1. General Physics 2, Lec 3, By/ T.A. Eleyan 1 Additional Questions (Electric Field)

2. General Physics 2, Lec 3, By/ T.A. Eleyan 2 [1] Three point charges are arranged at the corners of a rectangle as shown in Fig. 1. If the net electric field at point P is in the y-direction, what is the relation between q1 and q2? A. q 2 = -0.8 q 1 B. q 2 = -0.7 q 1 C. q 2 = -0.5 q 1 D. q 2 = 0.7 q 1 E. q 2 = 0.8 q 1 [2] Four charges are arranged on the corners of a square as shown in Fig. 2 (a), (b), and (c). In which case(s) is the electric field equal to zero at the center of the square? Assume that all charges have the same magnitude and the only difference is the sign. A. a B. a and b C. b and c D. a and c E. a, b, and c

3. General Physics 2, Lec 3, By/ T.A. Eleyan 3 [3] A -1 C charge and a +2 C charge are placed on the x-axis as shown in Fig. 9. In which of the three labeled regions can the electric field be zero? A. Region I B. Region II C. Region III D. Regions II and III E. Regions I, II, and III [4] A 1 Coulomb charge is located at the origin. Another charge, Q, is located at x = 3 m. If the electric field is zero at x = 1 m, what is Q? A. -4 C B. -2 C C. 1.4 C D. 2 C E. 4 C

4. General Physics 2, Lec 3, By/ T.A. Eleyan 4 [5] Five charges are arranged in a pentagon as shown in Fig. What is the direction of the net electric field at the center of the pentagon? A. 54 degrees B. 126 degrees C. 198 degrees D. 270 degrees E. 342 degrees [6] A uniform electric field exists in the region between two oppositely charged plane parallel plates. An electron is released from rest at the surface of the negatively charged plate and strikes the surface of the opposite plate 2x10 -8 s later. If the magnitude of the electric field is 4x10 3 N/C, what is the separation between the plates? A. 3 cm B. 6 cm C. 7 cm D. 12 cm E. 14 cm

5. General Physics 2, Lec 3, By/ T.A. Eleyan 5 [7] A uniform electric field exists in a region between two oppositely charged plates. An electron is released from rest at the surface of the negatively charged plate and strikes the surface of the opposite plate, 2.0cm away, in a time 1.5*10 -8 s. (a) What is the speed of the electron as it strikes the second plate? (b) What is the magnitude of the electric field.

6. General Physics 2, Lec 3, By/ T.A. Eleyan 6 [8] Two point charges are a distance d apart. Find E points to the left P. Assume q1=+1.0*10 -6 C, q2=+3.0*10 -6 C, and d=10cm [9 ] Calculate E (direction and magnitude) at point P in Figure.

7. General Physics 2, Lec 3, By/ T.A. Eleyan 7 [10] A charged cord ball of mass 1g is suspended on a light string in the presence of a uniform electric field as in figure. When E=(3i+5j) *10 5 N/C, the ball is in equilibrium at q=37 o. Find (a) the charge on the ball and (b) the tension in the string.

8. General Physics 2, Lec 3, By/ T.A. Eleyan 8 [11] Find the electric field at point p in figure due to the charges shown. [12] The electric force on a point charge of 4.0mC at some point is 6.9*10-4N in the positive x direction. What is the value of the electric field at that point?

9. General Physics 2, Lec 3, By/ T.A. Eleyan 9 [13] In figure, two equal positive charges q=2x10 -6 C interact with a third charge Q=4x10 -6 C. Find the magnitude and direction of the electric field at Q.

10. General Physics 2, Lec 3, By/ T.A. Eleyan 10 [14] A small, 2.00-g plastic ball is suspended by a 20.0-cm-long string in a uniform electric field as shown in Figure. If the ball is in equilibrium when the string makes a 15.0° angle with the vertical, what is the net charge on the ball?