Chapter 24: Capacitance

1. Chapter 24: Capacitance Section 24-1: Capacitance

2. Two flat parallel plates are d = 0.40 cm apart. The potential difference between the plates is 360 V. The electric field at the point P at the center is approximately • 90 kN/C. • 180 N/C. • 0.9 kN/C. • Zero. • 3.6 ´ 105 N/C

3. Two flat parallel plates are d = 0.40 cm apart. The potential difference between the plates is 360 V. The electric field at the point P at the center is approximately • 90 kN/C. • 180 N/C. • 0.9 kN/C. • Zero. • 3.6 ´ 105 N/C

4. Two large metallic plates are parallel to each other and charged. The distance between the plates is d. The potential difference between the plates is V. The magnitude of the electric field E in the region between the plates and away from the edges is given by • d/V. • V2/d. • d ∙V. • V/d2. • V/d.

5. Two large metallic plates are parallel to each other and charged. The distance between the plates is d. The potential difference between the plates is V. The magnitude of the electric field E in the region between the plates and away from the edges is given by • d/V. • V2/d. • d ∙V. • V/d2. • V/d .

6. A capacitor of capacitance C holds a charge Q when the potential difference across the plates is V. If the charge Q on the plates is doubled to 2Q, • the capacitance becomes (1/2)V. • the capacitance becomes 2C. • the potential changes to (1/2)V. • the potential changes to 2V. • the potential does not change.

7. A capacitor of capacitance C holds a charge Q when the potential difference across the plates is V. If the charge Q on the plates is doubled to 2Q, • the capacitance becomes (1/2)V. • the capacitance becomes 2C. • the potential changes to (1/2)V. • the potential changes to 2V. • the potential does not change.

8. If a capacitor of capacitance 2.0 µF is given a charge of 1.0 mC, the potential difference across the capacitor is • 0.50 kV. • 2.0 V. • 2.0 µV. • 0.50 V. • None of these is correct.

9. If a capacitor of capacitance 2.0 µF is given a charge of 1.0 mC, the potential difference across the capacitor is • 0.50 kV. • 2.0 V. • 2.0 µV. • 0.50 V. • None of these is correct.

10. If the area of the plates of a parallel-plate capacitor is doubled, the capacitance is • not changed. • doubled. • halved. • increased by a factor of 4. • decreased by a factor of 1/4.

11. If the area of the plates of a parallel-plate capacitor is doubled, the capacitance is • not changed. • doubled. • halved. • increased by a factor of 4. • decreased by a factor of 1/4.

12. An 80-nF capacitor is charged to a potential of 500 V. How much charge accumulates on each plate of the capacitor? • 4.0 ´ 10–4 C • 4.0 ´ 10–5 C • 4.0 ´ 10–10 C • 1.6 ´ 10–10 C • 1.6 ´ 10–7 C

13. An 80-nF capacitor is charged to a potential of 500 V. How much charge accumulates on each plate of the capacitor? • 4.0 ´ 10–4 C • 4.0 ´ 10–5 C • 4.0 ´ 10–10 C • 1.6 ´ 10–10 C • 1.6 ´ 10–7 C

14. As the voltage in the circuit is increased (but not to the breakdown voltage), the capacitance • increases. • decreases. • does not change.

15. As the voltage in the circuit is increased (but not to the breakdown voltage), the capacitance • increases. • decreases. • does not change.

16. Doubling the potential difference across a capacitor • doubles its capacitance. • halves its capacitance. • quadruples the charge stored on the capacitor. • halves the charge stored on the capacitor. • does not change the capacitance of the capacitor.

17. Doubling the potential difference across a capacitor • doubles its capacitance. • halves its capacitance. • quadruples the charge stored on the capacitor. • halves the charge stored on the capacitor. • does not change the capacitance of the capacitor.

18. If the area of the plates of a parallel plate capacitor is halved and the separation between the plates tripled, then by what factor does the capacitance change? • It increases by a factor of 6. • It decreases by a factor of 2/3. • It decreases by a factor of 1/6. • It increases by a factor of 3/2. • It decreases by a factor of ½.

19. If the area of the plates of a parallel plate capacitor is halved and the separation between the plates tripled, then by what factor does the capacitance change? • It increases by a factor of 6. • It decreases by a factor of 2/3. • It decreases by a factor of 1/6. • It increases by a factor of 3/2. • It decreases by a factor of ½.

20. Chapter 24: Capacitance Section 24-2: The Storage of Electrical Energy

21. Which of the following statements is false? • In the process of charging a capacitor, an electric field is produced between its plates. • The work required to charge a capacitor can be thought of as the work required to create the electric field between its plates. • The energy density in the space between the plates of a capacitor is directly proportional to the first power of the electric field. • The potential difference between the plates of a capacitor is directly proportional to the electric field. • None of these is false.

22. Which of the following statements is false? • In the process of charging a capacitor, an electric field is produced between its plates. • The work required to charge a capacitor can be thought of as the work required to create the electric field between its plates. • The energy density in the space between the plates of a capacitor is directly proportional to the first power of the electric field. • The potential difference between the plates of a capacitor is directly proportional to the electric field. • None of these is false.

23. Which of the following statements about a parallel plate capacitor is false? • The two plates have equal charges of the same sign. • The capacitor stores charges on the plates. • The capacitance is proportional to the area of the plates. • The capacitance is inversely proportional to the separation between the plates. • A charged capacitor stores energy.

24. Which of the following statements about a parallel plate capacitor is false? • The two plates have equal charges of the same sign. • The capacitor stores charges on the plates. • The capacitance is proportional to the area of the plates. • The capacitance is inversely proportional to the separation between the plates. • A charged capacitor stores energy.

25. If you increase the charge on a parallel-plate capacitor from 3 µC to 9 µC and increase the plate separation from 1 mm to 3 mm, but keep all other properties the same, the energy stored in the capacitor changes by a factor of • 27. • 9. • 3. • 8. • 1/3.

26. If you increase the charge on a parallel-plate capacitor from 3 µC to 9 µC and increase the plate separation from 1 mm to 3 mm, but keep all other properties the same, the energy stored in the capacitor changes by a factor of • 27. • 9. • 3. • 8. • 1/3.

27. The energy stored in a capacitor is directly proportional to • the voltage across the capacitor. • the charge on the capacitor. • the reciprocal of the charge on the capacitor. • the square of the voltage across the capacitor. • None of these is correct.

28. The energy stored in a capacitor is directly proportional to • the voltage across the capacitor. • the charge on the capacitor. • the reciprocal of the charge on the capacitor. • the square of the voltage across the capacitor. • None of these is correct.

29. A parallel plate capacitor is constructed using two square metal sheets, each of side L = 10 cm. The plates are separated by a distance d = 2 mm and a voltage applied between the plates. The electric field strength within the plates is E = 4000 V/m. The energy stored in the capacitor is • 0.71 nJ. • 1.42 nJ. • 2.83 nJ. • 3.67 nJ. • Zero.

30. A parallel plate capacitor is constructed using two square metal sheets, each of side L = 10 cm. The plates are separated by a distance d = 2 mm and a voltage applied between the plates. The electric field strength within the plates is E = 4000 V/m. The energy stored in the capacitor is • 0.71 nJ. • 1.42 nJ. • 2.83 nJ. • 3.67 nJ. • Zero.

31. Chapter 24: Capacitance Section 24-3: Capacitors, Batteries and Circuits, and Concept Check 24-1

32. A circuit consists of a capacitor, a battery, and a switch, all connected in series. Initially, the switch is open and the capacitor is uncharged. The switch is then closed and the capacitor charges. While the capacitor is charging, how does the net charge within the battery change? • It increases. • It decreases. • It stays the same

33. A circuit consists of a capacitor, a battery, and a switch, all connected in series. Initially, the switch is open and the capacitor is uncharged. The switch is then closed and the capacitor charges. While the capacitor is charging, how does the net charge within the battery change? • It increases. • It decreases. • It stays the same

34. Several different capacitors are hooked across a DC battery in parallel. The charge on each capacitor is • directly proportional to its capacitance. • inversely proportional to its capacitance. • independent of its capacitance.

35. Several different capacitors are hooked across a DC battery in parallel. The charge on each capacitor is • directly proportional to its capacitance. • inversely proportional to its capacitance. • independent of its capacitance.

36. Several different capacitors are hooked across a DC battery in parallel. The voltage across each capacitor is • directly proportional to its capacitance. • inversely proportional to its capacitance. • independent of its capacitance.

37. Several different capacitors are hooked across a DC battery in parallel. The voltage across each capacitor is • directly proportional to its capacitance. • inversely proportional to its capacitance. • independent of its capacitance.

38. Several different capacitors are hooked across a DC battery in series. The charge on each capacitor is • directly proportional to its capacitance. • inversely proportional to its capacitance. • independent of its capacitance.

39. Several different capacitors are hooked across a DC battery in series. The charge on each capacitor is • directly proportional to its capacitance. • inversely proportional to its capacitance. • independent of its capacitance.

40. Several different capacitors are hooked across a DC battery in series. The voltage across each capacitor is • directly proportional to its capacitance. • inversely proportional to its capacitance. • independent of its capacitance.

41. Several different capacitors are hooked across a DC battery in series. The voltage across each capacitor is • directly proportional to its capacitance. • inversely proportional to its capacitance. • independent of its capacitance.

42. If C1 < C2 < C3 < C4 for the combination of capacitors shown, the equivalent capacitance is • less than C1. • more than C4. • between C1 and C4.

43. If C1 < C2 < C3 < C4 for the combination of capacitors shown, the equivalent capacitance is • less than C1. • more than C4. • between C1 and C4.

44. If C1 < C2 < C3 < C4 for the combination of capacitors shown, the equivalent capacitance is • less than C1. • more than C4. • between C1 and C4.

45. If C1 < C2 < C3 < C4 for the combination of capacitors shown, the equivalent capacitance is • less than C1. • more than C4. • between C1 and C4.

46. The equivalent capacitance of two capacitors in series is • the sum of their capacitances. • the sum of the reciprocals of their capacitances. • always greater than the larger of their capacitances. • always less than the smaller of the capacitances. • described by none of the above.

47. The equivalent capacitance of two capacitors in series is • the sum of their capacitances. • the sum of the reciprocals of their capacitances. • always greater than the larger of their capacitances. • always less than the smaller of the capacitances. • described by none of the above.

48. The equivalent capacitance of three capacitors in series is • the sum of their capacitances. • the sum of the reciprocals of their capacitances. • always greater than the larger of their capacitances. • always less than the smaller of the capacitances. • described by none of the above.

49. The equivalent capacitance of three capacitors in series is • the sum of their capacitances. • the sum of the reciprocals of their capacitances. • always greater than the larger of their capacitances. • always less than the smaller of the capacitances. • described by none of the above.

50. The equivalent capacitance of two capacitors in parallel is • the sum of the reciprocals of their capacitances. • the reciprocal of the sum of the reciprocals of their capacitances. • always greater than the larger of their capacitances. • always less than the smaller of the two capacitances. • described by none of the above.