Name: ________________________ 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. 1023 C
b. 1019 C
c. 10-19 C
d. 10-23 C
e. 109 C
2. When you charge an object by induction, you...
a. touch the ball with a charged object.
b. bring a charged object near but do not touch
the ball.
c. induct the ball with charge.
d. move electrons from your finger to the ball.
3. An electrical insulator is a material:
a. cannot be a pure chemical element
b. containing no electrons
c. must be a crystal
d. through which electrons do not flow easily
e. that has more electrons than protons on its
surface
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.
b.
c.
A
B
C
d.
e.
D
E
1
Name: ________________________
5. 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is then withdrawn.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:
7. Two charged particles are arranged as shown. In
which region is the electric field 0 N/C?
a. I only
b. II only
c. III only
d. I & III only
e. I & II only
8. Consider the charges in this figure. Which of these
statements is true?
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
6. 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.
b.
c.
d.
a.
both charges are negative; the magnitude of A
is larger than that of B
b. charge A is positive; charge B is negative; both
have the same magnitude charge
c. both charges are positive and have the same
magnitude of charge
d. both charges are positive; the magnitude of B is
larger than that of A
9. Where on this line is the potential equal to zero?
a
b
c
d
a.
b.
c.
d.
e.
2
a
b
c
d
e
Name: ________________________
10. Which of these is a conservative force?
I. Electric force
II. Frictional force
III. Gravitational force
IV. Electric potential
a. I & III
b. II
c. I, III, & IV
d. all of these
11. 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?
13. For the previous question, where is the electric
potential the least?
a. A
b. B
c. C
d. both A & D
e. both C & B
14. The unit of electrical potential, the volt, is
dimensionally equivalent to:
a. J/C.
b. JC.
c. FC.
d. C/J.
15. An electron is released at position x=A in the
potential described by the function in this figure.
What direction does it travel?
a.
b.
c.
d.
zero work
positive work
negative work
unable to tell without knowing the charge of
the particle
12. Consider this charge. The arrows represent field
lines. The dashed lines represent equipotential
lines. What is the sign of the charge?
a.
b.
c.
a.
b.
c.
d.
positive
negative
there is no charge
3
to the left
to the right
it remains stationary
it oscillates around A
Name: ________________________
Problem
16. (20 pts) Consider this configuration of charges.
What is the magnitude and direction of the electric field at the point labeled “P?”
____________________________________________________________________
4
Name: ________________________
17. (10 pts)
A particle for which the mass is 10 g and the charge is 2C is in a potential field described by this
function:
V  3y 3 x  4xy
a) What is the electric field in vector notation at the point (x=1.0, y=1.0) meters?
b) What is the magnitude of the initial acceleration of this particle?
5
Name: ________________________
18. (15 pts) Consider this configuration of charges. How much work is required to assemble them in this way?
6
Name: ________________________
19. (15 pts) Consider this configuration of charges.
What is the potential at point “P?”
How much work is required to bring a -2C charge from an infinite distance away to the point “P?”
____________________________________________________________________
7
Name: ________________________
20. (10 pts) Consider this dipole. Label the electric field and equipotential lines. Draw, at least, 6 electric field and 6
equipotential lines.
8
ID: A
Exam 1--PHYS 102--S14
Answer Section
MULTIPLE CHOICE
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
C
B
D
C
D
C
A
C
B
A
A
A
D
A
A
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
PROBLEM
16. ANS:
.
PTS: 1
17. ANS:
.
PTS: 1
18. ANS:
.
PTS: 1
19. ANS:
.
PTS: 1
20. ANS:
.
PTS: 1
1