BUILDING UTILITIES 3 LIGHTING AND
ACOUSTICS EXAM QUESTIONS AND
ANSWERS
SOUND - Answer-Sensation stimulated in the organs of hearing by mechanical radiant
energy transmitted as longitudinal pressure waves through the air or other medium.
SOUND WAVES - Answer-A longitudinal pressure wave in air or an elastic
medium ,esp. one producing an audible sensation.
WAVE - Answer-a disturbance or oscillation that transfers energy progressively from
point to point in a medium or space without advance by the points themselves , as in the
transmission of sound or light.
WAVEFORM - Answer-A graphic representation of the shape of a wave, obtained by
plotting deviation at a fixed point versus time.
WAVELENGTH - Answer-The distance, measured in the direction of the propagation of
a wave, from any one point to the next point of corresponding phase.
PHASE - Answer-A particular point or stage in a periodic cycle or process
AMPLITUDE - Answer-The maximum deviation of a wave or alternating current from its
average value
FREQUENCY - Answer-The number of cycles per unit time of a wave oscillation.
HERTZ - Answer-the SI unit of frequency, equal to one cyce per second.
PITCH - Answer-The predominant frequency of a sound as perceived by the human
ear.
WAVE FRONT - Answer-A surface of a propagating wave composed at any instant of
all points having identical phase, usually perpendicular to the direction of propagating.
FUNDAMENTAL - Answer-the lowest frequency at which a vibrating element or system
will freely oscillate. Also called fundamental frequency.
HARMONIC - Answer-A vibration having a frequency that is an integral multiple of that
of the fundamental
BAND - Answer-A range of wavelength or frequency between two defined limits
, OCTAVE - Answer-The interval between two frequencies having a ratio of 2:1
DOPPLER EFFECT - Answer-An apparent shift in frequency occurring when an
acoustic source and listener are in motion relative to each other, the frequency
increasing when the source and listener approach each other and decreasing hen they
move apart.
1087ft(.3km) per second - Answer-velocity of sound in air
4500ft(1.4km) per second - Answer-velocity of sound in water
11,700ft(3.8km) per second - Answer-velocity of sound in wood
18000ft(5.5km) per second - Answer-velocity of sound in steel
loudness - Answer-a subjective response to sound indicating the magnitude of the
auditory sensation produced by the of a sound wave.
phon - Answer-a unit for measuring the apparent the loudness of a sound, equal in
number to the decibels of a 1000-Hz reference sound judged by a group of listeners to
be equal in loudness to the given sound.
sone - Answer-a unit for increasing the apparent loudness of a sound judged by a group
of listeners to be equal to the loudness of a 1000-Hz reference sound having an
intensity of 40 decibels.
equal loudness contour - Answer-a curve representing the sound pressure level at
which the sounds of the different frequencies are judged by a group of listeners to be
equally bond.
decibels - Answer-a unit for expressing the relatives pressure or intensity of sounds on
a uniform scale from 0 for the least perceptible sound to about 130 for the average
threshold of pain.
hearing - Answer-the sense by which sound is perceived involving the entire
mechanism of the internal, middle, and external ear and including the nervous and
cerebral operations that translate the physical operations into meaningful signals.
threshold of pain - Answer-the level of sound intensity high enough to produce the
sensation of pain in the human ear, usually around 130 dB.
auditory fatigue - Answer-physical or mental weariness caused bu the prolonged
exposure to loud noises.
hearing loss - Answer-an increase in the threshold of the audibility at specific
frequencies caused by the normal aging disease, or injury to the hearing organs.
ACOUSTICS EXAM QUESTIONS AND
ANSWERS
SOUND - Answer-Sensation stimulated in the organs of hearing by mechanical radiant
energy transmitted as longitudinal pressure waves through the air or other medium.
SOUND WAVES - Answer-A longitudinal pressure wave in air or an elastic
medium ,esp. one producing an audible sensation.
WAVE - Answer-a disturbance or oscillation that transfers energy progressively from
point to point in a medium or space without advance by the points themselves , as in the
transmission of sound or light.
WAVEFORM - Answer-A graphic representation of the shape of a wave, obtained by
plotting deviation at a fixed point versus time.
WAVELENGTH - Answer-The distance, measured in the direction of the propagation of
a wave, from any one point to the next point of corresponding phase.
PHASE - Answer-A particular point or stage in a periodic cycle or process
AMPLITUDE - Answer-The maximum deviation of a wave or alternating current from its
average value
FREQUENCY - Answer-The number of cycles per unit time of a wave oscillation.
HERTZ - Answer-the SI unit of frequency, equal to one cyce per second.
PITCH - Answer-The predominant frequency of a sound as perceived by the human
ear.
WAVE FRONT - Answer-A surface of a propagating wave composed at any instant of
all points having identical phase, usually perpendicular to the direction of propagating.
FUNDAMENTAL - Answer-the lowest frequency at which a vibrating element or system
will freely oscillate. Also called fundamental frequency.
HARMONIC - Answer-A vibration having a frequency that is an integral multiple of that
of the fundamental
BAND - Answer-A range of wavelength or frequency between two defined limits
, OCTAVE - Answer-The interval between two frequencies having a ratio of 2:1
DOPPLER EFFECT - Answer-An apparent shift in frequency occurring when an
acoustic source and listener are in motion relative to each other, the frequency
increasing when the source and listener approach each other and decreasing hen they
move apart.
1087ft(.3km) per second - Answer-velocity of sound in air
4500ft(1.4km) per second - Answer-velocity of sound in water
11,700ft(3.8km) per second - Answer-velocity of sound in wood
18000ft(5.5km) per second - Answer-velocity of sound in steel
loudness - Answer-a subjective response to sound indicating the magnitude of the
auditory sensation produced by the of a sound wave.
phon - Answer-a unit for measuring the apparent the loudness of a sound, equal in
number to the decibels of a 1000-Hz reference sound judged by a group of listeners to
be equal in loudness to the given sound.
sone - Answer-a unit for increasing the apparent loudness of a sound judged by a group
of listeners to be equal to the loudness of a 1000-Hz reference sound having an
intensity of 40 decibels.
equal loudness contour - Answer-a curve representing the sound pressure level at
which the sounds of the different frequencies are judged by a group of listeners to be
equally bond.
decibels - Answer-a unit for expressing the relatives pressure or intensity of sounds on
a uniform scale from 0 for the least perceptible sound to about 130 for the average
threshold of pain.
hearing - Answer-the sense by which sound is perceived involving the entire
mechanism of the internal, middle, and external ear and including the nervous and
cerebral operations that translate the physical operations into meaningful signals.
threshold of pain - Answer-the level of sound intensity high enough to produce the
sensation of pain in the human ear, usually around 130 dB.
auditory fatigue - Answer-physical or mental weariness caused bu the prolonged
exposure to loud noises.
hearing loss - Answer-an increase in the threshold of the audibility at specific
frequencies caused by the normal aging disease, or injury to the hearing organs.
