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Clayton State University
Department of Natural Sciences
August 25, 2014
Physics 2212 – Quiz 1
Name __SOLUTION___________________________________
1. Which of the following statements are true? Check all that apply.
a. Electric charge is conserved.
b. A positive charge and a negative charge attract each other.
c. A neutral object contains no charge carriers.
d. Electric charge is quantized.
e. Two positive charges attract each other.
f. Two negative charges repel each other.
2.
A rubber object receives a negative charge
by rubbing it with a fur. In the rubbing process, have electrons been added to the
object or have protons been removed from it?
A. Electrons have been added.
B.
B. Protons have been removed.
3. Three objects are brought close to each other, two at a time. When objects A and B are
brought together, they repel. When objects B and C are brought together, they also repel.
Which of the following are true? (Select all that apply.)

a. One object is neutral.
b. Objects A and C possess charges of the same sign.
c. Objects A and C possess charges of opposite sign.
d. Additional experiments must be performed to determine the signs of the charges.
e. All three objects possess charges of the same sign.
Clayton State University
Department of Natural Sciences
September 3, 2014
Physics 2212 – Quiz 2
Name __SOLUTION___________________________________
Charge Q1=6.00 nC is at (0.300 m, 0), charge Q2=−1.00 nC is at (0, 0.100 m), and
charge Q3=5.00 nC is at (-0.400 m, 0). What is the magnitude of the net electric field at
the origin? Specify both magnitude and direction. (Note, the charges in the picture are
mislabeled, the solution is based on the statement above and NOT on the picture).
E1  ke
q1
 5.99  10 2 N / C
2
r1
@ 180o
E2  k e
q2
 8.99 10 2 N / C
2
r2
@ 90o
E3  k e
q3
 2.8110 2 N / C
2
r3
@ 0o
E1x  5.99  10 2 N / C
E1 y  0
E2 x  0
E2 y  8.99  10 2 N / C
E3 x  2.8110 2 N / C
E3 y  0
ETOTx  E1x  E2 x  E3 x  3.18  10 2 N / C
ETOTy  E1 y  E2 y  E3 y  8.99  10 2 N / C
ETOT  ETOTx  ETOTy  9.54  10 2 N / C
2
2
  110o
Department of Natural Sciences
September 15, 2014
Physics 2212 – Quiz 3
Name __SOLUTION___________________________________
A flat sheet is in the shape of a rectangle with sides of lengths 0.400 m and 0.600 m. The
sheet is immersed in a uniform electric field of magnitude 73.9 N/C that is directed at
20∘ from the plane of the sheet. Find the electric flux through the sheet.
 
 E  E  A  (73.9 N / c)(0.400 m)(0.600 m) cos(70o )  6.06 Nm 2 / C
2. The three small spheres shown in the figure carry charges q1 = 4.35 nC, q2 = -7.50 nC,
and q3 = 2.30 nC. Find the net electric flux through the closed surface S5 shown in cross
section in the figure.
E 
qencl
0
 96.0 Nm 2 / C
3.
In the figure, a uniform electric field is shown passing through a flat area A. In (a), the
surface of area A is perpendicular to the electric field. In (b), the surface is tilted by an
angle θ with respect to the electric field. In (c), the surface is parallel to the electric field.
In which orientation is the electric flux through the surface the equal to zero?
a. The electric flux is zero through all of the surfaces shown.
b. The electric flux is the zero through the surface shown in (b).
c. The electric flux is nonzero and equal through all of the surfaces shown.
d. The electric flux is the zero through the surface shown in (a).
e. The electric flux is the zero through the surface shown in (c).