Physics 101.001                                 Test 1 – Answers                      February 7, 2001

 

Read each question and its set of answers very carefully.  There is only one best answer for each question.  Don’t be afraid to ask questions of me during the exam.  Just raise your hand if you have one.

 


   1.  The part of a standing wave that is not moving at all is a (an)

(a) rarefaction

(b) node

(c) compression                           

(d) crest

(e) antinode

 

   2.  The Doppler effect is the apparent change in the speed of a wave due to the motion of the source or observer.

(a) True                                         

(b) False

 

   3.  Is the Doppler effect characteristic of longitudinal waves, transverse waves, or both?

(a) longitudinal                            

(b) transverse

(c) both

 

   4.  Frequencies of sound that are too high for the human ear to hear are called

(a) faster than the speed of sound

(b) supersonic

(c) infrasonic

(d) ultrasonic

(e) subsonic

 

   5.  A sound wave in air can best be described as

(a) a transverse wave                 

(b) a longitudinal wave

(c) a standing wave                    

(d) a shock wave

 

   6.  Which part of a sound wave has the higher air pressure?

(a) condensation                         

(b) rarefaction

 

   7.  Compared to solids and liquids, how does air rank as a conductor of sound?

(a) very good               

(b) favorably

(c) poorly

 

   8.  What is the approximate distance of a thunderstorm when you note a 3-s delay between the flash of lightning and the sound of thunder?

(a) 330 m                                       

(b) 1100 ft

(c) 3300 ft                                      

(d) 3 miles

 

   9.  An oceanic depth‑sounding vessel surveys the ocean bottom with ultrasonic sound that travels 1530 m/s in seawater.  Find the depth in meters of the water if the time delay of the echo from the ocean floor is 6s.

(a) 1530                                         

(b) 4590

(c) 9180                                         

(d) 1530/6

 

10.  Sound travels faster on hot days than on cold days.

(a) True                                         

(b) False


11.  On a cold morning, when the air near the ground is cooler than the air above it, sound waves

(a) travel faster than on warm days

(b) from a distant source are muffled

(c) have a lower frequency than on warm days

(d) tend to be refracted upward

(e) tend to be refracted downward

 

12.  The energy of a sound wave generated by a person talking is

(a) about the same as the energy of an ordinary light bulb

(b) greater than the energy of an ordinary light bulb

(c) much less than the energy of an ordinary light bulb

 

13.  A 212 Hz tuning fork can induce vibrations into a 106 Hz tuning fork.

(a) True                                         

(b) False

 

14.  We can distinguish between the sound of a wrench dropped on a floor and a baseball bat dropped on a floor because of the                      of each object.

(a) reverberation                          

(b) resonance

(c) interference                            

(d) natural frequency

(e) beating

 

15.  Which of the devices demonstrated in lecture was not an example of resonance?

(a) the singing glass (brandy snifter)

(b) the long metal rod

(c) the vortex box

(d) the matched tuning forks mounted on boxes

 

16.  Why was the sound of a tuning fork amplified when the fork was held against a table?

(a) the table set more air in motion due to its large surface

(b) the table causes the fork to vibrate harder

(c) the table amplified the sound by reverberation

(d) the table allowed the sound to travel faster than in air

 

17.  The singing glass demonstration performed in class was an example of

(a) natural frequency                  

(b) resonance

(c) forced vibration                     

(d) all of the above

(e) none of the above

 

18.  The periodic variation in the loudness of sound known as beats is due to

(a) interference                            

(b) resonance

(c) forced vibrations                   

(d) reflection

(e) refraction

 

19.  The three characteristics of a musical tone are loudness, quality, and pitch.

(a) True                                         

(b) False

 

20.  At an outdoor concert, will the pitch of musical tones be affected on a windy day?

(a) Yes                                           

(b) No

 

21.  Doubling the intensity of a sound also doubles the loudness.

(a) True                                         

(b) False

 

22.  If the note middle C has a pitch of 262 vibrations per second, its second overtone on a vibrating string has a frequency of

(a) 131 vibrations per second

(b) 262 vibrations per second

(c) 524 vibrations per second

(d) 786 vibrations per second

(e) none of the above

 

23.  The fifth harmonic in a closed organ pipe corresponds to which overtone?

(a) third                                         

(b) fourth

(c) second                                    

(d) first

 

24.  Like a pendulum you swing an empty suitcase to and fro at its natural frequency.  If the case were filled with books, the natural frequency would be

(a) decreased                                               

(b) increased

(c) the same as before

 

25.  The period of the second hand on a watch is (think carefully)

(a) 1 minute                                  

(b) 1 second

(c) 1 hour                                      

(d) 12 hours

(e) 24 hours

 

26.  What dictates the frequency of a sound wave?

(a) wavelength                             

(b) medium

(c) source of the sound              

(d) speed

(e) amplitude

 

27.  Which is the frequency in cycles per second of a 1100 Hz wave?

(a) 1100                                         

(b) 1

(c) 1/1100                                      

(d) none of the above

 

28.  If a water wave oscillates up and down three times each second and the distance between wave crests is 2 m, what is its speed in meters per second?

(a)   2             

(b) 2/3                            

(c) 6                               

(d) 3

 

29.  As the frequency of a wave of constant speed is increased, does the wavelength increase or decrease?

(a) increase                                   

(b) decrease

(c) remains unchanged

 

30.  The relationship among velocity , wavelength , and frequency  is

(a)                                  

(b) 

(c) 

 

31.  What determines the speed of a wave?

(a) the frequency

(b) the wavelength

(c) the amplitude

(d) the period

(e) the medium of transmission

 

32.  In a transverse wave, the individual particles of the medium

(a) move in circles

(b) move in ellipses

(c) move parallel to the direction of travel of the wave

(d) move perpendicular to the direction of travel of the wave

 

33.  Standing waves cannot be established using longitudinal waves.

(a) True                                         

(b) False