Physics · Science General

Acoustics and Sound Waves

2,160 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 physics sound time period, frequency and amplitude of sound amplitude, time period and frequency of a vibration nature and characteristics of sound waves

The sound produced by an object vibrating with a high frequency is called _____________ .

  1. shrill or high-pitched sound

  2. deep or low-pitched sound

  3. heavy sound

  4. musical sound
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The frequency determines the shrillness or pitch of a sound. If the frequency of vibration is higher, we say that the sound is shrill and has a higher pitch. If the frequency of vibration is lower, then we say that the sound has low pitch.

Multiple choice physics sound time period, frequency and amplitude of sound amplitude, time period and frequency of a vibration nature and characteristics of sound waves

State whether true or false :

Shrill sound is a high-pitch sound and a soft sound is a low-pitch sound.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The vocal cords of women are thicker than men , therefore they produce a shrill sound , which we know has higher frequency or higher pitch , whereas men's voice is grave , means low frequency i.e. lower pitch .

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

Fill in the blank.

When sound travels in a medium _______ travels in form of a wave.

  1. the source

  2. the particles of the medium

  3. the disturbance

  4. the medium
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When sound travels in a medium the disturbance travels in form of a wave.
Sound is produced when something vibrates. That is, a disturbance is produced. The vibrating body or disturbance causes the medium (water, air, etc.) around it to vibrate. Vibrations in air are called traveling longitudinal waves, which we can hear. Sound waves consist of areas of high and low pressure called compressions and rarefactions, respectively.

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

The sound waves in a medium are characterised by the

  1. linear motion of particle in the medium

  2. rotatory motion of particles in the medium

  3. oscillatory motion of particles in the medium

  4. none of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sound is a mechanical wave that results from the back and forth vibration of the particles of the medium through which the sound wave is moving. If a sound wave is moving from left to right through air, that is in an oscillatory motion, then particles of air will be displaced both rightward and leftward as the energy of the sound wave passes through it. 

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

Which of the following is NOT correct?

  1. more oscillation per second, higher time period

  2. greater amplitude greater loudness

  3. higher pitch, higher frequency of vibration

  4. more the value of decibel, higher is the noise
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Time period $T$ is defined as time taken to complete one oscillation , and frequency $f$ of a wave is defined as the number of oscillations per second ,

                     therefore , $T=1/f$  ,
which gives , more oscillations per second i.e. higher frequency , means smaller time period .

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

A person can be identified by the quality of sound produced by him. The characteristic of a sound can be determined by:

  1. amplitude

  2. frequency

  3. loudness

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The characteristics of a sound are :

(i) Loudness or intensity : it distinguishes between a loud or faint sound , and intensity , depends upon amplitude of sound waves .
(ii) Pitch : it distinguishes a sharp sound from a dull sound and pitch depends upon frequency.
(iii) Quality: it distinguishes between sounds generated by two sources .

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

Which of the following statement is NOT correct?

  1. loudness of sound is determined by the amount of energy received by the ear per unit time

  2. pitch doesn't depend upon the amount of energy

  3. loudness changes with change of frequency

  4. pitch changes with change in frequency
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Among all of the above only loudness changes with frequency is the wrong statement as loudness doesn't change with the change of frequency.

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

Which of the following statements is not true about a sound wave ?

  1. Sound travels faster in steel than in air

  2. Sound is a longitudinal wave

  3. The speed of sound in gas is not affected by a change in pressure of the gas

  4. The speed of sound in a gas decreases with increases in the temperature of the gas
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
A- Sound travel faster in solid than in gas. Here still is solid and air is gas.
B- Sound is a longitudinal wave as it can travels from one point to another point by to and fro.
C- Speed of sound in gas in independent of pressure and hence the answer.
D- The speed of the sound in a gas increases with the increasing in temperature of the gas. 
Hence D is incorrect ..
Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

Sound waves in the air don't show ______?

  1. Polarisation

  2. Diffraction

  3. Refraction

  4. Rreflection
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Answer is A.

Sound waves in air travel parallel to the direction that the particles within it oscillate it (definition of a longitudinal wave) - it propagates in 1 dimensional direction. Transverse waves have 2 components (and electric E component, and a magnetic M component). these components propagate at right angles to each other (i.e. it travels in two dimensions). Therefore it is possible to polarize transverse waves. 
Sound waves can be polarized in special conditions.In a solid medium, sound waves can be transverse waves, and in this scenario, the polarization is associated with the direction of the shear stress in the plane perpendicular to the propagation direction.
Hence, Sound waves in air do not show polarization.

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

Characteristic of sound which enables us to distinguish between two sound of same loudness and pitch :

  1. quality

  2. timbre

  3. amplitude

  4. a and b
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

 Quality is that characteristic of sound which enables us to distinguish between two sounds from two sources , even of the same frequency (pitch) and loudness . Quality is also called timbre . So option a and b are correct .