Quiz, Chapter 17, 18

Student Last Name__________________________First Name_____________________9/24/2014

1. Two point charges are placed on the x axis as follows:
Charge q1 = 1 mC is located at x =  1 m, and charge q2 = 2 mC is at x = -3 m.
What are the magnitude and direction of the net force exerted by these two charges on a third charge q3 = -1  mC placed on the origin?

2. Charge q1 = 3 mC is located on the x axis at x =  -1 m, and charge q2 = 1 mC is located on the y axis at y = -0.5 m.
What are the magnitude, the x and y components, and the angle with the x direction of the net force exerted by these two charges on a third charge q3 =  1  mC placed on the origin?

3. A point charge of -4 nC is at the origin, and a second point charge of -1 nC is on the x axis at x = 6 m. Find the magnitude and direction of the  electric field at each of the following points on the x axis:
(a) x = 4 m,
(b) x = 12 m.

4. A point charge Q = 1 mC is held fixed at the origin. A second point charge q = 2 mC with mass of 1 kg is placed on the x axis , 1 m from the origin.
(a) What is  the electric potential energy U of the pair of charges?
(b) The second point charge is released from rest. What is its kinetic energy when its distance from  the origin is
(i) 2m;
(ii) 20 m;
(iii) 200 m.  

5. A 1 mF capacitor is connected to a power supply that keeps a constant potential difference of 1 V across the plates. A piece of material having a dielectric constant of 4 is placed between the plates, completely filling the space between them.
How mach energy is stored in the capacitor before and after the dielectric is inserted?