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

Why are sound waves considered as mechanical waves?

  1. The sound wave is a disturbance that is transported through a medium.

  2. The particles of sound waves vibrate in a direction perpendicular to the direction of propagation of wave.

  3. The particles of sound waves always tend to come back to their original positions when set in wave motion.

  4. All of the above

  5. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Yes, it is the correct reason.

Multiple choice

The velocity of sound in any gas depends upon

  1. the wavelength of sound only

  2. the density and elasticity of the gas

  3. the intensity of sound waves only

  4. the amplitude and frequency of sound
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The velocity of sound in any gas depends upon the density and elasticity of the gas. 

Multiple choice

Which one of the following statements is wrong?

  1. Sound travels in a straight line.

  2. Sound travels as a wave.

  3. Sound is a form of energy.

  4. Sound travels faster in vacuum than in air.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Sound is a mechanical wave that requires a medium, such as air, water, or solid matter, to propagate. Because a vacuum contains no particles to transmit vibrations, sound cannot travel through it at all. Therefore, the statement that sound travels faster in a vacuum is false.

Multiple choice

An astronaut cannot hear his companion at the surface of the moon because

  1. the produced frequencies are above the audio frequency.

  2. there is no medium for sound propagation.

  3. the temperature is too low during night and too high during day.

  4. there are too many craters on the surface of the moon.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sound waves are mechanical and require a medium like air to travel from one point to another. Since the moon has no atmosphere, there is no medium to carry the sound vibrations, making it impossible to hear speech through the open environment. Astronauts must use radio sets to communicate instead.

Multiple choice

Velocity of sound is

  1. lesser in moist air than in dry air

  2. greater in moist air than in dry air

  3. same in moist and dry air

  4. independent of humidity in air
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Moist air is actually less dense than dry air because water vapor molecules are lighter than the nitrogen and oxygen molecules they displace. Since the speed of sound is inversely proportional to the square root of the density of the gas, sound travels faster in humid conditions. This means sound velocity increases as humidity increases.