Which of the following statements is INCORRECT?

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SSC JE Civil 07 Jun 2024 Shift 1 Official Paper - 1

The sound pressure of the faintest fastest sound that can be heard by a normal healthy individual is about 10 micropascals.
The sound pressure is expressed on a logarithmic scale. Sound level \(L=\log _{10} \frac{Q}{Q_0}\) Bels
Where Q = sound intensity, Qo = reference sound intensity
Measurements of the sound pressure on logarithmic scales are called levels.

Answer 1

Explanation:

Sound Pressure and Levels

Sound pressure is a measure of the force of sound waves on a surface area. It is usually measured in pascals (Pa) or micropascals (µPa).
To accommodate the wide range of sound pressures that can be heard by the human ear, sound pressure is often expressed on a logarithmic scale.
Sound levels are typically measured in decibels (dB), which are a logarithmic unit used to express the ratio of a given sound pressure to a reference sound pressure.

Evaluating the Statements

Statement 1: The sound pressure of the faintest sound that can be heard by a normal healthy individual is about 10 micropascals.

This statement is incorrect. Because One dB is equal to the faintest sound, a human ear can hear.

Statement 2: The sound pressure is expressed on a logarithmic scale. Sound level \(L = \log_{10} \frac{Q}{Q_0}\) Bels

This statement is correct. The sound level is \(L=\log _{10} \frac{Q}{Q_0}\) Bels(1 bel = 10 dB)

Statement 3: Where Q sound intensity, Qo reference sound intensity

This statement is correct. Q and Qo represent sound intensity and reference sound intensity, respectively, which aligns with the correct formula for calculating decibels.

Statement 4: Measurements of the sound pressure on logarithmic scales are called levels.

This statement is correct. Sound pressure levels are indeed measured on a logarithmic scale and referred to as levels, such as sound pressure levels in decibels (dB).