Assertion (A) : Sound barriers alongside motorways in urban areas are very effective in controlling noise.
Reason (R) : They act as reflectors of sound back into motorways and upwards.
Choose the correct answer :
Assertion A: Sound Barrier Effectiveness
Sound barriers, often installed alongside major roads like motorways in urban areas, are designed specifically to reduce noise pollution. They work by creating an obstruction that blocks the direct path of sound waves traveling from the source (e.g., traffic) to receivers (e.g., homes). Therefore, the statement that they are very effective in controlling noise is generally considered true.
Reason R: Noise Reflection Mechanism
The effectiveness of sound barriers relies on how they interact with sound waves. Key mechanisms include:
- Reflection: Barriers bounce sound waves off their surface.
- Absorption: Some barrier materials absorb sound energy.
- Diffraction: Sound waves bend around the edges, but barriers aim to minimize this effect by being tall and continuous.
The statement mentions they act as reflectors back into motorways and upwards. This is a primary function; by reflecting sound away from sensitive areas, they reduce the noise experienced by people nearby. Reflecting sound back towards the motorway or upwards into the sky helps dissipate it harmlessly.
Analysis of Sound Barrier Explanation
Assertion (A) states that sound barriers are effective. Reason (R) explains the mechanism behind this effectiveness, highlighting their role as reflectors. The reflection and redirection of sound waves are indeed the main reasons why these barriers help control noise reaching residential areas. Therefore, Reason (R) provides a correct explanation for Assertion (A).
Conclusion
Both the assertion regarding the effectiveness of sound barriers and the reason explaining their reflective mechanism are correct. Furthermore, the reflective property described in Reason (R) is the primary way these barriers achieve the effectiveness mentioned in Assertion (A).
Correct Answer: Both (A) and (R) are correct and (R) is the correct explanation of (A).
Important Questions from Air and Noise Pollution - Teaching
Statement (I): The impact of Green House Gas emissions on the environment may comprise an accelerated increase in global warming as well as a significant rise in mean sea levels.
Statement (II) : Green House Gas omission is responsible for decreased landmasses, increased population densities, and food shortages.
Choose the correct statement from the following:
The equivalent noise level is significant for the following:
- Electrostatic Precipitator is used in Thermal Power Plants to remove which of the following air pollutants?
- What is Noise Induced Permanent Threshold Shifts (NIPTS) ?
If [$_env$ < [$_d$ ,where [$_env$ and [$_d$ are environmental & dry adiabatic lapse rates respectively ,which of the following types of plume emitted from a stack of a thermal power plant is observed ?
