Physics · Science General

Acoustics and Sound Waves

2,006 Questions

Acoustics and sound waves deal with mechanical vibrations traveling through media like air and water. Key concepts include wave reflection, beats, echoes, the Mach number, and infrasound. These physics fundamentals are regularly tested in general science sections of multiple competitive exams.

Sound wave propagationEchoes and reflectionWave interferenceMach numberInfrasound frequency

Acoustics and Sound Waves Questions

Multiple choice audible, infra and ultra sound with its application study of sound physics

The audible range of a person is 20 to 20,000 Hz. If the speed of sound in air is $\displaystyle 330{ ms }^{ -1 }$, calculate the longest wavelength of sound, which he can detect?

  1. $\displaystyle \frac { 18000 }{ 330 } m$
  2. $\displaystyle \frac { 330 }{ 1800 } m$
  3. $\displaystyle \frac { 20 }{ 330 } m$
  4. $\displaystyle \frac { 330 }{ 20 } m$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

We have the formula,


$V=\lambda\times v$

where,

$V$ is the velocity of sound $= 330ms^{-1}$

$v$ is the frequency

$\lambda$ is the wavelength

We have a range of frequencies from $20\,Hz$ to $20,000\,Hz$

Hence for frequency $v=20\,Hz$, we have 

$330=20\times \lambda$

Therefore, $\lambda=\dfrac{330}{20}\,m$

Multiple choice audible, infra and ultra sound with its application study of sound physics

Which one of the following sound frequencies can be heard by a human ear?

  1. 10 Hz

  2. 15 Hz

  3. 30,000 Hz

  4. 15,000 Hz
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The audible frequency range for human ear is from 20Hz to 20,000Hz , as out of the given frequencies , only frequency of 15000Hz lies in audible range , therefore it can be heard by human ear .

Multiple choice audible, infra and ultra sound with its application study of sound physics

When mechanical waves have a frequency below the audible range, these are called

  1. sonics

  2. infrasonics

  3. ultrasonic

  4. supersonic
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Waves can be categorised on the basis of frequency as :

(1) Sonicwaves- having frequencies , ranging from 20Hz to 20,000Hz , this is the audible range for human ear.
(2) Infrasonicwaves- having frequencies , below 20Hz (below audible range) .
(3) Ultrasonicwaves- having frequencies , above 20,000Hz .
Supersonic waves are related to the speed of wave , waves having speed greater than speed of sound in air .

Multiple choice audible, infra and ultra sound with its application study of sound physics

What is the audible range of sound? 

  1. 0 - 200 Hz

  2. 0 - 20,000 Hz

  3. 20 - 20,000 Hz

  4. 30.0 to 2000 Hz
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Answer is C.

The generally accepted standard range of audible frequencies is 20 Hz to 20,000 Hz, although the range of frequencies individuals hear is greatly influenced by environmental factors. 

Multiple choice audible, infra and ultra sound with its application study of sound physics

Out of the following, which frequency is not clearly audible to the human ear?

  1. 30 Hz

  2. 30,000 Hz

  3. 300 Hz

  4. 3000 Hz
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A person who has hearing within the normal range can hear sounds that have frequencies between 20 Hz to 20,000  Hz. This frequency range is called audible frequency range. Since the frequency 30,000 Hz is above the audible frequency range human ear cannot audible it clearly.

Multiple choice audible, infra and ultra sound with its application study of sound physics

The audible range of frequency is

  1. 20 Hz to 20,000 Hz

  2. 40 Hz to 40,000 Hz

  3. 60 Hz to 60,000 Hz

  4. 10 Hz to 20,000 Hz
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Human ear can hear sound having frequency range from $20 \ Hz$ to $20 \ kHz$.

So, human beings can't hear sound having frequency below $20  \ Hz$ and above $20,000 \ Hz$.

Multiple choice audible, infra and ultra sound with its application study of sound physics

Out of the following, which frequency is not clearly audible to the human ear ?

  1. $30\;Hz$
  2. $30,000\;Hz$
  3. $300\;Hz$
  4. $3000\;Hz$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The frequency range of human hearing is about 20 Hz to 20 KHz. This range of frequency is known as audible range. Human cannot hear the sound with frequency above or below this audible range. Hence the sound with frequency 30,000 Hz cannot audible to human ear