Q1. What is the primary requirement for sound to be produced?
a) An electric source
b) A vibrating object
c) A liquid medium
d) High temperature
Answer: b) A vibrating object
Explanation: Sound is produced when an object vibrates, creating a disturbance in the surrounding medium. This vibration leads to the generation of sound waves, as seen in the tuning fork experiment described in the chapter.
Q2. Which of the following media can sound not travel through?
a) Air
b) Water
c) Steel
d) Vacuum
Answer: d) Vacuum
Explanation: Sound requires a medium (solid, liquid, or gas) to travel through. In a vacuum, where there is no medium, sound waves cannot propagate, as demonstrated in the bell jar experiment in the chapter.
Q3. In a longitudinal wave, such as a sound wave, the particles of the medium:
a) Move perpendicular to the wave direction
b) Do not move at all
c) Move parallel to the wave direction
d) Move in a circular path
Answer: c) Move parallel to the wave direction
Explanation: In longitudinal waves, such as sound waves, the particles of the medium vibrate back and forth parallel to the direction of wave propagation. This movement creates compressions and rarefactions in the medium.
Q4. Which property of sound determines its pitch?
a) Amplitude
b) Speed
c) Wavelength
d) Frequency
Answer: d) Frequency
Explanation: The pitch of a sound is determined by its frequency. Higher frequencies correspond to higher pitches, while lower frequencies result in lower pitches. Pitch is how the human brain interprets the frequency of a sound.
Q5. Ultrasound is used in medical imaging. What makes it suitable for this purpose?
a) Its low frequency
b) Its ability to travel through vacuum
c) Its high frequency and non-invasiveness
d) Its visible nature
Answer: c) Its high frequency and non-invasiveness
Explanation: Ultrasound uses high-frequency sound waves, which are above the audible range for humans. These waves can penetrate various mediums, making them ideal for internal imaging in medicine without being invasive.
Q6. What phenomenon causes the ‘sonic boom’?
a) Reflection of sound
b) An object moving at subsonic speeds
c) An object traveling faster than the speed of sound
d) Interference of sound waves
Answer: c) An object traveling faster than the speed of sound
Explanation: A ‘sonic boom’ occurs when an object travels faster than the speed of sound. This leads to the accumulation of sound waves that release a large amount of energy as a loud, sharp sound, known as the sonic boom.
Q7. What is the term for the region of high pressure in a sound wave?
a) Rarefaction
b) Compression
c) Wavelength
d) Amplitude
Answer: b) Compression
Explanation: In a sound wave, the region where the particles of the medium are closer together, creating a high-pressure area, is known as a compression. This is contrasted with rarefaction, where particles are spread apart, creating a low-pressure area.
Q8. How does temperature affect the speed of sound in a given medium?
a) Speed increases with decreasing temperature
b) Speed is unaffected by temperature
c) Speed decreases with increasing temperature
d) Speed increases with increasing temperature
Answer: d) Speed increases with increasing temperature
Explanation: The speed of sound in a medium generally increases with an increase in temperature. As temperature rises, the particles of the medium move more vigorously, facilitating faster transmission of sound waves.
Q9. In the context of sound waves, what does the term ‘echo’ refer to?
a) The immediate sound heard from a source
b) A repeated reflection of sound
c) The absorption of sound by a medium
d) The change in the direction of sound waves
Answer: b) A repeated reflection of sound
Explanation: An echo is the sound heard after it gets reflected from a surface and reaches the listener with a delay, allowing the original and reflected sound to be distinguished as separate sounds.
Q10. Which characteristic of sound allows us to determine the quality or timbre of a musical note?
a) Loudness
b) Pitch
c) Frequency
d) Harmonics
Answer: d) Harmonics
Explanation: The quality or timbre of a sound is determined by the harmonics or overtones present in it. This characteristic helps us distinguish between different musical notes even if they have the same pitch and loudness.
Q11. What role does the pinna, a part of the human ear, play in hearing?
a) It amplifies sound waves
b) It collects and directs sound into the ear canal
c) It converts sound waves into electrical signals
d) It balances the pressure between the inner and outer ear
Answer: b) It collects and directs sound into the ear canal
Explanation: The pinna, or the outer part of the ear, functions to collect sound waves from the environment and direct them into the ear canal towards the eardrum.
Q12. In the SONAR technology, what is the purpose of using ultrasound waves?
a) To visualize the structure of the seabed
b) To measure the depth of the sea and locate underwater objects
c) To communicate with marine life
d) To generate electrical energy underwater
Answer: b) To measure the depth of the sea and locate underwater objects
Explanation: SONAR technology utilizes ultrasound waves to measure the distance, direction, and speed of underwater objects. This is achieved by sending out ultrasound waves and measuring the time taken for the echoes to return from objects like the seabed or other underwater features.
Q13. Which part of the human ear is directly involved in converting vibrations into electrical signals?
a) Pinna
b) Ear drum
c) Cochlea
d) Auditory canal
Answer: c) Cochlea
Explanation: The cochlea, located in the inner ear, is responsible for converting the vibrations in the ear caused by sound waves into electrical signals. These signals are then transmitted to the brain via the auditory nerve.
Q14. What is the main factor that determines the loudness of a sound?
a) Frequency of the sound wave
b) Temperature of the medium
c) Amplitude of the sound wave
d) Speed of the sound wave
Answer: c) Amplitude of the sound wave
Explanation: The loudness of a sound is primarily determined by its amplitude. Larger amplitudes result in louder sounds, while smaller amplitudes produce softer sounds.
Q15. What is the usual range of audible frequencies for the human ear?
a) 0 Hz to 20 Hz
b) 20 Hz to 20000 Hz
c) 20000 Hz to 200000 Hz
d) 1 Hz to 1000 Hz
Answer: b) 20 Hz to 20000 Hz
Explanation: The typical audible range for the average human ear extends from about 20 Hz to 20,000 Hz. Frequencies below and above this range are known as infrasound and ultrasound, respectively, and are not typically audible to humans.
Q16. In which medium would sound travel the fastest?
a) Air
b) Water
c) Steel
d) Vacuum
Answer: c) Steel
Explanation: Sound travels fastest in solids, with steel being a typical example where sound waves propagate more quickly compared to liquids (like water) and gases (like air). Sound cannot travel through a vacuum.
Q17. What is the phenomenon of reverberation in acoustics?
a) The absorption of sound by soft materials
b) The persistence of sound due to repeated reflections
c) The increase in frequency of sound in a closed space
d) The bending of sound waves due to temperature gradients
Answer: b) The persistence of sound due to repeated reflections
Explanation: Reverberation is the phenomenon where sound persists in a particular space as a result of repeated reflections from surfaces such as walls, ceilings, and floors. This can lead to a prolongation of sound even after the source has stopped emitting it.
Q18. Ultrasound is commonly used for which medical procedure?
a) Measuring blood pressure
b) Imaging internal organs
c) Hearing tests
d) Testing muscle flexibility
Answer: b) Imaging internal organs
Explanation: Ultrasound is widely used in medicine for imaging internal organs, a procedure known as ultrasonography. It allows for non-invasive visualization of internal body structures including muscles, tendons, blood vessels, joints, and internal organs.
Q19. What causes the rolling of thunder heard during a storm?
a) The high speed of sound in the atmosphere
b) The reflection of sound from multiple surfaces
c) The varying frequencies of sound produced by lightning
d) The interaction of sound with raindrops
Answer: b) The reflection of sound from multiple surfaces
Explanation: The rolling sound of thunder is due to the successive or multiple reflections of the sound from various surfaces like clouds and the Earth’s surface. These reflections cause variations in the time it takes for the sound to reach the listener, creating a prolonged rolling effect.
Q20. What type of waves are sound waves in air?
a) Transverse waves
b) Electromagnetic waves
c) Longitudinal waves
d) Gravitational waves
Answer: c) Longitudinal waves
Explanation: Sound waves in air are longitudinal waves. In these waves, the particles of the medium move parallel to the direction of wave propagation, creating alternating regions of compressions and rarefactions.
Q21. What is the purpose of using a curved ceiling in concert halls and auditoriums?
a) To enhance the aesthetic appeal of the hall
b) To improve lighting effects during performances
c) To reduce the intensity of sound
d) To ensure sound reaches all corners of the hall
Answer: d) To ensure sound reaches all corners of the hall
Explanation: Curved ceilings in concert halls and auditoriums are designed to facilitate the uniform spread of sound waves throughout the hall. The curvature helps in directing sound waves to different parts of the hall, ensuring that audience members can hear the performance clearly, regardless of their seating position.
Q22. What is the SI unit of frequency?
a) Meter (m)
b) Second (s)
c) Hertz (Hz)
d) Pascal (Pa)
Answer: c) Hertz (Hz)
Explanation: The SI unit of frequency is Hertz (Hz), which represents the number of cycles per second. In the context of sound, frequency is the number of sound vibrations or oscillations that occur per second.
Q23. Which of the following is not a use of ultrasound?
a) Navigating submarines using SONAR
b) Breaking kidney stones into smaller pieces
c) Cleaning delicate objects
d) Transmitting data through optical fibers
Answer: d) Transmitting data through optical fibers
Explanation: Ultrasound is used for various purposes like navigating submarines using SONAR, breaking kidney stones into smaller pieces (lithotripsy), and cleaning delicate objects. However, transmitting data through optical fibers is not a function of ultrasound; it is done using light, typically in the form of laser beams.
Q24. Why is it difficult to hear a distinct echo in a small room?
a) Because the sound gets absorbed by the walls
b) Due to insufficient distance for the sound to travel before reflection
c) Because of the low frequency of sound in small rooms
d) Due to interference of multiple sound waves
Answer: b) Due to insufficient distance for the sound to travel before reflection
Explanation: To hear a distinct echo, the sound waves need to travel to a reflective surface and back with enough time delay so that the echo doesn’t overlap with the original sound. In a small room, the distance is usually too short for this time delay to be sufficient, preventing the formation of a distinct echo.
Q25. What phenomenon demonstrates that sound cannot travel through a vacuum?
a) The Doppler Effect
b) The Bell Jar Experiment
c) The Resonance Experiment
d) The Double-slit Experiment
Answer: b) The Bell Jar Experiment
Explanation: The Bell Jar Experiment effectively demonstrates that sound cannot travel through a vacuum. In this experiment, a ringing bell is placed inside a jar from which air is gradually removed. As the air is evacuated, the sound becomes fainter and eventually inaudible, proving that sound requires a medium for its propagation.
Q26. Which of the following is a characteristic of infrasound?
a) Frequencies higher than 20,000 Hz
b) Frequencies that are audible to the human ear
c) Frequencies lower than 20 Hz
d) Frequencies used in ultrasound medical imaging
Answer: c) Frequencies lower than 20 Hz
Explanation: Infrasound refers to sound waves with frequencies below the audible range of the human ear, which is lower than 20 Hz. These low-frequency sounds are not detectable by humans but can be perceived by certain animals.
Q27. In a sound wave, the distance between two consecutive compressions or rarefactions is known as:
a) Amplitude
b) Frequency
c) Wavelength
d) Velocity
Answer: c) Wavelength
Explanation: The wavelength in a sound wave is the distance between two consecutive compressions or two consecutive rarefactions. It is a key property of a wave and is usually denoted by the Greek letter lambda (λ).
Q28. What is the purpose of a soundboard in an auditorium?
a) To absorb excessive sound and prevent echoes
b) To amplify the sound produced on stage
c) To reflect sound, ensuring it spreads evenly across the audience
d) To convert sound waves into electrical signals
Answer: c) To reflect sound, ensuring it spreads evenly across the audience
Explanation: A soundboard in an auditorium is used to reflect sound waves. It is strategically placed, often behind the stage, to ensure that the sound spreads evenly across the entire hall, providing a uniform auditory experience to the audience.
Q29. How do dolphins use ultrasound?
a) For communication with other dolphins
b) To detect food and navigate in water
c) For producing loud sounds to scare predators
d) To generate heat in cold waters
Answer: b) To detect food and navigate in water
Explanation: Dolphins use ultrasound for echolocation, which helps them navigate in water and locate food. They emit high-frequency sound waves, which bounce off objects in the water and return to them, providing information about the size, shape, and distance of objects.
Q30. Which part of the human ear vibrates in response to sound waves, initiating the process of hearing?
a) The cochlea
b) The eustachian tube
c) The auditory nerve
d) The tympanic membrane (eardrum)
Answer: d) The tympanic membrane (eardrum)
Explanation: The tympanic membrane, or eardrum, is a thin membrane that vibrates in response to sound waves. These vibrations are then transmitted to the bones in the middle ear, initiating the process of hearing.
Q31. What is the effect of altitude on the speed of sound in air?
a) Speed increases with higher altitude
b) Speed decreases with higher altitude
c) Speed remains constant regardless of altitude
d) Speed initially decreases, then increases at higher altitudes
Answer: b) Speed decreases with higher altitude
Explanation: The speed of sound in air generally decreases with higher altitude. This is primarily due to the decrease in temperature and air density at higher altitudes, which affects the speed at which sound waves travel.
Q32. What is the main factor that determines the pitch of a sound?
a) The amplitude of the sound wave
b) The speed of the sound wave
c) The frequency of the sound wave
d) The wavelength of the sound wave
Answer: c) The frequency of the sound wave
Explanation: The pitch of a sound is determined by its frequency. Higher frequencies are perceived as higher pitches, while lower frequencies are heard as lower pitches.
Q33. What type of sound waves are typically used in sonar technology?
a) Infrasonic waves
b) Ultrasonic waves
c) Radio waves
d) Visible light waves
Answer: b) Ultrasonic waves
Explanation: Sonar technology typically uses ultrasonic waves, which are high-frequency sound waves above the audible range of human hearing. These waves are ideal for navigating and detecting objects underwater.
Q34. How does sound absorption in an auditorium affect its acoustics?
a) It increases the echo effect
b) It decreases the clarity of sound
c) It reduces reverberation for better sound quality
d) It amplifies the sound produced on stage
Answer: c) It reduces reverberation for better sound quality
Explanation: Sound absorption in an auditorium reduces reverberation, thereby improving the overall sound quality. Materials that absorb sound are used to prevent excessive echoing and ensure that sound is clear and audible throughout the auditorium.
Q35. Which application utilizes ultrasound to break down kidney stones?
a) Echocardiography
b) Lithotripsy
c) Sonography
d) Doppler radar
Answer: b) Lithotripsy
Explanation: Lithotripsy is a medical procedure that utilizes ultrasound to break down kidney stones into smaller, passable pieces. It is a non-invasive technique that uses high-frequency sound waves to shatter the stones.
Q36. What is the term for the high-pitched sound produced by a fast-moving object surpassing the speed of sound?
a) Resonance
b) Doppler effect
c) Sonic boom
d) White noise
Answer: c) Sonic boom
Explanation: A sonic boom is the high-pitched, explosive sound produced when an object moves faster than the speed of sound. It occurs due to the sudden change in air pressure created by the object outrunning its own sound waves.
Q37. Which part of the human ear equalizes air pressure on either side of the eardrum?
a) Cochlea
b) Auditory canal
c) Eustachian tube
d) Semicircular canals
Answer: c) Eustachian tube
Explanation: The Eustachian tube connects the middle ear to the throat and plays a crucial role in equalizing air pressure on both sides of the eardrum. This equalization is important for the proper functioning of the eardrum.
Q38. What is the primary use of a megaphone?
a) To absorb sound and prevent echoes
b) To reduce the frequency of sound
c) To direct sound waves in a specific direction
d) To convert sound energy into electrical energy
Answer: c) To direct sound waves in a specific direction
Explanation: A megaphone, or loudhailer, is designed to focus and direct sound waves in a specific direction. Its conical shape helps in amplifying and directing the sound towards a particular area, making it louder and clearer for listeners in that direction.
Q39. What term describes the high-frequency sound waves produced by bats for echolocation?
a) Infrasound
b) Ultrasound
c) Radio waves
d) Microwaves
Answer: b) Ultrasound
Explanation: Bats produce high-frequency sound waves, known as ultrasound, for echolocation. These sound waves help them navigate and locate prey in the dark by reflecting off objects and returning to the bats, providing information about their environment.
Q40. How does the speed of sound in water compare to that in air?
a) It is faster in water than in air
b) It is slower in water than in air
c) It is the same in both water and air
d) It varies unpredictably between water and air
Answer: a) It is faster in water than in air
Explanation: The speed of sound is generally faster in water than in air. This is because water is a denser medium than air, allowing sound waves to travel more quickly through it.
Q41. What is the cause of the Doppler Effect in sound?
a) The reflection of sound from different surfaces
b) The interference of sound waves with different frequencies
c) The relative motion between the source of sound and the observer
d) The change in amplitude of the sound wave
Answer: c) The relative motion between the source of sound and the observer
Explanation: The Doppler Effect in sound is caused by the relative motion between the source of the sound and the observer. When the source of sound approaches the observer, the sound waves are compressed, resulting in a higher pitch. Conversely, as the source moves away, the waves are stretched, leading to a lower pitch.
Q42. In the context of sound waves, what is resonance?
a) The increase in amplitude when the frequency of a force matches the natural frequency of a system
b) The reflection of sound waves from a surface
c) The absorption of sound by a medium
d) The interference of two sound waves of different frequencies
Answer: a) The increase in amplitude when the frequency of a force matches the natural frequency of a system
Explanation: Resonance in sound occurs when the frequency of an externally applied force matches the natural frequency of a system, leading to a significant increase in the amplitude of the system’s oscillations. This phenomenon is often observed in musical instruments.
Q43. What is the role of the hammer, anvil, and stirrup in the human ear?
a) To convert sound waves into electrical signals
b) To protect the inner ear from loud sounds
c) To amplify the vibrations received from the eardrum
d) To equalize pressure in the ear canal
Answer: c) To amplify the vibrations received from the eardrum
Explanation: The hammer, anvil, and stirrup (also known as the malleus, incus, and stapes) are tiny bones in the middle ear. They function together to amplify the vibrations received from the eardrum and transmit them to the fluid in the cochlea of the inner ear.
Q44. What is the typical speed of sound in air at 22 ºC?
a) Approximately 331 m/s
b) Approximately 344 m/s
c) Approximately 299,792 km/s
d) Approximately 1,500 m/s
Answer: b) Approximately 344 m/s
Explanation: The speed of sound in air at 22 ºC is approximately 344 meters per second. This speed can vary slightly depending on factors such as humidity and air pressure.
Q45. Which factor does not affect the speed of sound in a medium?
a) Temperature of the medium
b) Pressure of the medium
c) Humidity of the medium
d) Color of the medium
Answer: d) Color of the medium
Explanation: The speed of sound in a medium is affected by factors like temperature, pressure, and humidity, but not by the color of the medium. The color is irrelevant to the physical properties that influence the propagation of sound waves.
Q46. What is the main advantage of using ultrasonography in medical diagnostics?
a) It allows for the transmission of data through optical fibers
b) It is an invasive technique for internal examination
c) It provides a non-invasive way of imaging internal organs
d) It uses high-intensity radiation for clear images
Answer: c) It provides a non-invasive way of imaging internal organs
Explanation: Ultrasonography is a significant medical diagnostic tool because it provides a non-invasive way to image internal organs. It uses high-frequency sound waves to create images of structures within the body, making it a safe and painless procedure.
Q47. What is the main reason for using sound-absorbing materials in the construction of auditoriums?
a) To enhance the visual appeal of the auditorium
b) To amplify sounds on the stage
c) To prevent the loss of sound energy to the outside environment
d) To reduce reverberation and improve sound clarity
Answer: d) To reduce reverberation and improve sound clarity
Explanation: Sound-absorbing materials are used in auditoriums to reduce reverberation, which is the persistence of sound in a space due to repeated reflections. By absorbing sound, these materials improve sound clarity and prevent the muddling of audio, enhancing the audience’s listening experience.
Q48. In the context of sound waves, what is amplitude?
a) The height of the wave from the rest position to the crest
b) The distance covered by one complete wave cycle
c) The number of waves produced per second
d) The velocity of the wave as it travels through a medium
Answer: a) The height of the wave from the rest position to the crest
Explanation: The amplitude of a sound wave is the height of the wave from its rest position to the crest (or to the trough). It represents the maximum displacement of the particles of the medium from their equilibrium position and is related to the loudness of the sound.
Q49. What type of sound waves are used by a stethoscope to detect internal body sounds?
a) Ultrasonic waves
b) Infrasonic waves
c) Audible sound waves
d) Electromagnetic waves
Answer: c) Audible sound waves
Explanation: A stethoscope uses audible sound waves to detect internal body sounds, such as heartbeats and lung sounds. It amplifies these sounds, allowing healthcare professionals to assess the functioning of various internal organs.
Q50. How does the frequency of a sound wave affect its wavelength in a given medium?
a) Higher frequency results in a longer wavelength
b) Higher frequency results in a shorter wavelength
c) Frequency has no effect on the wavelength
d) Frequency inversely affects the speed of sound, not the wavelength
Answer: b) Higher frequency results in a shorter wavelength
Explanation: In a given medium, the wavelength of a sound wave is inversely proportional to its frequency. This means that higher frequency sound waves have shorter wavelengths, and lower frequency sound waves have longer wavelengths.
Q51. What is the primary purpose of the outer ear, or pinna?
a) To convert sound waves into electrical signals
b) To amplify sound waves
c) To collect and direct sound into the ear canal
d) To balance air pressure in the ear
Answer: c) To collect and direct sound into the ear canal
Explanation: The primary purpose of the pinna, or the outer part of the ear, is to collect sound waves from the environment and funnel them into the ear canal towards the eardrum.
Q52. Why are infrasonic frequencies not audible to humans?
a) They are too high-pitched for the human ear to detect
b) They are absorbed by the atmosphere
c) They are too low-pitched for the human ear to detect
d) They are only produced in water
Answer: c) They are too low-pitched for the human ear to detect
Explanation: Infrasonic frequencies are below the audible range of the human ear, typically below 20 Hz. These frequencies are too low-pitched for humans to hear, although some animals can perceive them.
Q53. What is the primary factor that distinguishes music from noise?
a) The loudness of the sound
b) The pitch of the sound
c) The harmony and rhythm in the sound
d) The frequency of the sound waves
Answer: c) The harmony and rhythm in the sound
Explanation: The primary factor that distinguishes music from noise is the presence of harmony and rhythm. Music typically has a structured arrangement of sounds, with a pleasing and harmonious combination of notes, whereas noise lacks these qualities and is often perceived as unpleasant.
Q54. What is the role of the auditory nerve in hearing?
a) To vibrate in response to sound waves
b) To amplify sound waves
c) To transmit electrical signals from the cochlea to the brain
d) To equalize pressure in the ear
Answer: c) To transmit electrical signals from the cochlea to the brain
Explanation: The auditory nerve plays a crucial role in hearing by transmitting electrical signals from the cochlea in the inner ear to the brain. These electrical signals represent the sound information that the brain interprets, allowing us to perceive and understand sounds.