Physics Electrostatics

Transcription

1 Homework Procedure: Read pages specified in Honors Physics Essentials by Dan Fullerton. Questions labeled TQ will be questions about the text you read. These TQ s can be answered in one word, one phrase, or a complete sentence. Questions labeled CQ are conceptual questions and must be answered in complete sentences. Questions labeled QQ s are quantitative questions and the equation, substitution with units, and solve with units must be shown on your paper. CQ s and QQ s will be similar to the questions found in the Honors Physics Essentials textbook. Read Page 212 (Electric Charges) TQ1. What particles are inside the nucleus of an atom? Day 1 TQ2. What must an electron do to move to a higher energy level? TQ3. What is an atom called if it gains or loses an electron? TQ4. If it gains an electron, what kind of charge will it have? If it loses an electron, what kind of charge will it have? TQ5. What do like charges do with each other? What do unlike charge do with each other? TQ6. What is the symbol for charge? What are the units of charge? QQ7. An object possessing an excess of 8.0 x 10 6 electrons has what net charge? QQ8. What is the net electrical charge on an aluminum ion that is formed by losing three electrons? QQ9. How many electrons are present in a charge of -4.8 x C? Read Page 214 (Conductors and Insulators and Charging by Conduction) TQ10. Why are metals, such as gold, copper, and lead, good conductors? TQ11. What is one example of an insulator? TQ12. How does one charge an object by conduction? TQ13. In any scenario, what happens to the overall charge of a system? CQ14. If a conductor carrying a net charge of 14e is brought into contact with an identical conductor with no charge, what will be the charge on each conductor after they are separated? CQ15. If a conductor carrying a net charge of 8e is brought into contact with an identical conductor with a net charge of 12e, what will be the charge on each conductor after they are separated? QQ16. What is the net charge, in Coulombs, on each conductor in CQ15? CQ17. Since metals are great conductors, they are known to have a sea of electrons. What does this phrase mean practically? CQ18. If a positive conducting rod is brought near an electroscope, why do the leaves move apart?

2 Read Page 216 (Charging by Induction) Physics Electrostatics Day 2 TQ19. What does it mean to charge something by induction? CQ20. A negatively charged rod repels an unknown object. What is the relative net charge of the unknown object? CQ21. Which diagram best represents the charge distribution on the spheres x, y, and z when a negatively charged rod is brought near but does not touch them? Read Page 218 (Coulomb s Law) CQ22. What kind of electrostatic force is present when one positive and one negative charge come near each other? TQ23. What is the formula for Coulomb s Law? (Note: we will use k = 9 x 10 9 in our class) CQ24. Which graph best represents the relationship between the electrostatic force and the charge of an object? TQ25. If you were to quadruple (x4) the distance of two charges (keeping the magnitude of the charges the same), what would happen to the electrostatic force on a charge?

3 CQ26. Two charges are placed at a distance apart as shown below. One charge (the charge on top) has a charge of +3 x 10-6 C. The other charge (the one on the bottom) has a charge of +6 x 10-6 C. Which diagram best represents the electrostatic force vectors experienced by each charge? QQ27. One charge of q = +2.0 x 10-6 C is placed at a distance of 0.01 m away from another charge of q = -2.0 x 10-6 C. Calculate the electrostatic force between these two charges and indicate whether it is an attractive or repulsive force. QQ28. Two charges, each with a charge of q = +8.0 x 10-6, are placed at a distance of 0.05 m away from each other. Calculate the electrostatic force between these two charges and indicate whether it is an attractive or repulsive force. CQ29. Which graph best represents the relationship between the electric force between two charged particles and the distance between them? CQ30. Positively-charged alpha particles are fired through the region between two oppositely charged parallel plates in a cathode-ray tube as shown below. Which point (A, B, C, or D) best shows where the alpha particles are most likely to travel.

4 Day 3 Read Page (Electric Fields) TQ31. What is the equation for electric field strength, E? And what are the units? QQ32. What is the electric field strength of an electron that experiences an electric force of 8.0 x N? QQ33. If a proton is in an electric field of strength 4.0 x10-15 N/C, what electric force does it experience? CQ34. Draw the electric field lines for each case: (Draw at least 8 arrows for each case) (a) (b) CQ35. Show the direction of the net electric field in both cases at point P: (use an arrow and label E net )

5 Day 4 Read Page 226 and 228 (Electric Potential Difference and Parallel Plates) TQ36. What is the definition of electric potential difference or Voltage? QQ37. If an electron requires 8.0 x J of work to move it from point A to B, what is the potential difference? QQ38. If a 9 V battery passes x electrons each second, how much energy in Joules is present in this battery? TQ39. What is the equation for the electric field in terms of Voltage and distance? CQ40. Which graph best represents the potential difference (V) and the distance between two plates? CQ41. The electron is attracted to plate B. What is the sign of the charge on plate A as well as plate B? What is the direction of the electric field between the plates? CQ42. An electron beam is directed into a region of two oppositely charged parallel plates as shown below. Draw the direction of the electron beam inside of the parallel plates. Also, draw the electric field lines between the two parallel plates.