1. A lightning bolt transfers 22 C of charge to the earth. How many electrons are transferred from this one bolt?

The earth is struck by an average of 100 lightning bolts each second. How many electrons pour into the earth each second from lightning?

2. How far apart are two protons if they exert a force of 0.5 N on each other?

3. Two electrons in bulk matter are an angstrom (1 x 10-10 m) apart. What electrostatic force do they exert on each other?

4. One point charge has a magnitude of 5.4 x 10-7 C. A second charge that is 0.25 m away has a magnitude of 1.1 x 10-17 C. What is the electric force magnitude of one charge on the other?

5. A piece of styrofoam has a charge of 0.002 mC and is placed 0.5 m from a grain of salt with a charge of 0.03 nC. How much electrostatic force is produced?

6. A charged object has 82 protons, 82 neutrons, and 109 electrons. What is its overall charge? (Be sure to include the sign.)

7. In order to collect weather data on a remote island, you decide to send a weather balloon to the location. You attach a 1 C charged object to the balloon and plan to propel it to the island using electrostatic force. Given the balloon's size and the standard wind patterns en route, you will need to overcome an opposing air resistance of up to 100 N at any point on the balloon's journey. How much charge will you need to propel the 1 C balloon from your location to the island 750 km away, considering the opposing wind? Ignore the curvature of the earth.

8. A metal sphere as a charge of +2.3 x 10-6C and lies 2 meters away from another metal sphere of unknown charge. If the attractive force present between the spheres is 0.05 N, what is the charge on the second sphere?

9. Four electrons are each located on the corners of a square, with the sides of the square measuring 1 m long. What is the total force (magnitude and direction) exerted on one of the electrons by the other three?

1. For a source charge Q and a test charge q separated by a distance r, the electric potential energy of the test charge is kQq / r. If two alpha particles (each with two protons and two neutrons) are 0.5 m apart, what is the electric potential energy of the system?

2. Two protons approach each other from very far away with an initial speed of 500 m/s. How close do they come to each other before turning around?

3. A 4 V battery is connected to two parallel plates that are separated by a distance of 0.25 mm. Find the magnitude of the electric field created between the plates.

4. A proton starts moving from rest in an electric field of magnitude 6.5x10 5

V/m. The field points in the positive

x-direction, and under the influence of the field, the proton moves 0.25 m in that direction. a. What is the change in the proton's electric potential as a result of the displacement? b. What is the change in the proton's electric potential energy due to the displacement? c. What is the speed of the proton after it has moved 0.25 m, beginning from rest?

5. If 3 C of charge moves through a 12 V potential difference, what is the change in electric potential energy?

6. An electric field of constant strength 6 N/C points in the positive y-direction. A proton moves from the origin to the point (0, 2) m. What is the change in the proton's electric potential? What would be the change in electric potential if an electron moved the same way?

7. A particle with a charge 1.7 nC moves along an electric field line in a field of strength 35 N/m. If the particle moves 19 m along the line, what is the change in its electric potential and electric potential energy?

8. A -3 C charge moves through a 2000 V loss of electric potential. Will the charge gain or lose electric potential energy? Will the charge gain or lose kinetic energy?

9. Find the total electric potential energy of the system of charges shown below:

1.1 nc 4 m 3 nc 2 m - - 4.5 m 8 nC