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

Pitch describes how fast an object is

  1. vibrating

  2. stopping

  3. spinning
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Pitch is directly related to the frequency of vibration; faster vibrations produce higher-pitched sounds, while slower vibrations produce lower-pitched sounds.

Multiple choice

THD (Audio)

  1. Total Harmonic Distortion

  2. Total Harmonica Distortion

  3. Tonal Harmonic Distortion

  4. Tonal Harmonic Display
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

THD stands for Total Harmonic Distortion, a measurement of the harmonic distortion present in a signal, commonly used in audio equipment specifications.

Multiple choice

Your ears may pop on an airplane because pressure is moving from

  1. high to low

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

As an airplane climbs, the cabin pressure decreases, moving from high to low pressure. The air trapped in your inner ear is at a higher pressure, and it pushes outward to equalize with the lower pressure outside, causing your ears to pop.

Multiple choice

Empty vessels make the (         ) sound.

  1. most

  2. more

  3. much

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

This question tests the completion of a well-known English proverb, "Empty vessels make the most sound" (or "noise"). The superlative adjective "most" is used here to complete the idiom, which means that people who know the least often talk the most. Other options like "more", "much", or "many" do not fit the standard idiomatic phrasing.

Multiple choice polarisation of light polarisation wave optics optics physics

Which of these waves can be polarised ?

  1. Sound waves

  2. Longitudinal waves on a string

  3. Transverse waves on a string

  4. Light waves
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • Only transverse waves can be polarised. Longitudinal waves (sound waves in air) cannot be polarised. The reason that only transverse wave can be polarised is that their vibrations can  be potentially occur in all directions perpendicular to the direction of travel.
  • Polarisation of "light wave" is possible only because they can oscillate in more than one orientation because they are transverse in Nature.
  • It has no dependence  on wavelength and frequencies
  • Hence option D is the right answer
Multiple choice physics measurements and experimentation vernier calliper and screw gauge least count of vernier calliper and screw gauge measurement of length

In a resonant column method, resonance occurs at two successive levels of $l _1=30.7 cm$ and $l _2=63.2 cm$ using a tuning fork of $f=512 Hz$. What is the maximum error in measuring speed of sound using the relations $v=f\lambda$ and $\lambda =2(l _2-l _1)$?

  1. 256 cm/sec

  2. 92 cm/sec

  3. 128 cm/sec

  4. 102.4 cm/sec
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The maximum error is given by :


$c=f\lambda = 512 \times 2(l _2-l _1)=512 \times 2 \times (63.2-30.7) = 332.8 \ m/s$

$\dfrac{\Delta c}{c} = \dfrac{\Delta {f}}{f}  + \dfrac{ {\Delta \lambda}}{\lambda}$

Least count of scale $=0.1 cm$ 

total error in measurement of $\lambda$ 

$\Rightarrow 2\times L.C. =0.2 cm$

Total error in measurement of $f$  $\Rightarrow 0$

$\dfrac{\Delta c}{332.8} = \dfrac{0}{f}  + \dfrac{ {0 .2}}{65}$

$\Delta c =  \dfrac{ {0.2}}{65}\times 332.8 =1.024 \ m/s =102.4 \ cm/s$

Multiple choice physics pressure pressure in fluids pressure in liquids introduction to pressure

A deep sea diver may hurt his ear drum during diving because of:

  1. lack of oxygen

  2. more atm pressure

  3. more water pressure

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

The pressure at a depth $h$ below the surface of water is given by 

$P=P _0+h\rho g$
Hence as the depth increases, the pressure increases.
Due to this increased pressure, as the diver goes deeper in sea water, the ear drum may get damaged.

Multiple choice

Which factor significantly influences the reverberation time of a room?

  1. The volume of the room

  2. The shape of the room

  3. The surface materials used in the room

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

The reverberation time of a room is influenced by a combination of factors, including the volume of the room, its shape, and the surface materials used. These factors determine how sound waves reflect, absorb, and dissipate within the space.

Multiple choice

Which parameter is used to quantify the loudness of a sound?

  1. Frequency

  2. Wavelength

  3. Amplitude

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

Loudness is typically quantified using the decibel (dB) scale, which is a logarithmic unit that expresses the ratio of a sound pressure level to a reference level.

Multiple choice

What is the phenomenon where sound waves bend around obstacles called?

  1. Diffraction

  2. Reflection

  3. Absorption

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

Diffraction is the bending of sound waves around obstacles or edges, causing them to spread out and travel beyond the obstacle's geometric shadow.