Noise

Question 1

Humans can hear from:

Answer 1

20 Hz to 20,000 Hz

Question 2

Speech range:

Answer 2

500 Hz to 3,000 Hz

Question 3

Amplitude in a sound wave means:

Answer 3

Loudness

Question 4

Po (reference pressure level) is

Answer 4

0.00002

Question 5

Io (reference intensity) AND Wo (reference power) is
*Wo is on equation sheet

Answer 5

10^-12

Question 6

The sound pressure level will decrease by ___ dB if you double the distance from the source

Answer 6

6

Question 7

OSHA: You are allowed __ dbA for 8 hours
Exchange rate:

Answer 7

90 dBA
5 dB

Question 8

ACGIH you are allowed ___ dBA for 8 hours
Exchange rate:

Answer 8

85 dBA
3 dB

Question 9

Tc=

Answer 9

Criterion time (8 hours for OSHA and ACGIH)

Question 10

Lc =

Answer 10

Criterion level (“PEL”)
OSHA- 90
ACGIH- 85

Question 11

Lt=

Answer 11

Threshold level (80 dB OSHA and ACGIH)
Below 80 dB the dosimeter does not count that level when estimating the dose

Question 12

ACGIH time OSHA
0.5
1
2
4
8
16

Answer 12

ACGIH time OSHA
97 0.5 110
94 1 105
91 2 100
88 4 95
85 8 90
82 16 85

Question 13

At which frequency is the frequency response attenuation level equivalent between the A, B, and C-weighting networks?

Answer 13

1000 Hz

Question 14

Directivity index:
-Free field
-On the floor
-Floor and wall
-In a corner

Answer 14

Free Field Q
Spherical 1
Hemisphere 2
Quadrant 4
Octant (corner) 8

Question 15

Which octave band has the greatest adjustment on the A-scale?

Answer 15

31.25 Hz

Question 16

The principle of detection employed by a sound level meter is best described as:

Answer 16

Direct measurement of sound pressures

Question 17

What is the ACGIH noise exposure limit for the 10-hour shift?

Answer 17

84 dBA

Question 18

Absorption material that is good for high frequencies:

Answer 18

Porous (foam, wool, fiberglass)

Question 19

Absorption material that is good for low frequencies:

Answer 19

diaphragmatic (nitrile, butyl, silicone)

Question 20

Frequencies tested on audiometric tests:

Answer 20

500, 1k, 2k, 3k, 4k, 6k

Question 21

What is considered a standard threshold shift:

Answer 21

Exceed 10 dB drop in 2k, 3k, or 4k Hz in either ear

Question 22

Sensorineural hearing loss often interferes with reception and interpretation of speech sounds by:

Answer 22

Making differentiation between high-frequency consonant sounds difficult

Question 23

Double hearing protection can add an extra __ dB

Answer 23

5

Question 24

Sensorineural hearing loss versus conductive hearing loss

Answer 24

Conductive hearing loss (CHL) results from physical obstructions or damage in the outer/middle ear (e.g., fluid, wax) preventing sound from reaching the inner ear, often treatable.

Sensorineural hearing loss (SNHL) involves damage to the inner ear (hair cells) or auditory nerve (cochlea), usually permanent, and is the most common type caused by aging or noise