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Flashcards in Noise Deck (33)
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1
Q

What is noise?

A

Undesirable or unwanted sound

Subjective

2
Q

What is noise propagation?

A

Generated at a source and spreads spherically away from that source
Diminished with distance and loses engery

3
Q

What occurs as “sounds waves” when objects are encountered?

A

Bending and diffraction

4
Q

How is sound measured logarithmically?

A

bel (B)

5
Q

What is the more commonly used subunit for sound?

A

Decibel (dB)

1/10 bel

6
Q

The power of a sound wave is proportional to the…..

A

Square of the pressure

7
Q

Combinations of sounds may make ____ in the decibels.

A

Little

8
Q

At what level would a person receive painless damage?

A

85-125 dB

9
Q

At what level would a person start to feel pain?

A

Over 125 dB

10
Q

Frequency

A

Vibrating object moves molecules back and forth causing sound waves to move outward

11
Q

What is the range of normal hearing?

A

20 Hz to 20 kHz

12
Q

Steady frequencies

A

Pure tones

Tuning forks and electronic oscillators Uncommon

13
Q

Intensity

A

Directly proportional to sound pressure

Pascals (Pa) and micropascals (uPa)

14
Q

What is the normal range for intensity?

A

20 uPa to 20 Pa

15
Q

What is the A scale?

A

Sound measurement as an approximation of the sensitivity of the human ear
2 sounds with the pressure lvl may have different A levels

16
Q

Steady noises

A

Continuous, intermittent, impulse

17
Q

What are the effects of noise to the outer ear?

A

Minimal direct effects, possible physical damage to pinna or ear with small effects
Restriction of ear canal with cerumen causing mild to moderate hearing loss

18
Q

What are the effects of noise to the middle ear?

A

Effects due to the acoustic reflex of involuntary contractions in the ossicular chain due to high-intensity sound
Overtime stiffening of the chain impairing low frequency sounds

19
Q

What can occur if there is fluid in the middle ear and what else could cause this?

A

May produce mild to moderately severe hearing loss
Perforated ear drum
Fixed or disconnected ossicles

20
Q

What are the effects of noise to the inner ear ?

A

Sensorineural
Exposure to loud noise may produce temporary threshold shifts (may become permanent)
Intense bursts may cause permanent damage immediately

21
Q

Describe the cochlea.

A

Hair cells that change mechanical fluid vibrations into nerve impulses
Base: high frequencies
Apex: low frequencies
Inner hair: all sounds

22
Q

Presbycusis

A

Slow loss of hearing due to age

23
Q

What are some causes of age-related hearing loss?

A

Familial, repeated exposure to loud noises, smoking, medical conditions or medications

24
Q

What are the symptoms of age-related hearing loss?

A

Sounds may seem overly loud
Difficulty hearing things in noisy areas
HIgh pitches sounds like s or th may be hard to distinguish
Men’s voices easier to hear, some people sound slurred
Tinnitus

25
Q

What are some steps to help age-related hearings loss?

A

No cure
Hearing aids
Telephone amplifiers and other assertive devices
Sign language or speech reading

26
Q

Describe a cochlear implant.

A

Must have a functioning auditory nerve
Restores a sense of hearing, not actual ability to hear
Makes sounds louder
Should be considered in those with relatively short-term total hearing loss

27
Q

What are some other effects of noise?

A

Reduced ability to communicate, in BP, changes in hormone production, sleep disturbances, behavioral changes, dec task performance

28
Q

What are some way transport sources help control “environmental” noises of cars?

A

Noise barriers around road, sleep limits, highway surface texture, vehicle limits, tire design

29
Q

What are some way transport sources help control “environmental” noises of aircrafts?

A

Engine design, sound attenuation packages, alteration of flight path direction and timing

30
Q

Occupational noise has more…

A

Specific data and methods of control

31
Q

What are the OSHA standards?

A

85 dB = 8 hr time weighted average (TWA)
Each 4 dB rise dec time exposed by half;
85 db = 8 hrs
89 db = 4 hrs

32
Q

What scale does OSHA use for noise monitoring?

A

A scale

33
Q

When should a person wear hearing protectors?

A

Over 85 dB or impulse noise over 140 dB

Double protection needed at 108 dB