1. Which of the following best describes the subjective response of sound?
a) Objective and universal
b) Frequency and sound dependent
c) Constant for all individuals
d) Unaffected by environmental factors
Answer: b) Frequency and sound dependent
Explanation: The subjective response of sound varies among individuals and is influenced by factors such as frequency and sound characteristics.
2. What scale is commonly used to measure the intensity of sound?
a) Celsius scale
b) Decibel scale
c) Richter scale
d) Kelvin scale
Answer: b) Decibel scale
Explanation: The decibel scale is commonly used to measure the intensity of sound, representing the logarithmic ratio of sound pressure to a reference level.
3. What is the relationship between sound pressure level (SPL) and sound power level?
a) SPL is independent of sound power level
b) SPL is directly proportional to sound power level
c) SPL is inversely proportional to sound power level
d) There is no relationship between SPL and sound power level
Answer: b) SPL is directly proportional to sound power level
Explanation: Sound pressure level (SPL) is directly proportional to sound power level, as the intensity of sound influences the pressure experienced by the listener.
4. Which scale is used to analyze sound in octave bands?
a) Decibel scale
b) Richter scale
c) Octave band analysis scale
d) Kelvin scale
Answer: c) Octave band analysis scale
Explanation: Octave band analysis divides the frequency spectrum into octave bands to better understand the distribution of sound energy across different frequencies.
5. What is the purpose of weighting networks in measuring sound?
a) To increase the intensity of sound
b) To decrease the intensity of sound
c) To adjust for the sensitivity of the human ear
d) To eliminate sound distortion
Answer: c) To adjust for the sensitivity of the human ear
Explanation: Weighting networks are used to adjust measured sound levels to account for the varying sensitivity of the human ear across different frequencies.
6. What is the equivalent sound level?
a) The maximum sound level recorded
b) The average sound level over a specified period
c) The minimum sound level recorded
d) The peak sound level reached momentarily
Answer: b) The average sound level over a specified period
Explanation: Equivalent sound level represents the average sound level over a specified period, usually expressed in decibels.
7. Which type of noise exposure poses a risk of hearing damage?
a) Low-level intermittent noise
b) Moderate-level continuous noise
c) High-level transient noise
d) All of the above
Answer: d) All of the above
Explanation: All types of noise exposure, including low-level intermittent noise, moderate-level continuous noise, and high-level transient noise, can pose a risk of hearing damage depending on duration and intensity.
8. What are ear defenders used for?
a) To enhance hearing
b) To amplify sound
c) To protect the ears from noise
d) To improve sound quality
Answer: c) To protect the ears from noise
Explanation: Ear defenders are worn to protect the ears from exposure to excessive noise levels, reducing the risk of hearing damage.
9. What is the primary strategy for noise control at the source?
a) Using ear defenders
b) Sound enclosures
c) Acoustic barriers
d) Earplugs
Answer: b) Sound enclosures
Explanation: Noise control at the source often involves enclosing noisy machinery or equipment within soundproof enclosures to reduce sound emission.
10. How does industrial noise control differ from noise control in other environments?
a) Industrial noise control focuses on reducing sound at the receiver
b) Industrial noise control primarily involves using ear defenders
c) Industrial noise control addresses noise sources specific to industrial settings
d) Industrial noise control does not require specialized techniques
Answer: c) Industrial noise control addresses noise sources specific to industrial settings
Explanation: Industrial noise control involves addressing noise sources unique to industrial environments, such as machinery and equipment, through specialized techniques.
11. What is the purpose of semi-insert protectors?
a) To amplify sound
b) To block all external noise
c) To partially protect the ears from noise
d) To enhance hearing clarity
Answer: c) To partially protect the ears from noise
Explanation: Semi-insert protectors are designed to partially protect the ears from noise exposure while allowing some external sounds to be heard.
12. Which factor is crucial in determining the effectiveness of noise control along the path?
a) Sound pressure level
b) Distance from the noise source
c) Ambient temperature
d) Humidity level
Answer: b) Distance from the noise source
Explanation: The distance from the noise source is crucial in determining the effectiveness of noise control along the path, as sound intensity decreases with distance.
13. What is the primary purpose of earplugs?
a) To amplify sound
b) To block all external noise
c) To protect the ears from noise
d) To enhance hearing clarity
Answer: c) To protect the ears from noise
Explanation: Earplugs are inserted into the ear canal to block or reduce the entry of external noise, providing protection for the ears from noise exposure.
14. Which type of noise is most commonly associated with road traffic?
a) Low-frequency continuous noise
b) High-frequency intermittent noise
c) Moderate-frequency transient noise
d) Ultrasonic continuous noise
Answer: a) Low-frequency continuous noise
Explanation: Road traffic noise typically consists of low-frequency continuous noise generated by vehicle engines and tire friction on road surfaces.
15. What is the primary function of partitions in noise control along the path?
a) To block all sound transmission
b) To absorb sound energy
c) To redirect sound waves
d) To reduce sound transmission between spaces
Answer: d) To reduce sound transmission between spaces
Explanation: Partitions are used to reduce sound transmission between spaces by providing a physical barrier that obstructs the passage of sound waves.
16. Which type of noise exposure is considered hazardous?
a) Noise exposure below 50 decibels
b) Noise exposure above 85 decibels
c) Noise exposure between 60 and 80 decibels
d) Noise exposure exceeding 120 decibels
Answer: b) Noise exposure above 85 decibels
Explanation: Noise exposure above 85 decibels is considered hazardous and can lead to hearing damage if sustained over time.
17. What is the daily noise dose used to measure?
a) The maximum noise level reached in a day
b) The average noise level over a day
c) The cumulative noise exposure over a day
d) The minimum noise level recorded in a day
Answer: c) The cumulative noise exposure over a day
Explanation: The daily noise dose measures the cumulative noise exposure over a day, taking into account both the intensity and duration of exposure.
18. What is the primary objective of hearing conservation programs?
a) To eliminate all sources of noise
b) To reduce noise exposure to the lowest possible level
c) To amplify external sounds for better hearing
d) To enhance sensitivity to noise
Answer: b) To reduce noise exposure to the lowest possible level
Explanation: The primary objective of hearing conservation programs is to reduce noise exposure to the lowest possible level to prevent hearing damage and promote auditory health.
19. Which type of noise control focuses on reducing noise exposure at the receiver’s end?
a) Source control
b) Path control
c) Receiver control
d) All of the above
Answer: c) Receiver control
Explanation: Receiver control involves measures taken to reduce noise exposure at the receiver’s end, such as using ear defenders or implementing administrative controls.
20. What is the primary function of acoustic barriers in noise control?
a) To block all sound transmission
b) To absorb sound energy
c) To redirect sound waves
d) To reduce sound propagation to adjacent areas
Answer: d) To reduce sound propagation to adjacent areas
Explanation: Acoustic barriers are designed to reduce sound propagation to adjacent areas by obstructing the transmission of sound waves, helping to mitigate noise pollution.