Unit of measurement for frequency (pitch) -Correct Answer Hertz (Hz)
Unit of measurement for intensity (loudness) -Correct Answer Decibel (dB)
Risk of damage from noise -Correct Answer How loud (intensity) and how long (duration)
Steady-state or continuous noise, e.g. generator -Correct An...
CAOHC Exam Study Questions and
Answers 2024-2025
Unit of measurement for frequency (pitch) -Correct Answer ✔Hertz (Hz)
Unit of measurement for intensity (loudness) -Correct Answer ✔Decibel (dB)
Risk of damage from noise -Correct Answer ✔How loud (intensity) and how long
(duration)
Steady-state or continuous noise, e.g. generator -Correct Answer ✔Lasts 1 second or
longer
Impulse or Impact noise, e.g. gunfire or nail gun -Correct Answer ✔Lasts less than one
second
Parts of the outer ear -Correct Answer ✔Pinna and external auditory canal
Parts of the middle ear -Correct Answer ✔Tympanic membrane, ossicles, eustachian
tube
Eustachian tube (auditory tube) -Correct Answer ✔Tube connecting the middle ear to
the pharynx and equalizes middle ear space with atmospheric pressure
Conductive HL occurs here -Correct Answer ✔Outer or middle ear
Sensorineural hearing loss -Correct Answer ✔Hearing loss resulting from damage to the
inner ear (cochlea) or the auditory nerve
Noise-induced hearing loss (NIHL) -Correct Answer ✔Condition caused by the
destruction of hair cells, the organs responsible for hearing, as a result of sounds that
are "too long, too loud, or too close"; a sensorineural hearing loss
Mixed hearing loss -Correct Answer ✔Combination of conductive and sensorineural
types in the same ear
Possible early symptoms/signs of noise induced hearing loss -Correct Answer
✔Tinnitus; difficulty understanding in presence of background noise; read visual cues
CAOHC Exam Study
, CAOHC Exam Study
Auditory effects of noise -Correct Answer ✔NIHL; tinnitus; hyperacusis
3 foot rule -Correct Answer ✔Good rule of thumb to recognize hazardous noise
exposure levels/situations: the rule is: if you have to shout at arms length (~3ft), in order
to be understood over the background noise, then you're likely exposed to hazardous
noise levels & should be wearing hearing protection to prevent NIHL
OSHA (Occupational Safety and Health Administration) versus National institute of
Occupational Safety and Heath (NIOSH) -Correct Answer ✔OSHA enforces regulation
and NIOSH recommends best practice based on science and research
Sound pressure level (SPL) versus hearing level (HL) -Correct Answer ✔SPL describes
noise measurements taken with a sound level meter or dosimeter; HL describes
Threshold levels obtained with an audiometer; 0 dB HL is not equal to 0 dB SPL
Noise Dosimeter -Correct Answer ✔A sound measurement device used to record the
amount of sound exposure over an extended period of
time (usually a work day)
Personal vs. Area
Sound level meter -Correct Answer ✔Uses a microphone to sense pressure variations
in sound waves; the meter converts those pressures directly into decibels; provides a
noise measurement that is a snapshot in time.
Time Weighted Average (TWA) -Correct Answer ✔An evaluation of exposures that is
time-weighted over an established period. It allow the exposure levels to be averaged
generally over an eight-hour time period.
OSHA exchange rate -Correct Answer ✔5 dB; for every 5 dB you go over the PEL of
90dBA TWA you half the allowable time of exposure
OSHA Action Level for noise -Correct Answer ✔85dBA TWA
Sound Level Meter A-weighted Scale -Correct Answer ✔OSHA requires this scale as it
resembles how the human ear responds to sound (humans hear best from 500 Hz to
4000 Hz
CAOHC Exam Study
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