Question

The sound level near a noisy air conditioner is 70 dB. If two such units operate side by side, the sound level near them would be

(a) 70 dB.

(b) 73 dB.

(c) 105 dB.

(d) 140 dB.

Short answer

The correct option is (b).

Step-by-step solution

Understanding sound level

Sound level refers to various logarithmic measurements of audible vibrations and may refer to sound exposure level, the measure of the sound exposure relative to a reference value. It is measured in decibels (dB), named in honor of Alexander Graham Bell, the inventor of both the telephone and the audiometer. Sound level is measured by an instrument called a decibel meter.

Explanation

A common misconception is to treat the sound intensity level as a linear scale instead of a logarithmic scale. If the sound intensity doubles, the intensity level increases by about 3 dB, so the correct answer is 73 dB.

Hence, the correct option is (b).