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

Audible vibrations have a frequency range of above 20,000 Hz. True or false.

  1. True

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

The human hear can respond to minute pressure variations in the air if they are in the audible frequency range, roughly 20 Hz to 20,000 Hz. The vibrations above or below this range is not audible by human.

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

We can hear sound of frequency -

  1. 1 Hz

  2. 100 Hz

  3. 10 Hz

  4. 40,000 Hz
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Humans cannot hear sound of every frequency. The range of hearing for a healthy young person is 20 Hz to 20,000 Hz. This is called audible range of frequency. So, human can hear sound of frequency 100 Hz.

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

The sounds that cannot be heard by humans are 

  1. inaudible sounds

  2. infrasounds

  3. ultra sounds

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

Humans can hear sounds having frequencies between the range of $20\ Hz$ and $20,000\ Hz$. The sounds above and below this range are inaudible to humans. The sounds below the range of $20\ Hz$ are called infrasounds and the sounds above the range of $20,000\ Hz$ are called ultrasounds. Both are inaudible to humans.

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

Which of the following sounds are not audible?

  1. a tuning fork vibrating 400 times in 2 sec.

  2. a tuning fork vibrating 3600 times in 60 s.

  3. tuning fork vibrating 1 time in 1 sec

  4. tuning fork vibrating 900 times in 2 sec
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The range of audible frequency is 20 Hz - 20,000 Hz.
In the first case frequency of the tuning fork will be 200 Hz. 
In second case it will be 60 Hz.
In third case frequency will be 1 Hz ,which is out of the audible frequency range.

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

Why we can hear the sound produced by bees but we cant hear the sound of vibrations of pendulum?

  1. Sound of vibrations of pendulum is in audible rays

  2. Sound of bees are in audible range

  3. Sound of bees are in infrasonic range while sound of vibrations of pendulum are in ultrasonic range

  4. None is true
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sound of vibrations of pendulum lies in infrasonic range while sound of bees lies in audible range.

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

Range of frequency of ultrasound is:

  1. 2 kHz - 106 Hz

  2. 25 kHz - 1015 Hz

  3. 2 kHz - 1010 Hz

  4. 20 kHz - 107 Hz
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The frequency of ultrasonic wave is greater than 20,000 Hz and equal to 107 Hz. These waves are not audible to a human ear but they can be heard by animals and birds.

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

If a vibration is produced 200 times per second.

  1. It will be audible by the human ear

  2. It would not be audible by the human ear.

  3. It depends on its amplitude.

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

It will be audible by the human ear because vibration is produced 200 times/second.
So,frequency = 200 Hz
And the range of audible frequency is 20 Hz - 20,000 Hz.

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

Which of the following frequency of sound can be heard by a dog but not by a man?

  1. 50,000 hertz

  2. 15,000 hertz

  3. 1200 hertz

  4. none
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A sound of frequency 50,000 hertz can be heard by a dog but not by a man. The waves having frequency between 20 Hz - 20,000 Hz are audible frequency of waves.

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

Which kind of sound is produced in an earthquake before the main shock wave begins?

  1. ultrasonic sound

  2. infrasonic sound

  3. audible sound

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

Infrasonic waves are waves whose frequency is below 20Hz. These sounds are not heard by human ears. Audible sounds are between 20 Hz and 20,000 Hz.

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

Bats detect the obstacle in their path by receiving the detected:

  1. infrasonic waves

  2. ultrasonic waves

  3. both

  4. none
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Bats can produce ultrasonic waves by flapping their wings.
They can also detect these waves.these waves produced by the bats after reflection from the obstacles like building guide them to  remain away from the obstacles during night with the help of ultrasonic waves.

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

Three different vibrating objects produce three types of sounds X, Y and Z.
Sounds X and Y cannot be heard by a man having normal range of hearing but sound Z can be heard easily.
The sound X is used for echocardiography.The sound similar to that which is produced during an earthquake before the main shock wave is generated.
Name one device in a science laboratory which can produce sound like Y.

  1. simple pendulum.

  2. tuning fork

  3. glass

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

Ultrasound is used in echocardiography. In this ultrasound are used to construct the image of heart. Ultrasounds and infrasounds are not audible to man. Ultrasound have frequency more than 20 kHz.
Infrasound have frequency below 20 Hz.
Y is infrasound .

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

Which of the following sounds is not audible?

  1. A tuning fork vibrating 400times in 2s

  2. A tuning fork vibrating 3600 times in 60s

  3. Tuning fork vibrating 1time in 1 s

  4. Tuning fork vibrating 900 times in 2s
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The range of audible frequency is 20 Hz to 20,000 Hz. In the first case frequency of the tuning fork will be 200Hz. In second case it will be 60Hz and In third case frequency will be 1 Hz ,which is out of the audible frequency range. In fourth case frequency is 450 Hz which is again in the audible range.

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

Rats also play games by producing __________.

  1. ultrasonic sound

  2. infrasonic sound

  3. audible sound

  4. all of the above
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.