ame: ________________________
Exam 2--PHYS 102--S12
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. Which of these equations is correct?
a.
b.
14 + 4I 1 + 10 + 6I 2 = 0
10 + 6I 2 + 6 = 0
c.
d.
I1 + I3 = I2
14 − 4I 1 + 6 = 0
____
2. For the above circuit, what is the current through the 4 Ω resistor?
____
a. 5 A
b. 3 A
3. What does a circuit breaker do?
a.
b.
creates a parallel circuit in your house
turns off if the input current exceeds the
output current
c.
d.
6A
2A
c.
d.
provides an alternate ground
turns off if the current exceeds a certain
amount
1
____
4. What is the current through the 1Ω resistor?
____
a. 2.4 A
c.
b. 9 A
d.
5. What value is constant for all household devices?
a.
b.
current
power
c.
d.
2
3A
6A
charge
voltage
____
6. What is the equivalent resistance of this circuit?
____
a. 19 Ω
c. 5.0 Ω
b. 3.3 Ω
d. 2.0 Ω
7. For the previous circuit, what is the current through R 1?
____
a. 2.0 A
c. 50 A
b. 10 A
d. 0.5 A
8. For the previous circuit, what is the voltage across R 5?
____
a. 10. V
c. 6.0 V
b. 4.0 V
d. 8.0 V
9. On a circuit breaker, you have a 1200 W heater and a 720 W fan. When you add a 240 W blender, the circuit
breaker turns off. Assume all the devices operate at 120 V. Which of these is the maximum allowed current
for the breaker?
a.
b.
8A
13 A
c.
d.
3
19 A
17 A
____ 10. The wires in this junction have currents as labeled. What is the unknown current (labeled I=?)?
a.
b.
2A
10 A
c.
d.
14 A
6A
____ 11. If the switch S is closed, what happens to the potential across
a.
b.
decreases
stays the same
c.
d.
4
R1?
increases
not enough information
____ 12. What is the potential across the
4Ω
Ω resistor?
a. 0.5 V
c. 8 V
b. 2 V
d. 4 V
____ 13. In a circuit with resistors in parallel, what happens to the equivalent resistance as you add more resistors in
parallel?
a.
b.
Req increases
Req decreases
c.
d.
Req stays the same
It depends on the value of the added
resistance
c.
d.
2A
6A
____ 14. What is the current in the 3Ω resistor (R 1)?
a.
b.
54 A
9A
5
____ 15. How are natural magnets created?
a.
ferromagnetic materials undergo very
high pressure and temperature
b. iron mixes with magnetic particles to
create a stronger magnet
____ 16. Which of these statements is true?
c.
fossilized dinosaurs are magnetic
d.
molten metal solidifies in the presence of
a magnetic field
a. all permanent magnets are ferromagnetic c. magnetic monopoles do not exist
b. opposite poles of a magnet attract
d. all of these are true
____ 17. The Earth’s magnetic field plays a role in which of these atmospheric phenomena:
a. aurora borealis
c. high-energy particle showers
b. atmospheric refraction
d. mirages
____ 18. A negatively charged particle enters a magnetic field as shown. What is the force acting on the particle?
a.
c.
b.
d.
____ 19. A wire carries a current of 5.0 A in direction that makes an angle of 15º from a magnetic field that has a
magnitude of 3.0 T. What is the magnetic force on a 2.5 m length of wire?
a.
b.
c.
13 N
38 N
37 N
d.
e.
6
9.7 N
15 N
____ 20. An electron moves freely in a circular path perpendicular to a magnetic field. The electron requires 1.0 µs to
complete 1 revolution. What is the magnitude of the magnetic field?
c. 3.4 T
a. 1×10-6 T
d. 5.7×10-12 T
b. 3.6×10-5 T
____ 21. I pass a wire through a magnetic field as shown. The wire has a length of 2.0 m. The magnetic field is 8.0 T.
The force you apply is 32 N. What is the current in the wire?
a. 0.000020 A
c. 2.0 A
b. 0.50 A
d. 510 A
____ 22. For the previous question, what is the direction of the current?
a. to the right
c. to the left
b. not enough information
7
____ 23. A current travels through a wire as shown. What is the direction of the force on the wire?
a. up
d. into the page
b. to the right
e. to the left
c. down
____ 24. 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. Clockwise
c. It remains stationary
b. Counterclockwise
____ 25. This figure shows the path of a charged particle. What is the charge of the particle?
a.
b.
negative
positive
c.
d.
8
neutral
not enough information
____ 26. A charged particle enters a mass spectrometer. The magnetic field inside the device is 0.4 T, the velocity of
the particle is 2.0x10 6 m/s, and the radius of the particle’s path is 0.052 m. From the information given here,
what is this particle?
Particle
Mass
Charge
-27
1.6x10-19 C
Hydrogen
1.67x10 kg
-27
1.6x10-19 C
Deuterium
3.35x10 kg
1.6x10-19 C
Tritium
5.01x10-27 kg
-27
Helium-3
5.01x10 kg
3.2x10-19 C
a. Deuterium
c. Helium-3
b. Hydrogen
d. Tritium
____ 27. You are using version A of this exam. Bubble A for this question.
a. A
c. C
b. B
d. D
9
ID: A
Exam 2--PHYS 102--S12
Answer Section
MULTIPLE CHOICE
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