating current different from direct current?

15. Does your cell phone use ac or dc when you are driving around town?

16. How much current flows through a 10 W resistor when it is connected across a 12 V battery?

17. It was mentioned in class that electrons moving through a wire have two different types of speeds. One is related to their temperature, and the other is related to the value of the electric current in the wire. Which type is faster?

18. How much power does a ceiling fan use if it is connected to 120 V and draws 0.50 A?

19. Suppose you have an unmarked capacitor that resembles neither the blue capacitor or the silver capacitor. Using only the things that we had and used in class, what experiment could you do to determine its capacitance relative to one of the aforementioned capacitors? Describe the experiment and how you would be able to know which has the larger capacitance.

20. In the air analogy for capacitor circuits, what do the following items represent?

(A) Air hose _____

(B) Air pump

(C) Air

21. In a circuit with batteries, wires, and light bulbs, does the charge that lights the bulbs start moving from the batteries?

22. In a circuit with batteries, wires, light bulbs and a capacitor, the bulbs light for a short time then go out. Does that mean that charge can briefly go through the capacitor before it has a chance to stop it?

23. Each of the light bulbs in the figure at the right are identical, and each of the batteries in the figure are also identical. Each figure has an ammeter in the circuit (indicated with the letter “A”. Rank the currents measured in each figure from the smallest to the largest (or state why you cannot).

Smallest current Largest current.

24. Carefully trace the unambiguous continuous conducting path in the

circuit shown and indicate whether each bulb is lit or unlit.

Bulb 1_______________ Bulb 2 ________________