Sound Wave MCQ Quiz - Objective Question with Answer for Sound Wave - Download Free PDF

Concept:

• A sound is a form of energy that produces the sensation of hearing in our ears.
• Sound is a type of longitudinal wave.
• Sound is measured in Decibels(Db).
• The speed of the sound varies in different mediums.

Explanation:

• Sound from a violin and a flute played at the same time travel at the same speed.
  • Both the sounds travel through the same medium which is air.
  • Both the sound travel through at the same speed at the same time but the sound we receive are different due to characteristics associated with the sound such as pitch and amplitude.
  • Hence, option 1 is correct.
• Two sound waves of the same intensity would not be perceived to have the same loudness because of the human's ear tendency to amplify sounds having frequencies in the range from 10kHz to 50kHz, sounds with these intensities seem louder to the human ear. Hence, option 2 is incorrect.
• Speed of sound in hot air is more than that of the room temperature because heat makes air molecules move around faster. Hence, option 3 is correct.
• The speed of sound depends on the density of the material.
  • Tightly packed material molecules transfer the sound at high speed.
  • Speed of sound is fastest in Solids, Liquids then Gas.
  • Hence, option 4 is correct.

Thus, the incorrect statement is that two sound waves of the same intensity will always have equal loudness. 

Important Points Amplitude:

• Amplitude is the measure of compression or rarefaction of particles of a medium through which sound is traveling.
• The higher the amplitude, the louder the sound.
• The amplitude A is related to loudness as loudness ∝ A2

Frequency:

• Frequency refers to the rate of vibration of sound.
• The pitch of a sound is decided by the measure of frequency.
• The higher the frequency, the shriller the sound.
• Frequency measured in Hertz (Hz).

Additional Information Sound in the air: 

• In a gas-like air, the particles are generally far apart so they travel further before they bump into one another.
• There is not much resistance to movement so it doesn’t take much to start a wave, but it won’t travel as fast.

Sound in water:

•  In water, the particles are much closer together, and they can quickly transmit vibrational energy from one particle to the next.
• This means that the sound wave travels over four times faster than it would in the air, but it takes a lot of energy to start the vibration.

Sound in solids: 

• In a solid, the particles are even closer together and linked by chemical bonds so the wave travels even faster than it does in either liquid or air, but you need quite a lot of energy to start the wave at the beginning.

Concept:

• Sound: A sound is a form of energy that produces the sensation of hearing in our ears.

Amplitude:

• Amplitude is the measure of compression or rarefaction of particles of a medium through which sound is traveling.
• The higher the amplitude, the louder the sound.
• The amplitude A is related to loudness as loudness ∝ A2

Frequency:

• Frequency refers to the rate of vibration of sound.
• The pitch of a sound is decided by the measure of frequency.
• The higher the frequency, the shriller the sound.
• Frequency measured in Hertz (Hz).

Explanation:

• The loudness and softness of a sound wave is the sensation that depends upon its amplitude.
•  Since the loudness depends on amplitude. So, to change a feeble sound to a loud sound students should increase the amplitude of the sound because the large amplitude produces a loud sound whereas the small amplitude produces a feeble sound.

Therefore, the correct answer is the amplitude of the sound.

The correct answer is Statement I and III are correct.

Key Points

• Statement I: The frequency of vibration determines the pitch of the sound. This statement is correct as the pitch is directly related to the frequency of the sound wave; higher frequency results in higher pitch.
• Statement II: A higher frequency of vibration produces a lower pitch. This statement is incorrect as higher frequency corresponds to a higher pitch.
• Statement III: Amplitude affects the loudness of the sound. This statement is correct as the loudness of a sound is determined by its amplitude; higher amplitude results in louder sound.

Additional Information

• Pitch: The perceived frequency of a sound; it is how high or low a sound seems to a listener.
• Frequency: The number of vibrations or cycles per second of a sound wave, measured in Hertz (Hz).
• Amplitude: The height of the sound wave, which determines the loudness or volume of the sound.
• Loudness: A subjective perception of sound pressure, influenced by the amplitude of the sound wave.
• Sound waves are characterized by their wavelength, frequency, amplitude, and speed, which together determine the sound's pitch, loudness, and quality.

The correct answer is by the take off of a jet plane.

Key Points

• The take off of a jet plane generates an extremely high level of sound.
• Jet engines produce noise levels that can exceed 140 decibels at close range, which is significantly higher than many other sources of noise.
• At these levels, sound can cause immediate hearing damage if proper protection is not used.
• The noise generated is a combination of engine noise and aerodynamic noise, which occurs due to the high-speed movement of air around the aircraft.
• Airports implement various noise abatement procedures to minimize the impact of jet noise on surrounding communities.

 Additional Information

• Vehicular emissions
  • Vehicular emissions primarily refer to the release of pollutants from vehicles, such as carbon monoxide, hydrocarbons, and nitrogen oxides, rather than noise.
  • However, vehicles do contribute to urban noise pollution, especially in areas with heavy traffic.
• House chimneys
  • House chimneys are sources of smoke and sometimes pollutants but do not generate significant noise.
  • The primary concern with chimneys is the emission of particulate matter and other pollutants.
• Industrial smoke
  • Industrial smoke is associated with the release of pollutants, including particulate matter and chemicals, into the air.
  • While some industrial processes can be noisy, the term "industrial smoke" specifically refers to air pollution, not noise.

The Correct answer is reverberation.

Key Points

• Reverberation is the phenomenon of multiple echoes due to repeated reflections.
• It occurs when sound waves reflect off surfaces such as walls, ceilings, and floors.
• This is commonly experienced in large, enclosed spaces like auditoriums, halls, and churches.
• Reverberation can enhance the quality of sound, making it fuller and richer.
• However, excessive reverberation can cause sound to become muddled and unclear.
• Architects and engineers often design spaces with materials that control reverberation to optimize sound quality.
• Measurement of reverberation time is crucial in acoustical engineering to ensure the desired sound characteristics of a space.

 Additional Information

• Resonance
  • Resonance is the phenomenon where an object or system vibrates at an increased amplitude at specific frequencies.
  • This occurs when the frequency of external vibrations matches an object's natural frequency.
  • Resonance is important in various applications, including musical instruments and engineering designs.
• Refraction
  • Refraction is the bending of light or sound waves when they pass from one medium to another.
  • This change in direction is due to a change in the speed of waves in different media.
  • Refraction is commonly observed in phenomena like the bending of light in water.
• Diffraction
  • Diffraction is the bending and spreading of waves around obstacles and through openings.
  • It is most noticeable when the wavelength is comparable to the size of the obstacle or opening.
  • Diffraction is important in applications such as sound wave propagation and the design of optical instruments.

The correct answer is 850 m.

Key Points

• Echo: If we shout or clap near a suitable reflecting object such as a tall building or a mountain, we will hear the same sound again a little later. This sound which we hear is called an echo.
• Echoes are heard due to the phenomenon of Reflection of sound waves.
• To hear the echo clearly, the reflecting object must be more than 17.2 m from the sound source for the echo to be heard by a person standing at the source.

Additional Information

Given,

Time taken to heard first echo (t₁) = 2 sec

Time taken to heard second echo (t₂) = 3 sec

Velocity of sound (v) = 340 m/s

Let d be the distance between two cliffs, x is the distance between the man and cliff 2, and (d - x) is the distance between the man and cliff 1.

The speed of sound is

\(Speed\;of\;Sound\;\left( v \right) = \frac{{Distance\;\left( d \right)}}{{Time\;\left( t \right)}}\)

The distance between the man and cliff 2 is 

⇒ 2x = v × t₁

\( \Rightarrow x = \frac{{v\; \times\; {t_1}}}{2}\)

\(\Rightarrow x = \frac{{340\; \times \;2}}{2} = 340\;m\)

The distance between the man and cliff 1 is 

⇒ 2(d - x) = v × t₂

\( \Rightarrow \left( {d - x} \right) = \frac{{v\; \times \;{t_2}}}{2}\)

\( \Rightarrow \left( {d - 340} \right) = \frac{{340\; \times \;3}}{2} = 510\)

⇒ d = (510 + 340) m = 850 m

Hence the correct option is 850 m.

The correct answer is remains same.

Concept:
Sound

• Sound is a form of energy which produces a sensation of hearing in our ears.
• Sound is produced by vibrating objects. The matter or substance through which sound is transmitted is called a medium. It can be solid, liquid or gas. 

Explanation:

• As the loudness of the mobile ringtone increases, the frequency of the ringtone remains same.
• The loudness is expressed in a unit called decibel (dB). 
• Loudness is the physical response of the ear to the intensity of sound.
• A sound with more energy is referred to as a strong sound.
• Loudness of sound is proportional to the square of the amplitude of the vibration producing the sound. 
• Loudness ∝ (amplitude)²
• The loudness of sound waves does not depend on the frequency of the sound waves. 
• Loudness and Amplitude: Loudness is the perception of how intense or strong a sound seems to our ears. It is directly related to the amplitude of a sound wave.
  • Increasing the amplitude increases the loudness, while decreasing the amplitude decreases the loudness.
• Frequency and Pitch: Frequency is the number of oscillations (cycles) that a sound wave completes in one second, measured in Hertz (Hz).
  • Pitch is the perceptual attribute of the sound that allows us to classify it as higher or lower; it is directly related to the frequency of the sound wave.
  • Higher frequency corresponds to a higher pitch, and lower frequency corresponds to a lower pitch.
• Intensity and Energy: Intensity is the amount of energy a sound wave carries per unit area per unit time, and it is proportional to the square of the amplitude.

Higher intensity results in louder sounds but does not affect the frequency.

Mistake Points

•  Loudness is related to amplitude.
• Pitch is related to frequency.
• Intensity is associated with energy of the sound wave and is proportional to amplitude squared.

Additional Information

• When the amplitude is greater, the loudness of the sound is also higher. 
• When the amplitude is low, the sound produced will be dim.

The correct answer is Amplitude.

• Loudness means how loud or soft a sound seems to a listener.

Key Points 

• Loudness is related to amplitude and intensity is one of the most salient qualities of a sound which is a measure of the amount of energy in sound waves.
• The unit of intensity is the decibel (dB).

Additional Information

• Speed- The speed of sound is the distance traveled per unit of time by a sound wave when it propagates through an elastic medium.
• Wavelength- The wavelength of a sound is the distance between adjacent identical parts of a wave.
• Frequency- The number of vibrations counted per second is called frequency. The unit of frequency is called hertz (Hz).

The correct answer is 0.04m.

Solution:

Velocity= Frequency* wavelength

Velocity=352m/s

Frequency= 8800Hz

therefore wavelength=velocity/frequency

352/8800=0.04m

hence wavelenght is 0.04 m

The correct answer is Loud sound.

Key Points

• Sound travels as a longitudinal wave.
• A sound wave traveling through air is indeed a longitudinal wave with compressions and rarefactions.
• The study of sound is called acoustics.
• The large amplitude of sound vibrations will produce a loud sound.
  • The intensity of sound is identified by loudness.
  • The loudness of sound is proportional to the square of the amplitude of the vibration producing the sound.
    • If the amplitude of vibration is large, the sound produced is loud.
    • If the amplitude is small, the sound produced is feeble.
  • The loudness of sound depends on the amplitude of vibration of sound-producing objects.
• Sound is a mechanical wave and needs a material medium like air, water, steel.
• The speed of sound depends on the properties of the medium through which it travels.
• Sound cannot travel in a vacuum.
• Sound travels faster in solids.
• The audible range of an average human is 20 Hz — 20 kHz.
• Speed of sound in air = 343 m/s.
• Hertz(Hz) is the unit of the frequency of sound.
• Decibels(dB) is the unit of Intensity of sound.

The correct answer is 600 m.

Here given:

• frequency = 50 Hz,
• wavelength = 4 m.

So, the velocity of wave = Frequency × Wavelength

= 50 × 4

= 200 m/s.
So the distance travelled by the sound wave in 3 s is:

 200 × 3

= 600 m.

The correct answer is Solids.Key Points

• Concept:
  • The speed of the sound depends on the density of the medium through which it is travelling.
  • The particles in the solid medium are closely packed. Hence, the density is high. Information from one molecule to another molecule travels faster in the solid medium.
  • In liquid, the molecules are farther apart than in solids. Hence, the density is low for liquids.
  • In gas, the molecules are very loosely dispersed. The speed of the sound wave will be maximum in steel. 
• Explanation:
  • Sound is a mechanical wave that needs a medium to travel.
  • The speed of sound is maximum in solid, then it is in liquid and it is the slowest in gases.
  • The speed of sound remains almost the same for all frequencies in a given medium under the same physical conditions.
• Notes:
  • The velocity of sound waves in air is 330 m/s. 
  • The velocity of sound waves in steel is 5920 m/s. 
  • The velocity of sound waves in a vacuum is zero. 
  • The velocity of sound waves in water is 1480 m/s. 

The correct answer is WaveLength.

About WaveLength:

• Wavelength is defined as the distance between the Identical points (Crests) in the cycles of a waveform signal which propagated in space or along a wire. In Wireless Systems, this length is usually measured in Centimeters (cm), Millimeters (mm), and Meters (m). It is denoted by the Greek letter Lambda (λ). 
• In a simple manner, if we defined the Wavelength so, the distance between two successive Crest and Trough of a wave. Wavelength is always measured in the direction of the wave. The formula of the Wavelength is represented by (λ =V/F).
• It is traveled from one(1) Crest wave to another wave and from one(1) Trough wave to another of a wave,( Electromagnetic wave, Sound wave, or any other Wave). The Crest is known as the (Highest point) of the wave and the Trough is known as the (Lowest point) of the wave.
• The wavelength of light varies with Colors, every color has a different wavelength. Like Red color has the (longest wavelength) and Violet has the (least wavelength). 
• Wavelength is inversely proportional to Frequency. This means the (Longer) the wavelength, the (Shorter) the Frequency. In another way, (Shorter) the wavelength, (Higher) will be the Frequency.

Image of the Wavelength:

Notes:

• The Amplitude is defined as the maximum extent of an Oscillation or Vibration or oscillation, measured from the position of Equilibrium. It is denoted as (A). Its SI unit is the meter (m).
• Frequency is defined as the rate at which something occurs over a particular (period of time). It is denoted as (F) and the unit is Hertz.
• Wave Number is defined as the number of Waves in a unit distance travels by the sound wave. Its unit is measured in meters (1/m).

The correct answer is only longitudinal.

Concept:

• Sound wave: The longitudinal wave in an elastic medium that produces an audible sensation is called a sound wave.
  • As sound waves are longitudinal waves, the air particles vibrate to and fro in the direction of propagation of sound.
  • It is a wave of compression and rarefaction.
  • Compressions and rarefactions are part of a sound wave.

• Compression: A region in a longitudinal wave where the particles are closest together is called compression. Compression has high density and high pressure

  Rarefaction: A region in a longitudinal wave where the particles are furthest apart is called rarefaction. The rarefaction has a low density and low pressure

Key Points

• Longitudinal waves- The particles displaced in this type of waves are parallel to the direction the wave travels.
  • Sound waves are longitudinal waves. 
  • The sound waves are longitudinal waves because particles of the medium through which the sound travels vibrate parallel to the direction that the sound wave moves.

Additional Information

• Transverse wave - The particles displaced in this type of waves are perpendicular to the direction the wave travels.
  • In light waves, the oscillations of the electric and magnetic fields are transverse.

The correct answer is Ultra sonic waves

Key Points

•  Ultrasonic waves are used in the dishwasher or to wash the machines.
• Objects to be cleaned are placed in a cleaning solution and ultrasonic waves are sent into the solution.
• The particles of dust, grease, and dirt get detached and drop out due to the high frequency waves.
• The objects thus get thoroughly cleaned.

Additional Information

Other important uses of Ultrasonic waves are :

• Used to detect cracks and flaws in metal blocks.
• Used for getting images of internal organs of the human body.
• Used to measure the distance, direction and speed of underwater objects.
• Bats search out prey and fly in the dark night by emitting and detecting reflections of ultrasonic waves.