Brief exposure to the sound of minimum __________ can damage ear drums of humans.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 150 dB
Option (3) 150 dB — Correct. NCERT gives 150 dB or more as the level at which even a brief exposure may damage the ear drums and permanently impair hearing. Such noise comes from the take-off of a jet plane or rocket.
Note: This question is from Chapter 16, Environmental Issues, of the pre-rationalised NCERT book. This chapter is not in the present NCERT book (2026-27). The extract below is from the pre-rationalised edition.
NCERT Extract (Pre-rationalised edition, Chapter 16, Environmental Issues):
Air Pollution and Its Control – “… In India, the Air (Prevention and Control of Pollution) Act came into force in 1981, but was amended in 1987 to include noise as an air pollutant. Noise is undesired high level of sound. We have got used to associating loud sounds with pleasure and entertainment not realising that noise causes psychological and physiological disorders in humans. The bigger the city, the bigger the function, the greater the noise!! A brief exposure to extremely high sound level, 150 dB or more generated by take off of a jet plane or rocket, may damage ear drums thus permanently impairing hearing ability.”