Download worksheet - Fullerland

Name: ______________________________________________________
Assigned on January 25, 2017
Electric Field Practice Problems
Electrostatics Unit
Directions: Use the information and the equations in the footer to complete the problems below on a separate sheet of paper. Show
your work (use the back of this page or a separate sheet if there is not enough room) and put all answers into scientific notation.
1. Suppose you are given an electric field but the charge that is producing the field is hidden. If all the field lines point into the hidden
region, what can you say about the sign of charge creating the field?
2. Draw the electric field lines between
a. Two positive point charges
b. A positive and a negative point charge
c. Two oppositely charged parallel plates (this would be a capacitor.. you can check your answer online)
3. A positive charge of 5x10–4 C is in another charge’s electric field. It experiences a force of 2.5x10–4 N to the left. What is the
magnitude and direction of the electric field at that point? (0.5 N/C left)
4. If you replaced the previous positive charge with one that is twice as large and placed it in the same spot in the same electric field
a. Would the new charge have the same size force acting on it?(No) Why?
b. Would you find the same size electric field?(yes) Why?
5. A negative charge of 2.0x10–8 C experiences a force of 0.06 N to the right in another charge’s electric field.
a. What is the field magnitude and direction at that point? (3x106 N/C left)
b. Can you positively tell if it’s a positive or a negative charge creating the field? (No) Why?
6. What is the magnitude of the electric field due to a 5.2x10-8 C charge at a point 0.038 m away? (3.2x105 N/C)
7. A tiny ball (mass = 0.024 kg) carries a charge of –21 C. What electric field (magnitude and direction) is needed to cause the ball
to float above the ground? (Hint: what pulls the ball down?) (11200 N/C)
8.
Each of two Van de Graaff generators, whose centers are separated from one another by 1.0 m, becomes charged after they are
switched on. One Van de Graff generator holds +3.0 C 10 -2 C while the other holds –2.0 X 10-2 C. What is the magnitude and
direction of the electric field halfway between them? (Draw a picture!) (1.8*109 N/C right)
9. April is decorating a tree in her backyard with plastic eggs in preparation for Easter. She hangs two eggs side by side so that their
centers are 0.40 m apart. April rubs the eggs to shine them up, and in doing so places a charge on each egg. The egg on the left
acquires a charge of 6.0 X 10-6 C while the egg on the right is charged with 4.0 X 10 -6 C. What is the electric field at a point 0.15
m to the right of the egg on the left? (DRAW a picture!) (1.8x106 N/C)