Question

The degree of hearing loss due to noise pollution depends on which of the following?

I. Intensity of the sound
II. Duration of the noise
III. Amplitude of the sound

• A. I only
• B. II only
• C. I and II only
• D. I, II and III

Answer 1

The correct option is D I, II and III

Sound is a means of communication and entertainment. A loud, unwanted or unpleasant sound that causes discomfort is called noise. Undesired high levels of sound (noise) affecting the health and well being of organisms is called the noise pollution.

It has become a matter of concern as people are surrounded by the sound of vehicles, aircraft, industrial machines, loudspeakers, crackers etc. In day-to-day life noise can create too many ill effects.

One of the ill effects of noise pollution is the permanent or irreversible hearing loss. The degree of hearing loss depends on the following factors :

• Duration of the noise - It means the time or length of exposure of eardrums to the noise. Long exposure to loud noise can result in elevated blood levels which can cause hypertension and cardiovascular diseases in a normal person. For example, a brief exposure to extremely high sound levels like noise during a take off of a jet plane or rocket which is around 150 dB or more can permanently impair hearing ability.
• Intensity of sound - Intensity is a measure of the amount of energy in sound waves. The unit of intensity is the decibel (dB). Sounds that reach 85 decibels or higher can harm a person’s ears. It doesn't depend only on the duration but sometimes even for a small time of exposure the damage can be severe.
• Amplitude of the sound - It is the strength or level of sound pressure. The amplitude of a sound wave determines its loudness or volume. A larger amplitude means a louder sound, and a smaller amplitude means a softer sound. Hence option d is correct.