Noise Pollution MCQ Quiz in मल्याळम - Objective Question with Answer for Noise Pollution - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

The presence of excessive or unwanted sounds in the environment is called noise pollution. Major causes of noise pollution are sounds of vehicles, explosions including the bursting of crackers, machines, loudspeakers, etc. Television and transistor radio at high volumes, some kitchen appliances, desert coolers, air conditioner.

• It is defined as "unwanted or offensive sound that unreasonably interferes with our daily activities".
• Noise causes stress, leading to illness. Therefore any form of noise can be considered as pollution.
• Noise pollution is different from other types of pollution.  
• A person who is exposed to a loud sound continuously may get temporary or even permanent impairment of hearing.
• Unlike others, the sound is not a chemical but it is simply a wave motion in the air. So the noise pollution is a form of energy pollution. Pollution affects mostly the physical system, unlike noise pollution which affects physical as well as the mental systems. 

Noise Pollution can cause: 

• Apart from hearing loss, noise can cause annoyance, sleep disturbance, interference with communication, heartburn, indigestion, ulcers, high blood pressure, heart disease, and affects social behavior.
• Noise-induced stress creates severe tension in daily living and contributes to mental illness.
• People experiencing high noise levels (especially around airports or along road-rail corridors) differ from those with less noise exposure in terms of the increased number of headaches, greater susceptibility to minor accidents, increased reliance on sedatives and sleeping pills, increased mental hospital admission rates. 

Conclusion: Hence, Noise pollution can cause problems like sleeplessness, speech interference, an increase in blood pressure, a shift in threshold of hearing.

The correct answer is None of the Above

Key PointsSound Pollution:

• Noise pollution does not apply to all sounds.
• Noise pollution is defined by the World Health Organization (WHO) as noise that is louder than 65 decibels (dB).
• More specifically, noise becomes unpleasant over 120 decibels (dB) and hazardous above 75 dB.
•  Noise becomes a pollutant when its sound level increases beyond 80 dB. DB corresponds to decibels.
• The exposure of a person to such elevated levels can cause harm to humans; however, the intensity of the noise pollution depends on the intensity and exposure time.
• it is advised that noise levels be kept below 65 dB during the day.

Hence, sound pollution arises when sound waves exceed 80 decibels

The absolute threshold of hearing is the lowest sound level of a pure tone that a normal human ear can hear.

Key Points

• It's about the quietest sound a healthy young human can make.
• Hearing damage can be caused by long-term loud noise exposure.
• The body can also adapt to lower noise levels: external noise of 40 decibels (dBA) can disturb sleep.
• Human hearing thresholds are frequency-dependent.
• The quietest sound a young human with normal hearing can perceive at 1,000 Hz.
• it has been demonstrated that the ear's sensitivity is highest between 2 and 5 kHz.

Thus, Noise levels (db) are referenced to the human hearing threshold at a frequency of 1 kHz.

Additional Information

• The sound pressure generated by vibrations is converted into ossicle movements in our eardrums which are then sent to the inner ear as auditory sensations. 
• Its threshold can drop to as low as 9 dB SPL.

The correct answer is 10 dB

Key Points The Noise Pollution (Regulation and control) (Amendment) Rules, 2010

These rules provide the terms and conditions necessary to reduce noise pollution and allow the use of loudspeakers or public address systems at night (between 10:00 p.m. and 12:00 a.m.) on or during any cultural or religious celebratory event.

Following are the salient features of the amendment:

• At night, a loudspeaker, any sound producing device, or a sound amplifier may be used only in closed premises for internal communication, such as auditoriums, conference rooms, community halls, or banquet halls, or in the event of a public emergency.
• The noise level at the boundary of a public place where a loudspeaker or public address system is being used should not exceed 10 db above the ambient noise requirements of that region, or 75 db, whichever is lower.
• No horn shall be used in silence zones or residential areas at night except in emergency situations.
• Sound emitting construction equipments shall not be operated during night.
• In the heading ‘PUBLIC ADDRESS SYSTEM’ the words ‘AND SOUND PRODUCING SYSTEMS’ shall be inserted.

Noise pollution is considered to be any unwanted or disturbing sound that affects the health and well-being of humans and organisms. Loud noise can also cause high blood pressure, heart disease, sleep disturbances, and stress.

• According to the World Health Organization, sound levels less than 70 dB are not damaging to living organisms, regardless of the length or consistency of the exposure.
• The outdoor noise worldwide is mainly caused by machines, transport, and propagation systems.

According to a World Health Organization (WHO), Noise pollution causes harm to human health: -

• Hearing Problems
• Stress 
• Difficulty in Sleeping(Insomnia)
• Reduced Cognitive Functioning
• Cardiovascular Problems(heart disease)
• Emotion and Behavioral Change
• Reproduction Problems
• Trouble Communicating
• High blood pressure
• Reduced work efficiency

Noise pollution causes harm to animal health: -

• Reduction in Feeding Patterns
• Hearing Problems
• Hinders Communication
• Reproduction Problem
• Reduction in Production
• Behavioral Change
• Adaptation
• Slow Reaction Time
• Disturbs Echolocation in Sea Animals

Hence, we may say that Exposure to excessive noise pollution can cause: -

• Hearing impairment
• Insomnia
• The rise in blood pressure
• Reduced work efficiency

​Option (D) Respiratory disease is caused due air pollution, not due to noise pollution.

Key Points

Green Muffler scheme:

• Green Muffler is a technique of reducing noise pollution by planting 4-6 rows of plants around the populated areas or noisy places like along roadsides, industrial areas, societies near highways, etc. 
• These dense trees reduce noise pollution as they filter out the noise and obstruct it from reaching the citizens. 
• It is also a device for decreasing the amount of noise emitted by the exhaust of an internal combustion engine
• Under this scheme, Ashoka and Neem plants are planted near the house or resident localities to reduce noise pollution.

Important Points

Trees are known as noise buffers:

• They control noise pollution. Even urban noises are muffled by trees just like stone walls.
• An advantage of using plants as noise blockers is that they absorb sounds best in the high frequencies that people find annoying.
• Evergreen shrubs that too with broader leaves provide year-round noise protection so, they are best to plant. Trees absorb sound waves with their branches and foliage.
• According to USDA National Agroforestry Center, a properly designed buffer of trees and shrubs can reduce noise by about 10 decibels or about 5 0% as perceived by the human ear.

Thus, “Green Muffler” is related to noise pollution.

Key PointsThe CPCB has laid down the permissible noise levels in India for different areas. Noise pollution rules have defined the acceptable level of noise in different zones for both daytime and nighttime.

Hence, the correct answer is 55 dB.

Noise pollution:

• Noise pollution is that unpleasant sound that causes uneasiness to the ear and can lead to serious health hazards.
• It is more prevalent in metropolitan cities compared to suburban areas.
• Traffic is the main noise pollution in urban areas.

Features of Sound/Noise:

• A sound is a form of energy that causes the sensation of hearing. It is the main mode of communication.
• Sounds travel in the air or any other substance in the form of longitudinal waves. These waves are produced by the vibrations of the sound-producing source.

Noise levels decrease as we move away from the source of noise: Correct

• Sounds get louder as we move closer to the source and softer as we move away.
• In other words, noise levels decrease as we move away from the source of the noise.

​Materials with high surface/mass density act as good noise barriers: Correct

• Heavyweight structures with high mass transmit less sound energy than lightweight structures.
• The high density of heavyweight materials restricts the size of the sound vibrations inside the material.
• This high-density high-mass layer acts as a good noise barrier to the transmission of energy through the material.

Sound pressure of 2 Pa corresponds to the noise of zero decibels: Incorrect

• Sound Pressure (p) is the difference between the pressure caused by a sound wave and the static pressure of the media the sound wave is passing through.
• The unit of sound pressure is the pascal (Pa).
• Sound is measured in units called decibels.
• The softest sound that healthy ears can hear is 0 decibel (close to total silence).
• Sound pressure of 0.00002 Pa is equal to 0 dB.

Noise level refers to the measurement of the sound pressure in a particular environment. It is usually measured in decibels (dB) and provides a way to describe the loudness of a sound relative to a reference level. The reference level is often set at the threshold of human hearing, which is generally considered to be 0 dB.

A low noise level would correspond to a quiet environment such as a library, while a high noise level would correspond to a noisy environment such as a construction site. The noise level in a given environment can vary depending on many factors, including the source of the sound, the distance from the source, and the type of environment (e.g., an open field or a room with walls and a ceiling).

 Key Points

The decibel (dB) is a logarithmic unit of measurement that is used to express the magnitude of a signal, such as sound pressure or electrical power, relative to a reference level. The decibel is not an absolute unit of measurement, but rather a relative one that allows for the comparison of two signals.

Important Points

 A 20 dB increase in noise level represents an enhancement in the intensity of sound by a factor of 100. This is because dB is a logarithmic unit and a 20 dB increase corresponds to a factor of 10^(20/10) = 100.

So, a sound that is 20 dB louder than another sound is 100 times more intense. Similarly, a 40 dB increase in noise level represents a sound that is 10,000 times more intense than another sound, and so on.

Therefore, the correct answer is 100.

Option 1) 10 dB is the correct answer.

Reducing the intensity of noise by a factor of 10 will result in a reduction in noise level by 10 dB.

Important Points 

This is because the decibel (dB) scale is logarithmic, which means that a 10 dB increase corresponds to a ten-fold increase in sound intensity, while a 10 dB decrease corresponds to a ten-fold decrease in sound intensity. Therefore, reducing the intensity of noise by a factor of 10 corresponds to a 10 dB reduction in sound level.

The relationship between sound intensity (I) and sound level (L) is expressed in decibels (dB) using the following formula:

L = 10 log10(I/I0)

• where I0 is the threshold of human hearing, which is equal to 1x10^-12 W/m^2.
• When the intensity of a sound is reduced by a factor of 10, it means that the new intensity is one-tenth of the original intensity. Therefore, the new intensity (I') is equal to:
• I' = I/10
• Using the sound level formula, we can calculate the new sound level (L') by substituting the new intensity (I'):

L' = 10 log10(I'/I0) = 10 log10((I/10)/I0) = 10 log10(I/I0) - 10 log10(10) = L - 10 dB

So, reducing the intensity of noise by a factor of 10 results in a reduction of 10 dB in sound level.

• For example, if the initial sound level was 80 dB, reducing the intensity by a factor of 10 would result in a new sound level of 70 dB (i.e., 80 dB - 10 dB).
• Similarly, if the initial sound level was 90 dB, reducing the intensity by a factor of 10 would result in a new sound level of 80 dB (i.e., 90 dB - 10 dB)

Key Points 

Noise pollution is considered to be any unwanted or disturbing sound that affects the health and well-being of humans and organisms. Loud noise can also cause high blood pressure, heart disease, sleep disturbances, and stress

• Grades of ambient noise pollution are as follows according to noise pollution control and Regulations Rules 2000;
  • Industrial areas: 70-75 dB
  • Commercial areas: 55-65 dB
  • Residential areas: 45-55 dB
  • Silence zone: 40-50 dB
  • Indoor limit: <30 dB According to WHO
• Noise greater than 75 dB over long exposure can cause hearing damage.
• Noise above 120 dB can cause biochemical changes in human bodies.
• The decibel (dB) is a logarithmic unit used to measure sound level.
• It is also widely used in electronics, signals, and communication.
• In ordinary usage, the specification of the intensity of a sound implies a comparison of the intensity of the sound with that of a sound just perceptible to the human ear.
• In simple terms, the dB is the ratio between two power levels expressed in logarithmic terms in relation to some reference level.
• For example, if given two known power levels, P2 and P1, the relative value of P2 with respect to P1 in dB is given by:
  • dB = 10 log 10 (P2/P1)
• Noise levels below 35–40 dB are usually necessary for a good night’s sleep.
• A busy office may be about 60 dB while the noise level on a footpath beside a busy road might be approximately 75 dB.
• A departing jumbo jet may result in 120 dB being recorded along the runway.