Question

What is the safe limit of sound level in dB for our ears?
A. Upto 12 dB
B. Upto 120 dB
C. Upto 180 dB
D. Upto 10dB

Answer 1

Hint: Ears are very sensitive to the high frequency of sound as this causes damage to the human ear over time. The safe limit of sound level must be less than the maximum audible sound range for the human ear.

Complete step by step answer:
Ears are a sensitive and very significant part of the human body. The human ear can only hear sounds of particular frequencies or pitches.
The Sound levels are measured using a logarithmic unit known as Decibel referred to as dB.
Hearing damage through sound is directly related to the amount of time spent listening to the sounds of a particular decibel as well. As per the World Health Organisation, the safe volume level of any sound for our ears is below 85 dB for maximum durations of eight hours. Anything above 85 dB for a prolonged duration of time can cause temporary damage to sensitive tissues of the ears or even permanent hearing loss.
For short durations of time, sounds up to a 120 dB are bearable and also considered safe by the world health organization, but again, listening to sounds at such high frequencies at regular intervals of stretched time durations is totally unsafe and makes the ears vulnerable to permanent hearing loss.
Noise Levels

Noise	Average Decibels (dB)
Leaves Rustling, soft music, whisper	15-30
Average Home Noise	40
Normal Conversation, Background Music	60
Office Noises, Inside Car at 60 mph	70
Vacuum Cleaner, Average Radio	75
Heavy Traffic, Window AC, Lawn Mower	80-89Sounds above 85 dB is harmful
Subway, Shouted Conversation	90-95
Motorcycle, Boom Box	96-100
Chainsaw	106-115
Rock Concert, Sports Crowd	120-129
Stock Car Races	130
Gunshots Police Sirens	140

Therefore, the correct option is B i.e., Upto 120 dB

Note: The loudness of a sound directly affects the amount of time one can listen to that sound. Additionally, similar to Temperature, the Sound frequency can go below zero as well. Humans can hear sounds as low as 0 dB and with very good hearing this can go lower to -15 dB as well.