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 general knowledge history

Decibel used to measure?

  1. light intensity

  2. sound intensity

  3. Current

  4. Magnetic Flux
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The decibel (dB) scale measures sound intensity on a logarithmic scale, comparing a given sound pressure level to a reference value. It is used to quantify the loudness of sounds, with 0 dB representing the threshold of human hearing and normal conversation around 60 dB. The logarithmic nature means every 10 dB increase represents a tenfold increase in sound intensity.

Multiple choice general knowledge

Guess the name of the low-pitched sound heard in numerous places worldwide, especially in the USA, UK, and northern europe.This sounds similar to the distant sound of diesel engine but is undetectable by microphones or VLF antennae.

  1. Tao's Hum

  2. Chao's Hum

  3. Hallabello of hell

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

The Hum is an unexplained low-frequency phenomenon reported in various locations worldwide. The Taos Hum (New Mexico, USA) is the most famous case, first widely reported in the early 1990s. Similar hums have been documented in the UK (Bristol Hum) and other places. The phenomenon is known as 'The Hum' or by location names (Taos Hum, Bristol Hum), not 'Tao's Hum'.

Multiple choice general knowledge science & technology

Why does your voice sound different to you on a recording?

  1. When you hear yourself speak regularly, the sound waves emanate through the tissue, bone, and other material, which changes its sound.

  2. When you hear yourself speak regularly, the sound waves bounce off who you are talking to, which changes its sound.

  3. The speakers of the cassette recorder distort the sound of your recorded voice.

  4. I don't know
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When you speak, you hear your voice through two pathways: air conduction (sound waves through air) and bone conduction (vibrations through skull bones). Bone conduction enhances lower frequencies, making your voice sound fuller to yourself. A recording only captures the air-conducted sound, which lacks this bass boost and thus sounds thinner and higher-pitched.

Multiple choice general knowledge science & technology

You are sitting in a baseball game in bleachers far from the field. You see the batter hit the ball and then you hear the crack of the bat. Why the delay?

  1. The sound has to travel through a lot of material (all the people in the stadium) before it reaches your ear.

  2. Light travels almost one million times faster than sound.

  3. Your brain anticipates what is going to happen visually, so you see the act a split second before it actually happens.

  4. You are too far away to hear the actual sound of the bat hitting the ball. What you hear is the echo of the actual sound.

  5. I don't know
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Light travels at approximately 300,000 kilometers per second, while sound travels at only 343 meters per second in air. This means light is nearly one million times faster than sound. When you're far from the action, the light arrives almost instantly, but the sound takes noticeable time to travel the same distance.

Multiple choice general knowledge

There was ____ sound in ____ living room.

  1. the - Ø

  2. the - the

  3. Ø - Ø

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

We use "a" before "sound" because it's the first mention of an indefinite sound. We use "the" before "living room" because it refers to a specific, known room in the context - typically understood to be the speaker's or a relevant house's living room.

Multiple choice general knowledge science & technology

What is the speed of sound in air in meters per second (at a pressure of one atmosphere and temperature of 25oC)?

  1. 110

  2. 230

  3. 490

  4. 330
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The speed of sound in air at 25°C is approximately 346 m/s. Among the options, 330 m/s is the closest approximation. The speed of sound in air increases with temperature and is roughly 331 m/s at 0°C, increasing by about 0.6 m/s per degree Celsius.

Multiple choice general knowledge science & technology

Decibel is the unit for

  1. speed of light

  2. radio wave frequency

  3. intensity of sound

  4. intensity of heat
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The decibel (dB) measures the intensity or loudness of sound. Speed of light is measured in m/s. Radio wave frequency is measured in Hertz. Heat intensity can be measured in temperature units or calories/watts, not decibels. Decibels can also measure other logarithmic ratios (like signal power), but sound intensity is the most common educational context.

Multiple choice general knowledge science & technology

Fathom is the unit of

  1. sound

  2. depth

  3. frequency

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

A fathom is a unit of depth measurement used primarily in nautical contexts to measure water depth (1 fathom = 6 feet). While it technically measures distance, in educational contexts it's specifically associated with depth. Sound uses decibels. Frequency uses Hertz. General distance uses meters or feet.

Multiple choice general knowledge science & technology

Sound waves in air are

  1. transverse

  2. longitudinal

  3. electromagnetic

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

Sound waves in air are longitudinal waves - the particles oscillate parallel to the direction of wave propagation (compression and rarefaction). Only transverse waves can be polarized. Sound is NOT electromagnetic.

Multiple choice softskills communication

There are parts of the Cordilleras were you can hear loud ________of your voice if you shout loud enough.

  1. echos

  2. echoes

  3. echos'

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

Echo is a noun that ends in -o, and like other similar words (potato, tomato, hero, torpedo), it forms its plural by adding -es to become echoes. This pattern follows standard English rules for words ending in consonant + o. Echos would be incorrect because it doesn't follow the -es rule, echos' is possessive (not plural), and echoses is not a valid English word form.