ame: ________________________
Exam 2--PHYS 202--Chapers 4 & 5--S13
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. Which of the following equations for this circuit is
1Ω
I1
4V
3Ω
5V
I2
2Ω
a.
b.
____
correct?
I3
12 V
4-2I1-12-3I3=0
-4-I2+5+2I1=0
c.
d.
I1+I3=I2
-I1+5-12=0
2. Which of these statements about a household circuit is true:
I. The household circuit is a series circuit.
II. All devices in a household circuit operate at the same current.
III. As you add more devices to a household circuit, the total current increases.
IV. A ground fault circuit interrupt turns off if I in>Iout for any particular device.
a.
b.
III & IV
I & IV
c.
d.
1
III
II & III
____
3. The wires in this junction have currents as labeled. What is the unknown current (labeled I=?)?
a.
b.
____
c.
d.
8A
10 A
4. If the switch S is closed, what happens to the potential across
a.
b.
____
12 A
2A
increases
decreases
c.
d.
R1?
stays the same
not enough information
5. Two resistors are connected in series with a 18 V battery. One of the resistors has a potential of 6 V.
What is the potential across the other resistor?
a.
b.
____
12 V
24 V
c.
d.
4V
18 V
6. What purpose does the third prong on a three-prong outlet serve?
a. Act as a ground thus providing a
c. Allow for more stability in the outlet
safety feature
b.
No purpose
d.
2
An alternative to the European system
of electrical outlets
____
7. In a single circuit within your house, what happens to the total resistance as you add electrical appliances?
a.
b.
____
c.
d.
the resistance stays the same
none of these
8. How are natural magnets created?
a.
b.
____
the resistance decreases
the resistance increases
ferromagnetic materials undergo very
c.
high pressure and temperature
molten metal solidifies in the presence of d.
a magnetic field
fossilized dinosaurs are magnetic
iron mixes with magnetic particles to
create a stronger magnet
9. Which of these statements is true?
a.
b.
all permanent magnets are ferromagnetic c.
opposite poles of a magnet attract
d.
magnetic monopoles do not exist
all of these are true
____ 10. The Earth’s magnetic field plays a role in which of these atmospheric phenomena:
a.
b.
mirages
atmospheric refraction
c.
d.
aurora borealis
high-energy particle showers
____ 11. A negatively charged particle enters a magnetic field as shown. What is the force acting on the particle?
a.
c.
b.
d.
3
____ 12. This wire is in a magnetic field as shown. The wire feels a force to the right. What is the direction of the
current
a.
b.
up
down
c.
d.
zero
not enough information
____ 13. A coil of copper wire, which is allowed to rotate about the axis shown with the dashed line, has a current
going through it as shown. What is the initial direction of rotation for the coil?
a.
b.
Counterclockwise
Clockwise
c.
It remains stationary
____ 14. This figure shows the path of a charged particle. What is the charge of the particle?
a.
b.
positive
negative
c.
d.
4
neutral
not enough information
Problem
15. (25 pts) Label the currents in this circuit. Calculate each current and give its magnitude
direction . Solving the system of equations by Gaussian elimination is worth 5 extra
points.
.
5
and
16. (15 pts) What is the current and resistance for each of the resistors shown in this figure? Also, what is the
power dissipated by each resistor?
.
6
17. (20 pts) This circuit shows a 2.8 m length of wire that is oriented at 45 degrees from the +x axis. The wire is
part of a circuit as shown. The magnetic field has a magnitude of 3 T in the -z direction. Give the force on
the wire in vector notation.
7
18. (10 pts) A proton moves freely in a circular path perpendicular to a constant magnetic field. The
proton takes 1.2 µs to complete 1 revolution. Determine the magnitude of the magnetic field.
.
8
ID: A
Exam 2--PHYS 202--Chapers 4 & 5--S13
Answer Section
MULTIPLE CHOICE
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
B
A
A
A
A
A
A
B
D
C
C
B
B
B
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
PROBLEM
15. ANS:
.
PTS: 1
16. ANS:
.
PTS: 1
17. ANS:
.
PTS: 1
18. ANS:
.
PTS: 1
1