1. A charge of -5.0nC is placed at the origin. A second particle of charge 5.0nC is placed a distance of 1cm along the positive y-axis. What is the force on the -5.0 nC particle? (a) -(2.2 10-2 N) (b) (2.2 10-2 N) (c) -(2.2 10-3 N) ! (d) (2.2 10-3 N) (e) -(2.2 10-2 N) 2. Three charges of 5.0nC are placed on three of the corners of a square of side length d=2cm. Find the magnitude of the electric field at the fourth corner of the square. (a) 1.710! N/C (b) . N/C (c) 1.510!! N/C (d) 1.110!! N/C (d) 7.610!! N/C 3. Three particles of charge 10.0nC are placed on the vertices of an equilateral triangle with side length 2cm. Find the electric field in the center of the triangle. (a) 1.710! N/C (b) 1.410! N/C (c) 1.910! N/C (d) 2.910! N/C (e) 0 N/C 4. Three particles of charge 10.0nC are placed on three of the corners of a square of side length d=2cm. Find the magnitude of the electric field at the center of the square. (a) . N/C (b) 4.510!! N/C (c) 1.710! N/C (d) 1.710!! N/C (e) 0 N/C

5. A rod of length L=1cm and linear charge density 2.0 nC/cm is placed along the y-axis with its center at the origin, as shown in the figure. Find the magnitude of the electric field a distance 5.0cm along the y-axis.

(a) . N/C (b) 7.2610! N/C (c) 7.2610!! N/C (d) 7.2610! N/C (e) 7.2610! N/C 6. A rod of length L=1cm and linear charge density 2.0 nC/cm is placed along the y-axis with its center at the origin. Find the magnitude of the electric field a distance 1.0cm along the x axis. (a) . N/C (b) 1.310! N/C (c) 1.310!" N/C (d) 3.510! N/C (e) 13 N/C 7. An infinite rod with charge density 0.1C/m is placed at the origin and oriented with the z-axis. A 0.2C charge is placed a distance 1m along the positive x-axis. Find the force on the rod. (a) 3.610! N (b) 1.810! N (c) 1.810! N (d).! N (e) 0 N 8. A sphere of radius 2 cm has uniform charge density 0.01 C/cm3. Find the total charge of the sphere. (a) 0.08C (b) 0.34C (c) 0.50C (d) 0.02C (e) 0.01C

9. An electron is placed in an electric field pointing along the positive x-axis. Which direction does the electron move.

(a) Along the positive x direction (right) (b) Along the negative x direction (left) (c) Along the positive y direction (up) (d) Along the negative y direction (down) 10. A dipole made up of a positive charge 3.0nC and a negative charge -3.0nC is placed in an electric field of magnitude 1.0 N/C. What is the magnitude of the net force on the dipole?

(a) 0 N (b) 1 N (c) 2 N (d) 3 N (e) 4 N

11. A dipole made up of a positive charge 3.0 nC and a negative charge -3.0 nC is placed in an electric field of magnitude 1.0 N/C. Which direction does the dipole rotate?

(a) clockwise (b) counterclockwise (c) it does not rotate 12. Two infinite charged plates with surface charge density and - are separated by a distance d. The magnitude of the electric field between the charged plates is (a) /(2 ) (b) /(2 !) (c) /(4!) (d) 0 (e) / 13. Three parallel, infinite charged plates of charge density , each separated by a distance d from the last, are placed in the xy-plane. Find the magnitude of the electric field between the second and third plates. (a) /(2 ) (b) /( ) (c) /(4!) (d) 3 /(2 !) (e) /! 14. When two point charges are a distance d part, the electric force that each one feels from the other has magnitude F. In order to make this force half as strong, the distance would have to be changed to: (a) / (b) 2 (c) the distance does not have to be changed (d) /2 (e) 2

15. A charge Q is located a short distance from a second charge -2Q. The force on charge Q has magnitude F. Find the distance between the charges. (a) 2!/ (b) !/ (c) / (d) / ! (e) / ! 16. A charge Q is located a short distance from a second charge -2Q. The force on charge Q has magnitude F. If the magnitude of both charges are doubled, the force on charge Q becomes: (a) 1 F (b) 2 F (c) 3 F (d) 4 F (e) 5 F 17. Two charges +15nC are placed at the ends of a spring with spring constant k=1 N/m. How far apart are the two charges? (a) 0.5cm (b) 15cm (c) 1.3cm (d) 2cm (e) 8cm 18. Two charges Q are placed at the ends of a spring with spring constant k. In equilibrium, the distance between charges is d. If the charges Q are doubled, what does the distance between the charges change to? (a) 1.4d (b) 2d (c) 4d (d) 1.6d (e) 1.26d 19. A 2.0nC charge with mass 1kg is sitting above an infinite, uniformly charged plate, in the xy-plane, with charge density =0.1C/m2. Find the acceleration of the charge. (g=9.8m/s2) (a) +1.5 m/s2 (b) +0.5 m/s2 (b) +0.5 m/s2 (b) -0.5 m/s2 (b) -1.5 m/s2

20. A charge Q with mass 1kg is sitting above an infinite, uniformly charged plate, in the xy-plane, with charge density =0.1C/m2. What charge would the mass need in order to experience zero net force? (g=9.8m/s2) (a) There is no such charge (b) -2.5nC (d) -1.7nC (d) 1.7nC (e) 2.5nC