1. Check answers – a few were found to be wrong…possibly reword the definition/law questions

2. Electrostatics JEOPARDY

3. Powell 100 Williams BrownHeadAugustine 200 300 400 500 100 200 300 400 500 200 300 400 500 200 300 400 500

4. A Balloons X, Y and Z are hanging as shown. Balloon X is positively- charged Balloon Y ____. Amust be positively- charged Dcould be either negatively-charged or neutral Bmust be negatively- charged Ecould be either positively-charged or neutral Cmust be neutral

5. What is D. could be either negatively-charged or neutral ?

6. The charge an electrophorus would gain if the base was made out of glass. A

7. What is Negative ?

8. The reason that scraps of paper jump up and down and back up when a charged plastic rod is brought near. A

9. What is The pieces become polarized, are attracted to the rod, and jump up. When they touch, the charge is transferred to the piece, giving it the same charge. The attraction stops. When it touches ground, it looses its charge, allowing it to become polarized again ?

10. Explanation of the basic process of charging an electroscope. A

11. What is A charged object is touched to the ball of the electroscope. The charges are transferred and travel across the bars of the scope, causing it to repel ?

12. Explanation of how one’s hair raises when you touch the Van de Graaff generator. A

13. What is Negative charges travel from the Van de Graaff generator onto one’s body as they try to get as they try to spread out. When on your hair, they cause it to raise up as they try to repel as far as possible ?

14. The magnitude of the force of a +25µC charge on a -50µC charge 20 cm away. A +25µC-50µC 22cm

15. 9x10 9 (50 x 10 -6 C)(25 x 10 -6 C) Nm 2 C2C2 (.20 m) 2 What is 2.81 x 10 2 N ? =2.81 x 10 2 N F = k Q 1 Q 2 r2r2

16. The magnitude of the force 10 electrons would apply on 4 protons at a distance of 1µm. A Hint…q e =1.6x10 -19 C

17. What is 9.22 x 10 -15 N ? 9x10 9 [10(1.6 x 10 -19 C)] Nm 2 C2C2 (1 x 10 -6 m) 2 [4(1.6 x 10 -19 C)] = 9.22 x 10 -15 N F = k Q 1 Q 2 r2r2

18. The force applied on the farthest right charge by the other two charges. A +8µC-6µC 7mm3mm +5µC

19. 9x10 9 (8 x 10 -6 C)(5 x 10 -6 C) Nm 2 C2C2 (10 x 10 -3 m) 2 =3.6 x 10 3 N What is 2.64 x 10 4 N left ? 9x10 9 (6 x 10 -6 C)(5 x 10 -6 C) Nm 2 C2C2 (3 x 10 -3 m) 2 =3 x 10 4 N F 13 = F 23 = F 23 + F 13 = 2.64 x 10 4 left F = k Q 1 Q 2 r2r2

20. The number of electrons you would need to put on electrostatic flying boots to make a 70kg person hover at a height of 2 m above a charge of -50 mC. A Ahhh.. I’m flying!

21. What is 2.38 x 10 12 ? F = 70kg (9.81 m/s 2 ) = 9x10 9 (-50 x 10 -3 C)[n(-1.6 x 10 -19 C)] Nm 2 C2C2 (.20 m) 2 n = 2.38 x 10 12 F = k Q 1 Q 2 r2r2

22. The force on the orange charge. A +4.6 C -5.4 C +4.6 C -5.4 C 5 m 4 m 2.5 m 2 m + 7.2 C

23. What is 0 N ? Diagonal forces cancel each other out, resulting in a net force of 0N on the orange charge. F = k Q 1 Q 2 r2r2

24. No net electric charge can be created or destroyed. A

25. What is The law of conservation of electric charge ?

26. +1.6 x 10 -19 C A

27. What is The Charge of a proton ?

28. The charging of an isolated conducting object by grounding it while a charged body is nearby. A

29. What is Induction ?

30. The force F exerted on a tiny positive test charge placed divided by the magnitude of the test charge. A

31. What is Electric Field, E ? E = F q

32. Two equally charged charge that have the opposite charge. A

33. What is A dipole ?

34. A The charge of the orange charge Followed by The charge of the blue charge

35. What is Positive (orange), negative (blue) ?

36. A |Q|=4.7 x 10 -4 C Charge on the blue charge

37. What is -3.5 x 10 -4 C ? 4.7 x 10 -4 C ? = 8 lines 6 lines |Q|=4.7 x 10 -4 C

38. A The number of lines that should point outwards from the orange plate. BE CAREFUL!!!! ? ?

39. What is 0 ? Follow up question How many lines should point inwards? 8 lines 8 charges = ? 6 charges

40. A Charges of point charges in order (orange, blue, green, white)

41. What is - - + + ? Orange Blue Green White

42. Minimum of 2 errors in the following drawing, with explanations of error. A 2 C

43. What are Wrong direction of field lines (should go from positive to negative) and Wrong number of field lines (should be equal as charge is equal) ?

44. E-Field at X below A 12 C 15m

45. What is 6 x 10 8 N/C left ? 12 C 15m 9x10 9 (12 C) Nm 2 C2C2 (15 m) 2 =6 x 10 8 N/C E = k Q r2r2

46. A Approximate location of E=0 N/C on line between orange and blue charge 12 C 15m 24 C

47. What is Somewhere between orange and mid point (7.5m to the right of orange) ? 12 C 15m 24 C E = k Q r2r2

48. The E-Field at the X A 12 C 15m 24 C 10 m

49. What is 2.33 x 10 9 N/C right ? E = k Q r2r2 12 C 15m 24 C 10 m E 24C E 12C 9x10 9 (12 C) Nm 2 C2C2 (25 m) 2 =1.7 x 10 8 N/C 9x10 9 (24 C) Nm 2 C2C2 (10 m) 2 =2.16 x 10 9 N/C

50. The letter which denotes the location with the greatest magnitude of E-Field A A B C D 1m 4m 3m 2m Q=1.5C Q=24CQ=18CQ=7C

51. What is C ? E = k Q r2r2 E A = k (1.5C) (1m) 2 =1.5k C/m 2 E B = k (24C) (4m) 2 =1.5k C/m 2 E C = k (18C) (3m) 2 =2k C/m 2 E D = k (7C) (2m) 2 =1.75k C/m 2

52. A The E-Field at the orange point. -4 C -5 C +4 C -5 C 5 m 2.5 m

53. 3.53m=r E = k Q r2r2 9x10 9 (4 C) Nm 2 C2C2 (3.53 m) 2 =2.89 x 10 9 N What is 5.77 x 10 9 N 45 degrees N of W ?

55. FINAL JEOPARDY The complete process for charging an electrophorus using proper terminology. (5 minutes)

56. TIE BREAKER WHAT IS THE SIGNIFICANCE OF THE CATEGORY TITLES?

57. 2004 Illini Basketball Starters (when we should have won the NCAA tourney)