OHS 621 FINAL EXAM (6-11) QUESTIONS WITH CORRECT ANSWERS LATEST UPDATE
2025/2026
DEFINE Sound - Answers a) Produced in the air by 'oscillations' in air pressure (sound waves)
b) Converts into electrical signal & perceived as sensory experience by brain
How do sound waves BEHAVE? - Answers - Sound passes via solid, liquid, gas
- Can be reflected, diffracted, interfered
CHARACTERISTICS of Sound? - Answers Amplitude & Frequency
DEFINE Frequency/Pitch: - Answers - # of waves at ear per secs. OR # of cycles/secs. waves
move (measured in cps or hz)
- Wavelength or lambda (λ)
Frequency Waves (few/many) - Answers *FEW Waves = LOW Pitch
*MANY Waves = HIGH Pitch
Frequency (high/low wavelength) - Answers *HIGH Frequency = SHORT Wavelength
*LOW Frequency = LONG Wavelength
Frequency FORMU LA - Answers *F = C/λ*
- F = frequency of sound (cycles/sec.)
- C = speed of sound (m/sec.)
- λ = wavelength of sound (m)
How Fast Does Sound Travel? - Answers 344 m/sec. @20*C & 1100 ft./sec
DEFINE Amplitude - Answers "intensity or loudness" [measured in newtons per sq.m (m2) or
pascals (Pa)]
*1 Pa = 1 N/m2*
Amplitude (great amplitude = ?) - Answers GREATER Amplitude = LOUDER Sound
How much can the human ear hear? (amplitude) - Answers 0.00002 - 200 Pa
Amplitude (low/upper limit) - Answers *LOW Limit = threshold of HEARING
,*UPPER Limit = threshold of PAIN
DEFINE Soundwave - Answers pressure variations above/below atmospheric pressure
Amplitude Measurement Unit: (dB) - Answers - Loudness of sound is expressed in decibels (dB)
Sound Pressure Level (Lp) FORMULA : (Amplitude) - Answers *Lp = 20 log P/Po*
- Lp = sound pressure level (dB)
- P = sound pressure (Pa)
- Po = threshold of hearing of avg. person @1000 Hz (0.00002 Pa)
DEFINE Noise - Answers An unwanted, disagreeable, disturbing sound
OHS CONCERNS of Noise - Answers - Hearing loss
- Increased stress, nervousness, fatigue
- Interfere with speech/communication
- Synergic effects of VOC & CO
TYPES of Noise (3) - Answers 1) Continuous
2) Intermittent
3) Impact/Impulse (0.5 secs. with >1 sec. interval)
Ontario 85dB Exposure Level & Exchange Rate - Answers PEL = 85 dB for 8hrs.
Exchange Rate = 3 dB
Ontario 90dB Exposure Level & Exchange Rate - Answers PEL = 90 dB for 8 hrs.
Exchange Rate = 5 dB
DESCRIBE Noise Dosimeter: - Answers - Meter placed 9in. to ear/shoulder of worker to
determine personal exposure level
- Measures TWA of noise energy
COMPONENTS of Outer Ear (1) - Answers 1) PINNA: (ear flap)
- catch soundwave + increase ability to hear
, 2) EXTERNAL AUDITORY CANAL:
- filter particles + wax for infection protection
- leads to eardrum
- transmits energy to middle ear (from gas --> solid)
COMPONENTS of Middle Ear (2) - Answers 1) OSSICLES:
- contains malleus, incus, stapes
- vibration helps sound pressure to inner ear
- amplifies energy (220 - 1)
2) EUSTACHIAN TUBE:
- equalizes pressure on sides of eardrum + middle ear with external atmospheric pressure
COMPONENTS of Inner Ear (3) - Answers 1) OVAL WINDOW:
- attaches to 'stapes'
- fluid-filled + contains sensory receptors for hearing (cochlea) and balance (semicircular canal)
2) SEMICIRCULAR CANAL:
- body balance/position
- no impact on hearing
3) ORGAN OF CORTI: (cochlea)
- cochlea is responsible for sense of hearing
- fluid motions of inner ear are sensed + translates info. to nerve impulse
Where is HIGH FREQUENCY registered at in the inner ear? - Answers At base of cochlea + near
oval window
Where is LOW FREQUENCY registered at in the inner ear? - Answers At smaller end of cochlea
3 Networks Measurement Instruments Are Set To - Answers 1) Noise Dosimeter
2025/2026
DEFINE Sound - Answers a) Produced in the air by 'oscillations' in air pressure (sound waves)
b) Converts into electrical signal & perceived as sensory experience by brain
How do sound waves BEHAVE? - Answers - Sound passes via solid, liquid, gas
- Can be reflected, diffracted, interfered
CHARACTERISTICS of Sound? - Answers Amplitude & Frequency
DEFINE Frequency/Pitch: - Answers - # of waves at ear per secs. OR # of cycles/secs. waves
move (measured in cps or hz)
- Wavelength or lambda (λ)
Frequency Waves (few/many) - Answers *FEW Waves = LOW Pitch
*MANY Waves = HIGH Pitch
Frequency (high/low wavelength) - Answers *HIGH Frequency = SHORT Wavelength
*LOW Frequency = LONG Wavelength
Frequency FORMU LA - Answers *F = C/λ*
- F = frequency of sound (cycles/sec.)
- C = speed of sound (m/sec.)
- λ = wavelength of sound (m)
How Fast Does Sound Travel? - Answers 344 m/sec. @20*C & 1100 ft./sec
DEFINE Amplitude - Answers "intensity or loudness" [measured in newtons per sq.m (m2) or
pascals (Pa)]
*1 Pa = 1 N/m2*
Amplitude (great amplitude = ?) - Answers GREATER Amplitude = LOUDER Sound
How much can the human ear hear? (amplitude) - Answers 0.00002 - 200 Pa
Amplitude (low/upper limit) - Answers *LOW Limit = threshold of HEARING
,*UPPER Limit = threshold of PAIN
DEFINE Soundwave - Answers pressure variations above/below atmospheric pressure
Amplitude Measurement Unit: (dB) - Answers - Loudness of sound is expressed in decibels (dB)
Sound Pressure Level (Lp) FORMULA : (Amplitude) - Answers *Lp = 20 log P/Po*
- Lp = sound pressure level (dB)
- P = sound pressure (Pa)
- Po = threshold of hearing of avg. person @1000 Hz (0.00002 Pa)
DEFINE Noise - Answers An unwanted, disagreeable, disturbing sound
OHS CONCERNS of Noise - Answers - Hearing loss
- Increased stress, nervousness, fatigue
- Interfere with speech/communication
- Synergic effects of VOC & CO
TYPES of Noise (3) - Answers 1) Continuous
2) Intermittent
3) Impact/Impulse (0.5 secs. with >1 sec. interval)
Ontario 85dB Exposure Level & Exchange Rate - Answers PEL = 85 dB for 8hrs.
Exchange Rate = 3 dB
Ontario 90dB Exposure Level & Exchange Rate - Answers PEL = 90 dB for 8 hrs.
Exchange Rate = 5 dB
DESCRIBE Noise Dosimeter: - Answers - Meter placed 9in. to ear/shoulder of worker to
determine personal exposure level
- Measures TWA of noise energy
COMPONENTS of Outer Ear (1) - Answers 1) PINNA: (ear flap)
- catch soundwave + increase ability to hear
, 2) EXTERNAL AUDITORY CANAL:
- filter particles + wax for infection protection
- leads to eardrum
- transmits energy to middle ear (from gas --> solid)
COMPONENTS of Middle Ear (2) - Answers 1) OSSICLES:
- contains malleus, incus, stapes
- vibration helps sound pressure to inner ear
- amplifies energy (220 - 1)
2) EUSTACHIAN TUBE:
- equalizes pressure on sides of eardrum + middle ear with external atmospheric pressure
COMPONENTS of Inner Ear (3) - Answers 1) OVAL WINDOW:
- attaches to 'stapes'
- fluid-filled + contains sensory receptors for hearing (cochlea) and balance (semicircular canal)
2) SEMICIRCULAR CANAL:
- body balance/position
- no impact on hearing
3) ORGAN OF CORTI: (cochlea)
- cochlea is responsible for sense of hearing
- fluid motions of inner ear are sensed + translates info. to nerve impulse
Where is HIGH FREQUENCY registered at in the inner ear? - Answers At base of cochlea + near
oval window
Where is LOW FREQUENCY registered at in the inner ear? - Answers At smaller end of cochlea
3 Networks Measurement Instruments Are Set To - Answers 1) Noise Dosimeter
