ASLP 3030 Exam 1 ACTUAL Exam
Questions and CORRECT Answers
What is acoustic? - CORRECT ANSWER - Acoustics refers to the scientific study of
sound waves in terms of how it is generated and transmitted.
Why do we study wave motions and oscillation in acoustics? - CORRECT ANSWER - We
study the properties of wave motion and oscillation in order to have a precise understanding of
sound waves and their characteristics.
What are the essential properties of sound source and sound medium? - CORRECT
ANSWER - Mass and elasticity
-Elasticity is the ability of an object to return to its original form after being
stretched or compressed.
The sound source and sound medium are independent of each other. Sound source is the sound
generator (example, a tuning fork). Sound medium is the sound carrier (example,
the air or helium). The frequency and period of a sound are determined by the properties of the
source. The speed of sound transmission is determined by the properties of the medium.
How do sound waves propagate? - CORRECT ANSWER - When set into motion, air
molecules oscillate back and forth about their equilibrium positions, causing adjacent air
molecules to move closer together and air pressure to increase (condensation) and then move
further apart causing air pressure to decrease (rarefaction). It is the disturbance which travels, not
the individual air particles in the medium. Sound waves propagate in a spherical, longitudinal
fashion
What do amplitude, frequency and period of sound mean? - CORRECT ANSWER -
Amplitude refers to the displacement of particles during vibration. It is related to sound
pressure and intensity.
Frequency refers to how many cycles per second the vibration takes place.
Period refers to the amount of time to complete one cycle of vibration.
Period (in seconds) is the inverse of frequency (in Hertz).
, Period (Ts) = 1/Frequency (Hz)
Frequency (Hz) = 1/Ts (Period in seconds)
If the period is in seconds, frequency is in Hertz
What happens to the amplitude of a sound as it propagates? - CORRECT ANSWER - As a
sound propagates, the sound pressure changes in inverse proportion to the square of
the distance from the source (Inverse Square Law), meaning that the further the sound wave
travels, the lesser the sound pressure level
What are the characteristics of Simple Harmonic Motion? - CORRECT ANSWER -•
SHM is characterized by patterns of acceleration an deceleration over time
• Velocity or SPEED is not constant throughout the movement, but the same movement is
repeated over and over again
• The first stage of movement or swing is identical to the second swing, etc
• And this type of movement can be GRAPHED
• And that graph results in something called a SINE WAVE because it can be
described in mathematical terms
What is phase? - CORRECT ANSWER - Phase describes the specific position of a
waveform in its cycle at a specific moment in
time and is expressed in angles (0, 90, 180, 270, 360 degrees)
• Starting phase - the point at which sound begins to vibrate
What type of interference happens when 2 sound waves with the same frequency are exactly 180
degrees out of phase? - CORRECT ANSWER - When 2 sound waves of the same
frequency that are 180 degrees out of phase interact, there is destructive interference and the two
waves will cancel each other out, resulting in
silence
Questions and CORRECT Answers
What is acoustic? - CORRECT ANSWER - Acoustics refers to the scientific study of
sound waves in terms of how it is generated and transmitted.
Why do we study wave motions and oscillation in acoustics? - CORRECT ANSWER - We
study the properties of wave motion and oscillation in order to have a precise understanding of
sound waves and their characteristics.
What are the essential properties of sound source and sound medium? - CORRECT
ANSWER - Mass and elasticity
-Elasticity is the ability of an object to return to its original form after being
stretched or compressed.
The sound source and sound medium are independent of each other. Sound source is the sound
generator (example, a tuning fork). Sound medium is the sound carrier (example,
the air or helium). The frequency and period of a sound are determined by the properties of the
source. The speed of sound transmission is determined by the properties of the medium.
How do sound waves propagate? - CORRECT ANSWER - When set into motion, air
molecules oscillate back and forth about their equilibrium positions, causing adjacent air
molecules to move closer together and air pressure to increase (condensation) and then move
further apart causing air pressure to decrease (rarefaction). It is the disturbance which travels, not
the individual air particles in the medium. Sound waves propagate in a spherical, longitudinal
fashion
What do amplitude, frequency and period of sound mean? - CORRECT ANSWER -
Amplitude refers to the displacement of particles during vibration. It is related to sound
pressure and intensity.
Frequency refers to how many cycles per second the vibration takes place.
Period refers to the amount of time to complete one cycle of vibration.
Period (in seconds) is the inverse of frequency (in Hertz).
, Period (Ts) = 1/Frequency (Hz)
Frequency (Hz) = 1/Ts (Period in seconds)
If the period is in seconds, frequency is in Hertz
What happens to the amplitude of a sound as it propagates? - CORRECT ANSWER - As a
sound propagates, the sound pressure changes in inverse proportion to the square of
the distance from the source (Inverse Square Law), meaning that the further the sound wave
travels, the lesser the sound pressure level
What are the characteristics of Simple Harmonic Motion? - CORRECT ANSWER -•
SHM is characterized by patterns of acceleration an deceleration over time
• Velocity or SPEED is not constant throughout the movement, but the same movement is
repeated over and over again
• The first stage of movement or swing is identical to the second swing, etc
• And this type of movement can be GRAPHED
• And that graph results in something called a SINE WAVE because it can be
described in mathematical terms
What is phase? - CORRECT ANSWER - Phase describes the specific position of a
waveform in its cycle at a specific moment in
time and is expressed in angles (0, 90, 180, 270, 360 degrees)
• Starting phase - the point at which sound begins to vibrate
What type of interference happens when 2 sound waves with the same frequency are exactly 180
degrees out of phase? - CORRECT ANSWER - When 2 sound waves of the same
frequency that are 180 degrees out of phase interact, there is destructive interference and the two
waves will cancel each other out, resulting in
silence
