Question

A brief exposure to 150 dB sound may
A. Damage eardrums
B. Cause permanent impairing hearing ability
C. Cause permanent impairing hearing ability
D. Both (A) and (B)

Answer 1

The decibel (symbol: dB) is a relative unit of measurement equal to one-tenth bel(B). It is used to express the ratio of one power or field quantity value to another, the logarithmic quantity being called the power level or field level, respectively, on a logarithmic scale.

Complete answer:
In decibels (dB), the sound is measured.
A whisper is about 30 dB, regular talk is about 60 dB, and it is about 95 dB for a motorcycle engine to run.
Noise over 70 dB can start to damage your hearing over a sustained period of time.
Loud noise above 120 dB will damage your ears instantly.
A short exposure to extremely high sound levels, produced by take-off of a jet plane or rocket, of 150 dB or more, can harm eardrums, thereby permanently impairing the ability to hear.
A single loud sound (like firecrackers) near your ear can result in hearing loss. Or, more commonly, hearing loss can result from damage caused by repeated exposure to loud noises over time. The louder the sound, the shorter the amount of time it takes to encounter hearing loss. The longer the exposure, the higher the risk of hearing loss (especially when hearing protection is not used or there is insufficient time between exposures for the ears to rest).
Thus the correct answer is option (D).

Note:
The decibel is mostly applied in acoustics and it is used as a unit of sound pressure level. The reference pressure in the air in this is set as the threshold value of perception of a human. The decibel is used to indicate the ratios of power /amplitude in arithmetic ratios in electronics. The total gain of a decibel can be calculated easily by adding all the decibel gains.