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Electrostatics and Electricity
Name: Yi Hang Chen Attempt: 1 / 2 Out of: 20
Started: May 17, 2004 Finished: May 17, 2004 Time spent: 43 min. 7
10:25pm 11:08pm sec.
Student finished 46 min. 53 sec. ahead of the 90 min. time limit.
Question 1 (1 point)
Each of three objects has a net charge. Object A and B attract one another. Objects B and
C also attract one another, but objects A and C repel one another. Which of the following
table entries is a possible combination of the signs of the net charges on these three
objects?
Student response: Percent Student Answer Choices
Value Response
a. ABC
++-
b. ABC
-++
c. ABC
+--
100.0% d. ABC
-+-
e. ABC
--+
Score: 1/1
Question 2 (1 point)
A conducting sphere has a net charge of -4.8 x 10*-17C. What is the approximate number
of excess electrons on the sphere?
Student response: Percent Student Answer Choices
Value Response
a. 100
b. 200
100.0% c. 300
d. 400
e. 500
Score: 1/1
Question 3 (1 point)
Three charged particles A, B, and C are located near one another. Both the magnitude and
direction of the force that particle A exerts on particle B is inependent of
Student response: Percent Student Answer Choices
Value Response
V a. the sign of charge B
b. the sign of charge A
c. the distance between C and B
d. the distance between A nad B
0.0% e. the magnitude of the charge on
B
Score: 0/1
Question 4 (1 point)
A charge Q exerts a 12 N force on another charge q. If the distance between the charges
is doubled, what is the magnitude of the force exerted on Q by q?
Student response: Percent Student Answer Choices
Value Response
100.0% a. 3N
b. 6N
c. 24N
d. 36N
e. 48N
Score: 1/1
Question 5 (1 point)
Two positive point charges Q and 2Q are separated by a distance R. If the charge Q
experiences a force of magnitude F when the separation is R, what is the magnitude of
the force on the charge 2Q when the separation is 2R?
Student response: Percent Student Answer Choices
Value Response
100.0% a. F/4
b. F/2
c. F
d. 2F
e. 4F
Score: 1/1
Question 6 (1 point)
Which of the following statements is true concerning the magnitude of the electric field at
a point in space?
Student response: Percent Student Answer Choices
Value Response
a. It is a measure of the total
charge on the object.
b. It is a measure of the electric
force on any charged object.
c. It is a measure of the ratio of the
charge on an object to its mass.
d. It is a measure of the electric
force per unit mass on a test
charge.
100.0% e. It is a measure of the electric
force per unit charge on a test
charge.
Score: 1/1
Question 7 (1 point)
Which one of the following statements is true concerning the spacing of the electric field
lines in the vicinity of two point charges of equal magnitude and opposite sign?
Student response: Percent Student Answer Choices
Value Response
a. It indicates the direction of the
electric field.
0.0% b. It does not depend on the
magnitude of the charges.
c. It is large when the magnitude
of the charges is large.
V d. It indicates the relative
magnitude of the electric field.
e. It is small when the magnitude
of the charges is small.
Score: 0/1
Question 8 (1 point)
What is the magnitude and direction of the electric force on a -1.2uC charge at a point
where the electric field is 2500N/C and is directed along the +y axis.
Student response: Percent Student Answer Choices
Value Response
a. 0.15N, -y direction
b. 0.15N, +y direction
100.0% c. 0.0030N, -y direction
d. 0.0030N, +y direction
e. 4.3N, +x direction
Score: 1/1
Question 9 (1 point)
Two positive point charges are separated by a distance R. If the distance between the
charges is reduced to R/2, what happens to the total electric potential energy of the
system?
Student response: Percent Student Answer Choices
Value Response
100.0% a. It is doubled.
b. It remains the same.
c. It increases by a factor of 4.
d. It is reduced to one-half of its
original value.
e. It is reduced to one-fourth of its
original value.
Score: 1/1
Question 10 (1 point)
If the work required to move a +0.35C charge from point A to point B is +125J, what is
the potential difference between the two points?
Student response: Percent Student Answer Choices
Value Response
a. zero volts
b. 44V
c. 88V
d. 180V
100.0% e. 360V
Score: 1/1
Question 11 (1 point)
Which one of the following statements best describes the equipotential surfaces
surrounding a point charge?
Student response: Percent Student Answer Choices
Value Response
a. The equipotential surfaces are
planes extending radially
outward from the charge.
b. The equipotential surfaces are
curved planes surrounding the
charge, but only one passes
through the charge.
c. The equipotential surfaces are
concentric cubes with charge at
the centre.
100.0% d. The equipotential surfaces are
concentric spheres with the
charge at the centre.
e. The equipotential surfaces are
concentric cylinders with the
charge on the axis at the centre
Score: 1/1
Question 12 (1 point)
Which of the following situations results in a conventional electric current that flows
westward?
Student response: Percent Student Answer Choices
Value Response
a. a beam of protons moves
eastward
b. an electric dipole moves
westward
c. a beam of electrons moves
westward
100.0% d. a beam of electron moves
eastward
e. a beam of neutral atoms moves
westward
Score: 1/1
Question 13 (1 point)
The potential difference across the ends of a wire is doubled in magnitude. If Ohm's law
is obeyed, which of the following statements concerning the resitance of the wire is true?
Student response: Percent Student Answer Choices
Value Response
a. The resistance is one half of its
original value.
b. The resistance is twice its
original value.
100.0% c. The resistance is not changed.
d. The resistance increases by a
factor of four.
e. The resistance decreases by a
factor of four.
Score: 1/1
Question 14 (1 point)
When a light bulb is connected to a 4.5 V battery, a current of 0.16 A passes through the
bulb filamnet. What is the resistance of the filament
Student response: Percent Student Answer Choices
Value Response
a. 440 ohms
100.0% b. 28 ohms
c. 9.3 ohms
d. 1.4 ohms
e. 0.72 ohms
Score: 1/1
Question 15 (1 point)
A 4-A current is maintained in a simple circuit with a total resistance of 2 ohms. How
much energy is dissipated in 3 seconds?
Student response: Percent Student Answer Choices
Value Response
a. 3J
b. 6J
c. 12J
d. 24J
100.0% e. 96J
Score: 1/1
Question 16 (1 point)
Which one of the following statements concerning resistors in series is true?
Student response: Percent Student Answer Choices
Value Response
a. The voltage across each resistor
is the same.
100.0% b. The current through each
resistor is the same.
c. The power dissipated by each
resistor is the same.
d. The rate at which charge flows
through each resistor depends
on its resistance.
e. The total current through the
resistors is the sum of the
current through each resistor.
Score: 1/1
Question 17 (1 point)
Three resistors, 50-ohms, 100-ohms, 200-ohms, are connected in series in a circuit. What
is the equivalent resistance of this combination of resistors?
Student response: Percent Student Answer Choices
Value Response
100.0% a. 350 ohms
b. 250 ohms
c. 200 ohms
d. 120 ohms
e. 29 ohms
Score: 1/1
Question 18 (1 point)
Complete the following statement: A simple series circuit contains a resistance R and an
ideal battery. If a second resistor is connected in parallel with R,
Student response: Percent Student Answer Choices
Value Response
a. the voltage across R will
decrease.
b. the current through R will
decrease.
100.0% c. the total current through the
battery will increase.
d. the rate of energy dissipation in
R will increase.
e. the equivalent resistance of teh
circuit will increase.
Score: 1/1
Question 19 (1 point)
Two resistors, 6.0 ohms, 9.0 ohms, are connected in parallel in a circuit. What is the
equivalent resistance of this combination of resistors?
Student response: Percent Student Answer Choices
Value Response
a. 30 ohms
b. 10 ohms
c. 2.9 ohms
100.0% d. 3.6 ohms
e. 0.34 ohms
Score: 1/1
Question 20 (1 point)
A non-ideal battery has a 6.0 V emf and an internal resistance of 0.6 ohms. Determine the
terminal voltage when the current drawn from the battery is 1.0 A.
Student response: Percent Student Answer Choices
Value Response
a. 5.0V
b. 6.0V
100.0% c. 5.4V
d. 6.6V
e. 5.8V
Score: 1/1
Total score: 18 / 20 = 90.0%