1. An insulated metal sphere, A, is charged to a value of +Q elementary charges. It is then touched and separated from an identical but neutral insulated metal sphere, B. This second sphere is then touched to a third identical and neutral insulated metal sphere C. Finally, spheres A and C are touched and then separated. Which of the following represents the distribution of charge on each sphere, respectively, after the above process has been completed?
(A) Q/3, Q/3, Q/3
(B) Q/4, Q/2, Q/4
(C) 3Q/8, Q/4, 3Q/8
(D) 3Q/8, Q/2, Q/4

2. A parallel-plate capacitor has a capacitance of C. If the area of the plates is doubled, while the separation between the plates is halved, the new capacitance will be
(A) 2C
(B) 4C
(C) C/2
(D) C

3. What is the capacitance of a parallel-plate capacitor made of two aluminum plates, 4 cm in length on a side and separated by 5 mm?
(A) 2.832 × 10⁻¹¹ F
(B) 2.832 × 10⁻¹⁰ F
(C) 2.832 × 10⁻¹² F
(D) 2.832 × 10⁻⁹ F

4. If 10 J of work is required to move 2 C of charge in a uniform electric field, the potential difference present is equal to
(A) 20 V
(B) 12 V
(C) 8 V
(D) 5 V

5. Which of the following diagrams represents the equipotential curves in the region between a positive point charge and a negatively charged parallel plate?

6. An electron is placed between two charged parallel plates as described below. Which of the following statements are true?

  I: The electrostatic force is greater at A than at B.
 II: The work done from A to B to C is the same as the work done from A to C.
III: The electrostatic force is the same at points A and C.
IV: The electric field strength decreases as the electron is repelled upward.

(A) I and II
(B) I and III
(C) II and III
(D) II and IV

7. How much kinetic energy is given to a doubly ionized helium atom due to a potential difference of 1,000 V?
(A) 3.2 × 10⁻¹⁶ eV
(B) 1,000 eV
(C) 2,000 eV
(D) 3.2 × 10⁻¹⁹ eV

8. Which of the following is equivalent to 1 F of capacitance?

9. An electron enters a uniform electric field between two parallel plates vertically separated with =400 N/C. The electron enters with an initial velocity of 4 × 10⁷ m/s. The length of each plate is 0.15 m.
(a) What is the acceleration of the electron?
(b) How long does the electron travel through the electric field?
(c) If it is assumed that the electron enters the field level with the top plate, which is negatively charged, what is the vertical displacement of the electron during that time?
(d) What is the magnitude of the velocity of the electron as it exits the field?

10. A 1-g cork sphere on a string is coated with silver paint. It is in equilibrium, making a 10° angle in a uniform electric field of 100 N/C as shown below. What is the charge on the sphere?

11. An electrostatically charged rod attracts a small, suspended sphere. What conclusions can you make about the charge on the suspended sphere?

12. Why is it safer to be inside a car during a lightning storm?