Name: ________________________
Block: ________________________
Honors Physics
TEST: Waves
Mr. Miller
May 11, 2005
NOTES:
 Please place answers to the multiple choice on the cover sheet and the answers to the free
response section in the appropriate boxes.
 Be sure your calculator is in the correct mode, either degrees or radians.
 NO extra time will be given for this test.
 The test is written out of 125 points; your score will be doubled to obtain a score out of 250
points.
 There are two extra credit problems on the back of this sheet.
Part I: Multiple Choice (30 Points Total). Place your answers on this sheet.
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9. __________
2. __________
10. __________
3. __________
11. __________
4. __________
12. __________
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Part I: Multiple Choice
Part II: Short Answer
Part I TOTAL: __________ / 30
Part II TOTAL: __________ / 40
Part III: Free Response
Question 1: __________ / 5
Question 3: __________ / 25
Question 2: __________ / 15
Question 4: __________ / 10
Extra Credit: __________ / 5
Part II TOTAL: __________ / 55
ASSESSMENT SUBTOTAL: _____________________ / 125
ASSESSMENT TOTAL: _____________________ / 250
PART I: MULTIPLE CHOICE (2 POINTS EACH)
Please place answers on answer sheet.
1) As a gust of wind blows across a field of
grain, a wave can be seen to move
across the field as the tops of the plants
sway back and forth. This wave is a
a) Transverse wave
b) Longitudinal wave
c) Polarized wave
d) Interference of waves
6) How many anti-nodes does this
standing wave have?
2) The wavelength of a traveling wave is a
function of:
a) Frequency
b) Velocity
c) Amplitude
d) Both choices A and B
a)
b)
c)
d)
3) The diagram illustrating two waves in
phase is:
One
Two
Three
Four
7) The pictures below represent vibrating
guitar strings. Which picture shows a
guitar string of one and only one
wavelength?
a)
b)
c)
d)
4) Destructive interference occurs
because:
a) Multiple waves combine to make a
wave of smaller amplitude
b) Waves bend around or through
holes in an obstacle
c) Waves are absorbed and disappear
d) Two waves add up to make a wave
of larger amplitude
8) Consider two identical wave pulses on a
string. Suppose the first pulse reaches
the fixed end of the string and is
reflected back and then meets the
second pulse. When the two pulses
overlap exactly, the superposition
principle predicts that the amplitude of
the resultant pulses, at that moment, will
be what factor times the amplitude of
one of the original pulses?
a) 0
b) 1
c) 2
d) 4
5) We often hear beats (rapid alternating
between loudness and silence) when:
a) Musical notes have the same
frequency as the rhythm
b) Two notes played at the same time
have nearly the same frequency
c) Sound is created as a percussionist
hits a bass drum
d) There is interference due to multiple
echoes
9) Tripling the tension in a guitar string will
result in changing the wave velocity in
the string by what factor?
a) 0.58
b) 1.00
c) 1.73
d) 3.00
Page 1
10) If the frequency of a traveling wave train
is increased by a factor of three in a
given medium, which of the following is
the result?
a) Amplitude is one third as big
b) Amplitude is tripled
c) Wavelength is one third as big
d) Wavelength is tripled
Questions 14-15:
Two pulses are shown traveling in opposite
directions on a rope.
14) After one second, the crest C and
trough D are at point P. Which shape
best represents the shape of the rope at
this time?
11) Sound waves are always
a) Transverse waves
b) Longitudinal waves
c) Electromagnetic waves
d) Seismic waves
12) A period wave travels along a stretched
string in the direction shown by the
arrow. The sketch shows a “snapshot”
of the pulse at a certain instant. Points
A, B, and C are on the string. Which
entry in the table below correctly
describes how the particles of the string
between A and B and B and C are
moving?
15) Which best represents the shape of the
rope one second later (i.e., one second
after crest C and trough D were at point
P)?
(d) none of these
between A and B
a) Down
b) Up
c) Left
d) Up
e) Down
between B and C
down
up
right
down
up
13) By what factor does the velocity on a
string chance when the frequency is
doubled? (Assume the tension remains
the same)
a) ¼
b) ½
c) 0
d) 2
e) 4
Page 2
PART II: Short Answer (2 points each)
1. In a stretched string, what variables does wave velocity depend upon?
________________
2. What phase is a wave that is reflected from a more rigid medium?
________________
3. What phase is a wave that is reflected from a less rigid medium?
________________
4. What phase is a wave that is transmitted from a more rigid to less rigid medium? ________________
5. What phase is a wave that is transmitted from a less rigid to more rigid medium? ________________
6. What variable(s) stays the same when a wave is transmitted across a boundary? ________________
7. When waves enter a more rigid medium, what happens to their velocity?
________________
8. When waves enter a more rigid medium, what happens to their wavelength?
________________
9. When waves enter a less rigid medium, what happens to their velocity?
________________
10. When waves enter a less rigid medium, what happens to their wavelength?
________________
11. What type of interference occurs when two waves meet in phase?
________________
12. What type of interference occurs when two waves meet out of phase?
________________
13. What type of wave is shown below?
________________
On the wave above, label the:
14. compressions,
15. rarefactions, and
16. wavelength
17. What type of wave is shown below?
________________
One the wave above, label the:
18. amplitude,
19. wavelength,
20. crest and trough.
Page 3
PART III: FREE RESPONSE
These questions are open response questions. Please show all work, including the formulas used. Be
sure to include units for all answers. Place answers in the given boxes.
PROBLEM 1 (5 Points):
A fisherman notices that wave crests pass the bow of his anchored boat every 3.0 s. He measures the
distance between two crests to be 8.5 m. How fast are the waves traveling?
v=
PROBLEM 2 (15 Points):
A. Discuss the similarities and differences between the two types of waves examined in the Slinky and
Snaky lab.
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B. Light and sound waves are extremely different. In a well-constructed response, examine these
differences. In your answer, assume that the reader knows VERY little about physics; therefore,
clearly explain the terminology you use.
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Page 4
PROBLEM 3 (25 Points):
One end of a horizontal string of linear density 4.3 x 10 -4 kg/m is attached to a small-amplitude
mechanical 120-Hz vibrator. The string passes over a pulley, a distance L = 1.50 m away, and weights
are hung from this end as shown in the figure.
What mass m must be hung from this end of the string to produce a standing wave with
A. one loop
B. five loops?
C. Now, the length of the string may be adjusted by moving the pulley. If the hanging mass is fixed
at 0.080 kg, how many different standing wave patters may be achieved by varying L between 10
cm and 1.5 m? (be sure to show work for partial credit)
D. Why can the amplitude of the standing wave be much greater than the vibrator amplitude?
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A. m =
B. m =
C.
D. answer above
PROBLEM 4 (10 Points):
Page 5
The waves shown in the diagram below are square pulse waves. If wave I meets wave II, shown their
superposition on the line below.
I:
2
1.5
1
0.5
0
0
2
4
6
8
10
12
14
16
18
20
0
2
4
6
8
10
12
14
16
18
20
6
8
10
12
14
16
18
20
-0.5
-1
-1.5
-2
II:
2
1.5
1
0.5
0
-0.5
-1
-1.5
-2
Superposition:
2
1.5
1
0.5
0
0
2
4
-0.5
-1
-1.5
-2
We’re almost done with the year? I can’t believe that our ride together is coming to an end. What’s up
with you? How are you doing? What’s new?
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EXTRA CREDIT 1 (2 POINTS)
The ripples in a certain groove 12.8 cm from the center of a 33-rpm phonograph have a wavelength of
1.70 mm. What will be the frequency of the sound emitted?
f=
EXTRA CREDIT 2 (3 POINTS)
Show that the frequency of standing waves on a string of length L and linear density m, which is stretched
to a tension FT, is given by
f 
n
2L
where n is an integer.

Page 7
FT
