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

Human ears can sense sound waves travelling in air having wavelength of ________.

  1. ${10}^{-3}m$
  2. ${10}^{-2}m$
  3. $1 m$
  4. ${10}^{2}m$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Human ears can sense sound waves travelling in air whose frequencies $f$ lie in the range of $20Hz$ to $20kHz$

The average speed $v$ of sound in air is $335m/s$
Wavelength $\lambda=\cfrac vf$
Hence the wavelength range of audible sounds is $\cfrac{335}{20000}$  $to$  $\cfrac{335}{20}$
That is $1.675\times{10^{-2}}$ metres to $16.75$ metres
You can see that among all the 4 options given, only $1m$ fits in the audible range.

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

Voices of men, Women and children different because of

  1. The pitch

  2. The length and the thickness of vocal cords.

  3. Both

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

The voices of men, women and children differ from each other
due to the following factors:

i) The pitch is one of the most essential factors to determine the voice of the individual. For example, men have lower-pitched voices while women have higher-pitched voices.

(ii) Second factor which brings in the difference in the voices is the length and the thickness of vocal cords.  from each other due to the following factors

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

 State True or False.

All inaudible sounds produces frequencies less than 20 Hz.

  1. True

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

The frequency range of audible sound is $20 Hz$ to $20000 Hz$. Thus, the sound below the frequency 20 Hz is inaudible for human ear and the sound above the frequency 20000 Hz is inaudible for human ear. Thus, the given statement is false. 

Multiple choice meaning and elements of computer system computer in accounting accountancy

Human voice is an example of _______ signal.

  1. Analog

  2. Digital

  3. Electrical

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

Human voice is an example of Analog signal.

An analog signal is any continuous signal for which the time-varying feature (variable) of the signal is a representation of some other time varying quantity, i.e., analogous to another time varying signal.

Digital signals must have a finite set of possible values. ... That's the big difference between analog and digital waves. Analog waves are smooth and continuous, digital waves are stepping, square, and discrete.

So, in other words, if you're using a 56Kbps modem to access your Internet service provider (ISP), you have an analog connection from your home to the local exchange. But the ISP has a digital subscriber line (DSL) or a digital termination facility from its location to its exchange.

A signal is any kind of detectable quantity used to communicate information. An analog signal is a signal that can be continuously, or infinitely, varied to represent any small amount of change. Pneumatic, or air pressure, signals used to be used predominately in industrial instrumentation signal systems.

Multiple choice different modes of communication and their uses information technology communication systems physics

The difficulty to recognize the speaker's voice over the telephone is due to poor quality of sound.

  1. True

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

The bandwidth used to transmit telephone signals is very low , it is generally around $4 KHZ$ in range .So, the quality of audio signals is low , therefore make it difficult to recognize the speaker's voice .

In modern day technologies . the bandwidth of the audio signals is however increased to around $9 KHZ$

Multiple choice different modes of communication and their uses information technology communication systems physics

The sound waves in telephonic communication are converted into electric signals by the________ and the signals reach the _____________  at the other end by cables.

  1. mouthpiece,mouthpiece

  2. mouthpiece,earpiece

  3. earpiece,mouthpiece

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

The mouthpiece has a mic that converts the audio waves  from our voice to electric signals , that are carried further away to receiver .

The earpiece has a speaker ,A speaker converts the electric signal received to the audio wave .

Multiple choice different modes of communication and their uses information technology communication systems physics

The part of telephone instrument which is placed in front of mouth and collects sound and then propagates the information in the form of electromagnetic waves is called:

  1. Mouth-piece

  2. Receiver

  3. Cable wire

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The earpiece consists of an internal receiver that translates electronic signals into sound that a person can comprehend. On the other end of the handset is the mouthpiece, which consists of the transmitter. The transmitter is really a microphone that catches sound waves. The sound is then converted.  Hence the answer is mouth-piece.
Multiple choice social studies importance of transport system importance of transportation system introduction to transport and communication transportation services language, writing and great books

The constant sounds of vehicles create ________________.

  1. air pollution

  2. noise pollution

  3. water pollution

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

Noise pollution is caused by the loud and constant sounds generated by engines, horns, and traffic movement in urban areas.

Multiple choice physics spectra the electromagnetic spectrum electromagnetic spectrum electromagnetic waves

An ultrasound equipment work at frequency:

  1. Higher than $20,000 Hz $
  2. Higher than $10,000 Hz $
  3. Lower than 4420,000 Hz $
  4. Lower than $10,000 H _2 $
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. ultrasound devices operate with frequencies from 20000 Hz up to several gigahertz.

Multiple choice biology animal behaviour ethology natural selection coordination in human beings- chemical control endocrine system in humans

The highest sound frequency which a human being can detect is 20,000 vibrations/second. What is the highest frequency which a bat can detect?

  1. 75,000

  2. 50,000

  3. 10,000

  4. 150,000
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Most bats use frequencies in the range 20-80 kHz, only a few bats use frequencies less than 20 kHz.

So, the correct option is '75,000'.

Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

Heart sound which is longer is

  1. Lubb

  2. Dub

  3. Both are equal

  4. Sometimes (a) and sometimes (b).
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The first heart sound, 'Lubb', is caused by the closure of the atrioventricular valves. It is longer and lower in pitch compared to the second heart sound, 'Dub', which is caused by the closure of the semilunar valves.

Multiple choice physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

When sound wave is refracted from air to water, which of the following will remain unchanged?

  1. wave number

  2. wavelength

  3. wave velocity

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

Frequency of a wave is characterised by the source of wave, therefore it will not be affected by change in medium .