Question

Write the name of the unit used to measure sound level.
A. Decibel
B. Hz
C. Watt
D. Joule

Answer 1

Hint: Sound is a form of energy and the sound intensity is a measurement take we take from what we hear,
Sound loudness is not necessarily the sound that enters the human ear, but it also tells of human ear sensitivity sensing the energy.

Complete step by step solution:
Loudness of sound is generally measured in decibel. The short form of decibel is written as $\text{dB}$.
One decibel is ten times the power-ratio of common logarithm. $1\text{dB}$ sound is very difficult to hear. No one can hear it if another sound is present in the background. It can only be heard with the help of a sine wave.
Sound loudness also depends on several variables such as pitch, sound emission size, ear response etc. The intensity of decibel may not remain the same on water and air. Decibel is not measured on a standard linear scale like other units. It is based on order of magnitudes. Decibel is mostly used in electronics.

Hence, option A is correct.

Option B is incorrect because $\text{Hz}$ or Hertz is a unit used for measuring frequency. It cannot be used to measure intensity of sound.
Option C is also incorrect because Watt is the unit of power.
Option D is not correct because Joule is the unit used to measure energy.

Note: Many people get confused because decibel may be used to describe power or intensity of other things also. Actually decibel is not like the common unit. It is a unit based on common logarithms. It is a way of relating a ratio on a scale. That ratio may be power or loudness of sound also.