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 medical imaging ultrasonic sound using ultrasound in medicine ultrasound and its applications

Three different vibrating objects produce three types of sounds X, Y and Z. Sounds X and Y cannot be heared by a man having normal range of hearing but sound Z can be heard easily. The sound X is used in hospital to break kidney stones of a patient into fine grains which then get flushed out with Urine. The sound similar to that which is produced during an earthquake before the main shock wave is generated.Name one device in our homes
which can produce sound like Z.

  1. oven

  2. Doorbell

  3. no such device is there in our homes

  4. all devices produce such sound
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

ultrasound is used for removing kidney stones.when ultrasound are targeted on such stone,the stones start vibrating at high frequency.the stone due to this vibratory motion. Breakdown into fine particles.ultrasounds and infrasounds are not audible to man.ultrasound have frequency more than 20kHz.a doorbell can produce an audible sound. Infrasound have frequency below 20Hz, X is ultrasound. Y is infrasound, Z is audible sound.

Multiple choice physics medical imaging ultrasonic sound using ultrasound in medicine ultrasound and its applications

Rats also play games by producing -------

  1. ultrasound

  2. infrasound

  3. audible sound

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

Frequencies higher than 20 kHz are called ultrasonic sound
or ultrasound. Ultrasound is produced by dolphins, bats and porpoises. Moths of certain families have very sensitive hearing equipment. These moths can hear the high frequency squeaks of the bat and know when a bat is flying nearby, and are able to escape capture. Rats also play games by producing ultrasound.

Multiple choice physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen. This is because:

  1. speed ofsound is greater than speed oflight

  2. speed of sound is equal to the speed of light

  3. speed of light is much greater than the speed of sound

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

It is because light travels faster  ($3\times10^{8}m/s$) than sound ($332m/s$) , so we hear thunder after a few second of the flash .

Multiple choice physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

Correct comparison between light waves and sound waves is:

  1. Both are mechanical waves

  2. Both need a material medium for propagation

  3. Both can travel through vacuum

  4. None
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Sound waves are mechanical waves, light waves are electromagnetic waves. Light can travel through vacuum, sound cannot.

Multiple choice physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

Light and Sound waves

  1. both are mechanical waves

  2. both need material media for propagation

  3. both can travel through vacuum

  4. are two different types of waves
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Sound waves are mechanical waves which are longitudinal in nature and require material media to pass through.

Light waves are electromagnetic waves which are transverse in nature and do not require any material medium to pass through.

Multiple choice physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

The thunder of a cloud is heard later compared to flash of lightning because :

  1. speed of sound is greater than speed of light

  2. speed of light is greater than speed of sound

  3. speed of sound is the same as speed of light

  4. sound is obscured by the rain
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The light travels much faster than the sound. The thunder travels at the speed of sound while the light from the flash travels at the speed of the light. The speed of light is about 340 m/s through air, while the speed of light is about 300 million m/s.So the thunder is heard after the flash of lightening.

Multiple choice physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

A worker lives at a distance of 1.32 km from the factory. If the speed of sound in air is 330 m$s^{-1}$, how long will the sound of factory siren take to reach the worker?

  1. 1 s

  2. 2 s

  3. 3 s

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

Given,


Distance $=1.32\,km=1320\,m$

Speed of sound in air $=330\,m/s$

We have,

$Time=\frac{Distance}{Speed}$

$Time=\frac{1320}{330}=4\,s$

Thus it would take $4\,s$ for the sound of the factory siren to reach the 
worker.