question_answer 23)

  The loudness of a sound that a person can withstand without discomfort is about (a) 150 dB                            (b) 215 dB                            (c) 30 d3                               (d) 80 dB

Answer:

                  (d) Relative loudness of sound ranges from 30 dB-60 dB and is generally not hazardous. The loudness above 60-80 dB, is not much uncomfortable while prolonged exposure to noise level above 80 dB is painful and gradually leads to permanent loss of hearing ability or deafness. The premissible sound level in different areas is shown in the following table

	Day	Night
Industrial Commercial Residential Silent	75 dB 65 dB 55 dB 50 dB	70 dB 55 dB 45 dB 40 dB