Q1) Choose the INCORRECT statement:
1) Gauss' law can be derived from Coulomb's law
2) Gauss' law states that the net number of lines crossing any closed
surface in an outward direction is proportional to the net charge enclosed
within the surface
3) Coulomb's law can be derived from Gauss' law and symmetry
4) Gauss' law applies to a closed surface of any shape
5) According to Gauss' law, if a closed surface encloses no charge, then
the electric field must vanish everywhere on the surface
Q2) The figure below shows a Gaussian cube of face area A
immersed in a uniform electric field E that points in the +z
direction. In terms of E and A, what is the flux through (a) the
front face (in the xy plane), (b) the rear face, (c) the whole cube?
1) (a) +EA (b) +EA (c) +2EA
2) (a) +EA (b) -EA (c) 0
3) (a) -EA (b) -EA (c) –2EA
4) (a) -EA (b) +EA (c) 0
5) none of the above
Q3) A charged point particle is placed at the center of a spherical
Gaussian surface. The electric flux E is changed if:
1) the sphere is replaced by a cube of the same volume
2) the sphere is replaced by a cube of one-tenth the volume
3) the point charge is moved off center (but still inside the original
sphere)
4) the point charge is moved to just outside the sphere
5) a second point charge is placed just outside the sphere
Q4) A cylindrical piece of
insulating material is placed in an
external electric field, as shown.
The net electric flux passing
through the surface of the
cylinder is
1) positive
2) negative
3) zero
Q5) Two open surfaces are in an electric field as shown. Surface
A is a flat circular disk of radius R, which squarely faces the
charge. Surface B is a hollow-cup hemisphere of the same radius
R. The flat rim of the hemisphere is the
same distance from the charge as the rim
of the flat disk. Which surface has the
A
greater flux through it?
B
1) A
2) B
3) Both have the same flux.
Q6) Two open surfaces are in an electric
field as shown. Surface A is a flat circular
disk of radius R. Surface B is a hollow-cup
hemisphere of the same radius R. Which
surface has the greater flux through it?
1) A
2) B
3) Both surfaces have the same flux.
A
B
Q7) The electric flux through a sphere of radius r surrounding a
point charge q is F. The electric flux through a sphere of radius 2r
surrounding the same point charge is _______.
1) F/4
2) F
3) 2F
4) 4F
Q8) A point particle with charge q is placed inside a cube but not
at its center. The electric flux through any one side of the cube is
1) zero
2) q/o
3) q/4o
4) q/6o
5) cannot be computed using Gauss' law
Q9) Rank the closed surfaces shown in
increasing order of electric flux.
1)
2)
3)
4)
A<B<C
C<B<A
B<C<A
A=C<B
Q10) In the figure below, a full Gaussian surface encloses two of the four
positively charged particles. (a) Which of the particles contribute to the
electric field at point P on the surface? (b) Which net flux of electric field
through the surface is greater (if either): that due to q1 and q2 or that due to
all four charges?
1)
2)
3)
4)
5)
(a) all four
(a) all four
(a) all four
(a) q1 and q2
(a) q1 and q2
(b) neither (they are equal)
(b) q1 and q2
(b) q3 and q4
(b) q1 and q2
(b) neither (they are equal)
Q11) A point charge causes an electric flux of –100 Nm2/C
to pass through a spherical Gaussian surface of radius 10 cm.
If the radius of the Gaussian surface were doubled, how
much flux would pass through the surface?
1) –25 Nm2/C
4) –200 Nm2/C
2) –50 Nm2/C
5) –400 Nm2/C
3) –100 Nm2/C
Q12) There is a certain net flux i through a Gaussian sphere of
radius r enclosing an isolated charged particle. Suppose the
enclosing Gaussian surface is changed to a larger Gaussian sphere
of radius 2r. Is the net flux through the new Gaussian sphere
greater than, less than, or equal to i?
1) greater than
2) less than
3) equal to
Q13) The non-zero electric field everywhere on a closed surface is

constant: E  constant. Is the following calculation correct?
 
 E  da  E  da  EA
1) Definitely correct
2) Definitely incorrect

3) It depends on details of the surface and E .
Q14) Which one of the following statements is true concerning the
strength of the electric field between two oppositely charged
parallel plates?
1) It is zero midway between the plates.
2) It is a maximum midway between the plates.
3) It is a maximum near the positively charged plate.
4) It is a maximum near the negatively charged plate.
5) It is constant between the plates except near the edges.
Q15) The figure shows sections of two infinite, parallel,
nonconducting sheets with surface charge densities +4 and
-6. What is the magnitude and direction of the electric field
at points (a) above the top sheet and (b) between the sheets?
1) (a) 5/0 down (b) /0 down
2) (a) 5/0 down (b) 5/0 up
3) (a) /0 down (b) 5/0 down
4) (a) /0 down (b) 5/0 up
5) (a) /0 down (b) /0 down
+4
-6
Q16) The electric charge per unit area is +for plate 1 and –for plate 2.
The magnitude of the electric field associated with plate 1 is /o, and the
electric field lines for this
plate are as shown. When the
two are placed parallel to one
another, the magnitude of the
electric field is
1) 2/o between, 0 outside.
2) 2/o between, ±/o outside.
3) zero both between and outside.
4) ±/o both between and outside.
5) none of the above.
Q17) Two large insulating parallel plates carry charge of equal
magnitude, one positive and the other negative, that is distributed
uniformly over their inner surfaces. Rank the points 1 through 5
according to the magnitude of the electric field at the points, least
to greatest.
1) 1, 2, 3, 4, 5
2) 2, then 1, 3, and 4 tied, then 5
3) 1, 4, and 5 tie, then 2 and 3 tie
4) 2 and 3 tie, then 1 and 4 tie, then 5
5) 2 and 3 tie, then 1, 4, and 5 tie
Q18) Two large parallel plates carry positive charge of equal
magnitude that is distributed uniformly over their inner surfaces.
Rank the points 1 through 5 according to the magnitude of the
electric field at the points, least to greatest.
1) 1, 2, 3, 4, 5
2) 5, 4, 3, 2, 1
3) 1, 4, and 5 tie, then 2 and 3 tie
4) 2 and 3 tie, then 1 and 4 tie, then 5
5) 2 and 3 tie, then 1, 4, and 5 tie
Q19) A solid insulating sphere of radius R contains positive charge
that is distributed with a volume charge density that does not
depend on angle but does increase with distance from the sphere
center. Which of the graphs below might give the magnitude E of
the electric field as a function of the distance r from the center of
the sphere?
Q20) Which of the following graphs represents the magnitude of
the electric field as a function of the distance from the center of a
solid charged conducting sphere of radius R?
Q21) A point charge q = +30e is inside a conducting shell of
charge –10e as shown in the figure below. How is the charge
on the conducting shell distributed?
1) –10e on inner surface
2) –10e on outer surface
3) –10e evenly distributed throughout shell
4) –30e on inner surface, +20e on outer surface
5) –30e on inner surface, -20e on outer surface
q
Q22) A negative point charge with charge -Q sits in the interior of
a spherical metal shell. The conducting metal shell has no net
charge. What is the total charge on the inner surface of the shell?
inner surface
1) –Q
2) +Q
3) +2Q
4) zero
5) Some other answer.
outer surface
-
gaussian
surface
Q23) A negative point charge with charge -Q sits in the interior of a
spherical metal shell. The conducting metal shell has no net charge.
What is the total charge on the exterior surface of the shell?
inner surface
1) –Q
2) +Q
3) +2Q
4) zero
5) Some other answer.
outer surface
-
gaussian
surface
Q24) A spherical conducting shell has charge Q. A particle with
charge q is placed at the center of the cavity. The charge on the
inner surface of the shell and the charge on the outer surface of
the shell, respectively, are:
1) 0, Q
2) q, Q - q
3) Q, 0
4) -q, Q + q
5) -q, 0
Q25) A charge of +3μC is at the center of a hollow neutral
conductor (neutral means has a charge of 0 μC). What are the
charges on the inner and outer surfaces of the conductor?
1) Inner surface 0 μC, outer surface 0 μC
2) Inner -3 μC, outer 3 μC
3) Inner -3 μC, outer 4 μC
4) Inner 0, outer 3 μC
5) Inner -3 μC, outer 0 μC
Q26) A ball of charge -50e lies at the center of a hollow spherical
metal shell that has a net charge of -100e. What is the charge on
(a) the shell's inner surface and (b) its outer surface?
1) (a) –50e (b) –100e
2) (a) +50e (b) +150e
3) (a) +50e (b) –100e
4) (a) 0e (b) –150e
5) none of the above
Q27) A solid, conducting sphere of radius a carries an excess charge
of +6 μC. This sphere is located at the center of a hollow, conducting
sphere with an inner radius of b and an outer radius of c as shown.
The hollow sphere also carries a total excess charge of +6 μC.
Determine the excess charge on the inner surface of the outer sphere
(a distance b from the center of the system).
1) zero coulombs
2) –6 μC
3) +6 μC
4) +12 μC
5) –12 μC
Q28) A solid, conducting sphere of radius a carries an excess charge
of +6 μC. This sphere is located at the center of a hollow, conducting
sphere with an inner radius of b and an outer radius of c as shown.
The hollow sphere also carries a total excess charge of +6 μC.
Determine the excess charge on the outer surface of the outer sphere
(a distance c from the center of the system).
1) zero coulombs
2) –6 μC
3) +6 μC
4) +12 μC
5) –12 μC
Q29) Which one of the following figures shows a qualitatively
accurate sketch of the electric field lines in and around this
system?
Q30) Which one of the following statements is true concerning the excess
charge on a conductor?
1) It is evenly distributed throughout the entire conductor.
2) It is distributed throughout the entire conductor and it is distributed
according to the object’s shape.
3) It is only on the surface of the conductor and is evenly distributed.
4) It is only on the surface of the conductor and it is distributed according
to the shape of the conductor.
Q31) A spherical shell with a uniform positive charge density on
its surface is near a positive point charge. Is the electric field
inside the sphere zero?
+
+
+
+
1) E=0 inside
2) E  0 inside
3) Not enough info to answer.
+
+
E=?
+
+
+
+
+
+
+