Test 3 Review

Today and tomorrow we are reviewing for Test 3, which will cover mirrors, lenses, ray diagrams, and electrostatics. In addition to the review problems below, look back at bellworks, in-class activities, and homeworks. Especially these:

Lens ray diagrams
Mirror ray diagrams
The human eye
Static electricity
Coulomb's Law

From the book:
p. 478
15. a. What condition must exist for a converging lens to produce a virtual image?
b. What condition must exist for a diverging lens to produce a real image?
16. How could you demonstrate that an image was indeed a real image?
21. This problem asks you to draw ray diagrams to find the images created by three lenses. You will have to get these from the textbook.
p. 515
7. a. how do like charges behave?
b. How do unlike charges behave?
9. a. If electrons are rubber from cat's fur onto a rubber rod, does the rod become positively or negatively charged?
b. How about the cat's fur?
10. What does it mean to say that charge is conserved?
27. By how much is the electrical force between a pair of ions reduced when their separation distance is doubled? Tripled?
28.If you scuff electrons from your hair onto a comb, are you positively or negatively charged? How about the comb?
31. If a glass rod that is rubbed with a plastic dry cleaner's bag acquires a certain charge, why does the plastic bag have exactly the same amount of opposite charge?
35. The five thousand billion billion freely moving electrons in a penny repel one another. Why don't they fly out of the penny?
p. 529
14. Clearly distinguish between electrical potential energy and electric potential.
16. The SI unit for electrical potential energy is the joule. What is the SI unit for electric potential?
27. Is it correct to say that an object with twice the electric potential of another has twice the electrical potential energy? Defend your answer.