" Which one of the following is not a technique for noise reduction at source?

Correct option is C

Ear-plugs or muffs are personal protective equipment (PPE) used to protect individuals from the effects of noise, but they do not reduce the noise produced by the source itself. Noise reduction at the source focuses on minimizing or controlling the noise where it originates. Techniques like using quieter machines, enclosing noisy machines in soundproof cases, and performing regular maintenance help reduce the noise generated by the machinery. Ear-plugs and muffs, on the other hand, are tools used to protect individuals from exposure to noise after it has already been produced.
Information Booster:
Reducing noise at the source is crucial for workplace safety, as prolonged exposure to high noise levels can lead to hearing loss and other health problems. Using quiet machines involves selecting equipment designed to operate at lower noise levels. Enclosing noisy machines within soundproof structures or barriers helps reduce the spread of noise to surrounding areas. Regular maintenance of machines ensures they run efficiently and quietly, as poorly maintained equipment often produces excessive noise due to wear and tear.
Additional Knowledge:
(a) Use of quiet machines: This is an effective method for reducing noise at the source. Modern machines are designed to operate quietly, which helps minimize noise pollution in industrial or work environments.
(b) Enclose noisy machines: Enclosing noisy machines in soundproof enclosures or using barriers is another common technique for reducing the spread of noise from the source to the surrounding environment.
(d) Regular maintenance of machines: Machines that are well-maintained generally produce less noise. Regular maintenance reduces the risk of parts malfunctioning, which can cause excessive noise.