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ame: ________________________ Class: ___________________ Date: __________
Exam 1--PHYS 102--S14
Multiple Choice
Identify the choice that best completes the statement or answers the question.
1. The magnitude of the charge on an electron is
approximately:
a. 10-23 C
b. 10-19 C
c. 1019 C
d. 1023 C
e. 109 C
2. When you charge an object by induction, you...
a. touch the ball with a charged object.
b. move electrons from your finger to the ball.
c. induct the ball with charge.
d. bring a charged object near but do not touch
the ball.
3. An electrical insulator is a material:
a. must be a crystal
b. that has more electrons than protons on its
surface
c. cannot be a pure chemical element
d. through which electrons do not flow easily
e. containing no electrons
4. The diagram shows two pairs of heavily charged plastic cubes. Cubes 1 and 2 attract each
other and cubes 1 and 3 repel each other.
Which of the following illustrates the forces of cube 2 on cube 3 and cube 3 on cube 2?
a. A
d. D
b. B
e. E
c. C
5. In which of the following diagrams is the potential along the x-axis equal to zero?
a.
b.
c.
a
b
c
d.
e.
none of these
all of these
1
ame: ________________________
9. Two identical charges, 2.0m apart, exert forces of
magnitude 4.0 N on each other. The value
of either charge is:
6. Two uncharged metal spheres, L and M, are in
contact. A positively charged rod is brought
close to L, but not touching it, as shown. The two
spheres are slightly separated and the rod
is then withdrawn. As a result:
a. both spheres are neutral
b. both spheres are positive
c. both spheres are negative
d. L is negative and M is positive
e. L is positive and M is negative
7. Two small charged objects attract each other with a
force F when separated by a distance
d. If the charge on each object is reduced to
one-fourth of its original value and the distance
between them is reduced to d/2 the force becomes:
a. 3.8x105 C
b. 1.8x10-9 C
c. 4.2x10-5 C
d. 1.9x105 C
e. 2.1x10-5 C
10. Consider this arrangement of charges, which are at
the vertices of an equilateral triangle (ie. they are
all equidistant from one another). Which of the
arrows best represents the direction of the net force
on the +4q charge?
a. F/16
b. F/8
c. F/4
d. F/2
e. F
8. Two particles, X and Y, are 4m apart. X has a
charge of 2Q and Y has a charge of Q. The
force of X on Y:
a.
b.
c.
d.
e.
has four times the magnitude of the force of Y
on X
has twice the magnitude of the force of Y on X
has the same magnitude as the force of Y on X
has one-fourth the magnitude of the force of Y
on X
has half the magnitude of the force of Y on X
a.
b.
c.
d.
2
a
b
c
d
ame: ________________________
14. Two charged particles are arranged as shown. In
which region is the electric field 0 N/C?
11. Consider this arrangement of particles. What is the
direction of the net force on the +3 µC charge?
a. III only
b. I & III only
c. I & II only
d. I only
e. II only
15. A -1 nC charge “floats” in an electric field. The
only forces on the charge are from gravity and the
electric field. The mass of the charge is 1x10 -9 kg.
What is the magnitude and direction of the electric
field? (Let g=10m/s 2)
a.
45° below the +x axis
b.
c.
d.
45° above the +x axis
along the +x axis
135° from the +x axis
12. What is the electric field at a distance of 3 m from
a 1 nC charge?
a. 10 N/C, upwards
b. 1 N/C, downwards
c. 10 N/C, downwards
d. 20 N/C, upwards
16. Consider the charges in this figure. Which of these
statements is true?
a. 1 N/C
b. 3 N/C
c. 9 N/C
d. 9x109 N/C
13. A proton is 3 m from a 1nC charge. What initial
acceleration does it experience?
a.
a.
b.
c.
d.
300,000,000 m/s2
100,000,000 m/s2
100,000 m/s2
200,000 m/s2
b.
c.
d.
3
both charges are positive and have the same
magnitude of charge
both charges are negative; the magnitude of A
is larger than that of B
charge A is positive; charge B is negative; both
have the same magnitude charge
both charges are positive; the magnitude of B is
larger than that of A
ame: ________________________
20. Two charges are arranged as shown. What is the
potential at point A?
17. A proton is accelerated by a constant electric field
of magnitude 300 N/C; the proton is moving in the
same direction as the electric field and is initially at
rest. What distance has the proton moved after
1x10-6 s?
a. 0.01 m
b. 1.4x10-6 m
c. 2.4x10-29 m
d. 100 m
18. Where on this line is the potential equal to zero?
a. 9 V
b. 0 V
c. 45 V
d. 27 V
21. A charged particle sits in an electric field as shown
here. If the particle follows the path shown by the
dashed line (ie, upwards), how much work is done
to move the particle?
a. a
b. b
c. c
d. d
e. e
19. Which of these is a conservative force?
I. Electric force
II. Frictional force
III. Gravitational force
IV. Electric potential
a. II
b. I, III, & IV
c. I & III
d. all of these
a.
b.
c.
d.
4
zero work
positive work
negative work
unable to tell without knowing the charge of
the particle
ame: ________________________
26. A 2 C charge crosses 2 plates separated by 0.01 m;
the high potential plate is 5V, and the low potential
side is -5V. How much kinetic energy does the
charge have moving across these 2 plates? (Hint:
What is the potential difference between the 2
plates?)
22. What is the potential and electric field at the point
P, which is in the center of this square?
a. E≠0, V≠0
b. E≠0, V=0
c. E=0, V=0
d. E=0, V≠0
23. Consider this charge. The arrows represent field
lines. The dashed lines represent equipotential
lines. What is the sign of the charge?
a. 20 J
b. 500 J
c. 200 J
d. 2000 J
e. 5 J
27. An electron is released at position x=A in the
potential described by the function in this figure.
What direction does it travel?
a. to the left
b. to the right
c. it remains stationary
d. it oscillates around A
28. What amount of work is required to assemble this
collection of charges?
a. positive
b. negative
c. there is no charge
24. For the previous question, where is the electric
potential the least?
a. both C & B
b. B
c. A
d. C
e. both A & D
25. The unit of electrical potential, the volt, is
dimensionally equivalent to:
a. J⋅C.
b. J/C.
c. F⋅C.
d. C/J.
a.
b.
c.
d.
5
12 J
6.8x10-9 J
2.4x10-8 J
1.3x10-8 J
ID: A
Exam 1--PHYS 102--S14
Answer Section
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