ame: ________________________
Exam 2--PHYS 102--S10
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. Which of these equations correctly describes this circuit?
a.
b.
____
80I 3 + 1I 3 + 30 + 45I 1 = 0
I1 + I2 = I3
c.
d.
−80I 3 − 1I 3 − 30 − 20I 2 − 40 = 0
45I 1 + 20I 2 − 40 = 0
2. What is the magnitude of the current I 1 in this circuit?
a.
b.
c.
2A
1.2 A
0.3 A
d.
e.
1
3.2 A
Not enough information
____
3. What is the equivalent resistance of this circuit?
____
a. 7 Ω
c. 0.5 Ω
b. 10 Ω
d. 2Ω
4. An RC circuit consists of a resistor of 1 M Ω and a capacitor of 4 µF. Assuming the capacitor is completely
charged by a battery of 2 V, how long will the capacitor require to fully discharge when it is disconnected
from the battery?
a.
b.
0.24 s
4s
c.
d.
2
40 s
8s
____
5. Which of these statements about a household circuit is true:
I. The household circuit is a parallel circuit.
II. All devices in a household circuit operate at the same current.
III. As you add more devices to a household circuit, the potential across each device
decreases.
IV. The circuit breaker turns off if I in>Iout for any particular device.
____
a. I & IV
c. I & II
b. I
d. II & III
6. In this circuit, how much brighter or dimmer is bulb A compared with bulb C? Assume the bulbs have the
same resistance.
A
C
B
10 V
a.
b.
c.
A is 4 times as bright as C
A is 1/2 as bright as C
A is 1/4 as bright as C
d.
e.
3
A is twice as bright as C
A has the same brightness as C
____
7. What is the potential across the resistor circled in this figure:
____
a. 3.3 V
c. 10 V
b. 2 V
d. 5 V
8. In this circuit, what happens to the equivalent resistance as you add resistors in parallel?
a.
b.
equivalent resistance decreases
equivalent resistance increases
c.
d.
4
equivalent resistance stays the same
It depends on the value of the added
resistance
____
9. On a circuit breaker, you have a 1200 W heater, a 120 W light bulb, and a 120 W radio. When you add a 480
W television, 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. 17 A
d. 12 A
b. 24 A
e. 15 A
c. 8 A
____ 10. A wire carries a current and sits in a magnetic field as shown. What is the direction of the force on the wire?
a. into the page
d. out of the page
b. up
e. down
c. left
____ 11. What is the initial direction of this positively charged particle when it enters the magnetic field as shown?
a.
b.
c.
right
into the page
up
d.
e.
5
out of the page
left
____ 12. This figure shows the path of a charged particle. What is the charge of the particle?
a. positive
c. neutral
b. negative
d. not enough information
____ 13. 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
1.6x10-19 C
Hydrogen
1.67x10-27 kg
1.6x10-19 C
Deuterium
3.35x10-27 kg
Tritium
5.01x10-27 kg
1.6x10-19 C
-27
3.2x10-19 C
Helium-3
5.01x10 kg
a.
b.
Tritium
Hydrogen
c.
d.
6
Deuterium
Helium-3
____ 14. Two parallel wires are 10 cm apart. One wire carries a current of 5 A to the left. The other carries a current
of 2 A to the right. What is the force acting on the wires if their length is 12 meters?
a.
b.
2.4×10-4 N, repelling
0.12 N, repelling
____ 15. Which pole of a magnet points towards the
c.
d.
2×10-3 N, attracting
2.4×10-4 N, attracting
magnetic north pole?
a. depends on where you are on the Earth
c. North
b. South
d. none of these
____ 16. The point A is equidistance between these two, long parallel wires. What is the direction of the magnetic
field at point A due to the two wires?
a.
b.
c.
Out of the page
Into the page
To the left
d.
e.
7
To the right
There is no magnetic field at A
____ 17. A wire carries a current of 2.0 A in a direction that makes an angle of 20.0º with the direction of a magnetic
field of strength 3.0 T. What is the magnetic force on a 10.0 m length of the wire?
a. 60 N
c. 6.8 N
b. 56 N
d. 21 N
____ 18. Which of these forms of radiation in the electromagnetic spectrum have the highest energy?
a. ultraviolet
c. radio
b. infrared
d. microwaves
____ 19. A ray of light travels from water to air. The angle of incidence, as depicted in this figure, is 45 degrees.
What is the refracted angle? (The index of refraction for water is 1.3.)
a. 41º
c. 67º
b. 45º
d. 23º
____ 20. A ray of light travels from water to air. What is the appropriate angle of incidence where total internal
reflection will occur? (The index of refraction for water is 1.3.)
a.
b.
c.
39º
1.3º
50º
d.
e.
8
45º
Total internal reflection will not occur
____ 21. Which of these relationships correctly describes the indices of refraction depicted in this figure?
a. n1<n2
c. n1>n2
b. n1=n2
d. Not enough information
____ 22. What physical property of glass allows for the creation of light-dispersing prisms?
a.
the index of refraction for glass is higher c. light travels slower in glass than air
than that of air
b. the dependence of the index of refraction d. the triangular shape of prisms
on wavelength
____ 23. Which of these phenomena suggest that light acts as a particle?
I. Interference
II. Reflection
III. Refraction
IV. Photoelectric Effect
a. IV
c. II & IV
b. II & III
d. I & IV
8
____ 24. The speed of light in a vacuum is 3x10 m/s. Glass has an index of refraction of n=1.5. What is the speed of
light in glass?
a.
b.
3x108 m/s
6x108 m/s
c.
d.
9
2x108 m/s
4.5x108 m/s
____ 25. This figure shows a person looking at a star in a box filled with water. The actual position of the star is as
shown. Where does the person see the image of the star?
a.
the image is at the same position as the
object
b. to the right of the actual star
____ 26. This is version B. Bubble B for this question.
a. A
b. B
c.
to the left of the actual star
d.
the person does not see an image
c.
d.
C
D
10
ID: A
Exam 2--PHYS 102--S10
Answer Section
MULTIPLE CHOICE
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