Question

Sound above what level (decibel) is considered hazardous noise pollution:
1. 30 dB
2. 50 dB
3. 65 dB
4. 80 dB

Answer 1

Correct Answer - Option 4 : 80 dB

CONCEPT:

• Sound is a vibration that propagates through a medium in the form of a mechanical wave. The medium in which it propagates can either be a solid, a liquid, or a gas.
• Sound travels fastest in solids, relatively slower in liquids, and slowest in gases.
  • "A vibration that propagates as an audible wave of pressure, through a medium such as a gas, liquid or solid.
  • The reception of sound pressure waves and their perception by the brain.
  • The sound produced by a guitar is different from the sound produced by a drum. This is because the sound produced by different sources have different characteristics. Sound can be characterized by its frequency, wavelength, and amplitude.

EXPLANATION:

• Noise level is expressed on a logarithmic scale of decibels. The baseline noise levels in the community vary around 40 dB.
• International standards prescribe a maximum of 50 dB for the day and 40dB for the night in a residential area. Noise over 115 dB is regarded as highly avoidable.
• The World Health Organization (WHO) recommends an industrial noise limit of 75 dB and sound above 80 dB is considered hazardous noise pollution.