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Q1. Sound can travel through
Sound is a mechanical wave that requires a material medium to travel. It can travel through solids, liquids, and gases. Sound travels fastest in solids because particles are closely packed, slower in liquids, and slowest in gases because particles are far apart. Sound cannot travel through vacuum because there are no particles to vibrate and carry the wave.
Q2. Which motion is essential for sound production?
Vibratory motion (to and fro motion about a mean position) is essential for sound production. When an object vibrates, it creates disturbances in the surrounding medium, which travel as sound waves. Linear, uniform, and circular motions do not produce sound unless they involve vibration.
Q3. Sound reaches our ears due to the
Sound reaches our ears due to the movement of disturbance (energy) through the medium. The particles of the medium do not travel from the source to our ears; they only vibrate about their mean positions and pass the disturbance forward. The disturbance (wave) travels, not the medium itself.
Q4. A wave is defined as
A wave is defined as a disturbance that travels through a medium, transferring energy from one point to another without the net movement of the medium itself. In sound waves, the disturbance is the vibration of particles that propagates through the medium.
Q5. Compression is a region of
Compression is a region in a longitudinal wave where particles are crowded together, creating a region of high pressure and high density. This happens when the vibrating object moves forward, pushing the particles closer together.
Q6. Which of the following proves that sound needs vibration?
A vibrating tuning fork produces sound because its prongs vibrate. When you touch a vibrating tuning fork, you can feel the vibrations, and you hear the sound. This experiment proves that sound is produced by vibration. A burning candle, flow of water, and reflection of light do not involve vibration producing sound.
Q7. Which of the following vibrates to produce sound in a guitar?
In a guitar, the strings vibrate to produce sound. When the strings are plucked, they vibrate and set the air around them into motion, producing sound waves. The body of the guitar acts as a resonator to amplify the sound, but the strings are the primary vibrating parts.
Q8. When a vibrating object moves forward, it creates
When a vibrating object moves forward, it pushes the particles in front of it, creating a region of high pressure called compression. When the object moves backward, it creates a region of low pressure called rarefaction. These alternating compressions and rarefactions form a sound wave.
Q9. Which part vibrates in a drum to produce sound?
In a drum, the stretched membrane (skin) vibrates when struck. This vibration creates sound waves in the surrounding air. The drumstick is used to strike the membrane, and the stand holds the drum, but the membrane is the vibrating part that produces sound.
Q10. Sound propagation can be visualised as the propagation of
Sound propagation can be visualised as the propagation of pressure variations through a medium. Sound waves consist of alternating regions of high pressure (compressions) and low pressure (rarefactions) that travel through the medium. Temperature, light, and heat are not the primary carriers of sound.
Q11. In the tin-can experiment, the light spot dances due to
In the tin-can experiment, a balloon is stretched over the open end of a can, and a mirror is attached to it. When sound is produced near the can, the balloon vibrates, causing the mirror to move and the light spot to dance. This shows that sound causes vibrations in a material.
Q12. In sound propagation, the particles of the medium
In sound propagation, the particles of the medium vibrate about their mean positions. They do not move permanently forward or travel long distances. They transfer energy to neighbouring particles through their vibrations, allowing the disturbance (wave) to travel forward.
Q13. In a rarefaction, the density of particles is
In a rarefaction, the density of particles is minimum because particles are spread apart. Rarefaction is a region of low pressure and low density, created when the vibrating object moves backward, pulling particles away from each other.
Q14. A bird’s buzzing sound is produced due to
A bird’s buzzing sound is produced due to the vibration of its wings. As the wings flap rapidly, they create vibrations in the air, producing sound. This is similar to how a bee or mosquito produces sound by beating its wings at a high frequency.
Q15. When sound reaches our ear, it causes
When sound reaches our ear, it causes the eardrum (tympanic membrane) to vibrate. These vibrations are then transmitted through the middle ear bones to the inner ear, where they are converted into electrical signals for the brain to interpret. The eardrum is the first part of the ear that responds to sound waves.
Q16. Which type of motion is vibration?
Vibration is a rapid to and fro motion about a mean position. It is also called oscillatory motion. Circular motion is movement along a circle, rotational motion is spinning around an axis, and uniform motion is movement at constant speed in a straight line. Vibration is the to and fro movement essential for sound production.
Q17. A stretched rubber band produces sound when
A stretched rubber band produces sound when it is plucked and vibrated. The vibration of the rubber band sets the surrounding air particles into motion, creating sound waves. Heating, painting, or pressing it without vibration does not produce sound.
Q18. In a compression, the density of particles is
In a compression, the density of particles is maximum because particles are crowded together. This region has high pressure and high density. Compressions are formed when the vibrating object moves forward, pushing the particles closer together.
Q19. Sound produced by scratching is due to
Sound produced by scratching is due to vibrations. When you scratch a surface, the irregularities on the surface cause rapid vibrations that produce sound. While friction is involved, the actual production of sound is due to the resulting vibrations.
Q20. Which of the following cannot produce sound?
A non-vibrating stone cannot produce sound because sound is produced only by vibrations. A vibrating membrane, vibrating string, and vibrating ruler all produce sound because they are in motion. A stone at rest has no vibrations, so it cannot produce sound.
Q21. Which activity shows sound causing vibration?
The dancing light spot experiment (tin-can experiment) shows sound causing vibration. When sound is produced near the can, the balloon vibrates, making the light spot dance. This demonstrates that sound waves can cause vibrations in objects. Falling stone, burning paper, and flowing water do not demonstrate this.
Q22. Sound cannot travel through
Sound cannot travel through a vacuum because there are no particles to vibrate and carry the sound wave. Sound requires a material medium (solid, liquid, or gas) to travel. Water, air, and steel are all media through which sound can travel.
Q23. Sound waves are longitudinal because
Sound waves are longitudinal because the particles of the medium vibrate parallel to the direction of wave propagation. In a longitudinal wave, compressions and rarefactions are formed along the direction of wave travel. Transverse waves have particles vibrating perpendicular to the wave direction.
Q24. Sound cannot be produced without
Sound cannot be produced without vibrations. Vibrations are essential for sound production. While sound also needs a medium to travel, vibrations are the source of sound. Even in the absence of a medium (vacuum), sound cannot be produced unless there is a vibrating source, though it cannot travel to our ears.
Q25. The most common medium for sound is
Air is the most common medium for sound because we live in air and most sounds we hear travel through air. Sound travels through air to reach our ears. Glass, steel, and water are also media, but air is the most common medium for everyday sound.
Q26. Sound is produced due to
Sound is produced due to vibrations. When an object vibrates, it creates disturbances in the surrounding medium, producing sound waves. Heat, light, and pressure can be associated with other phenomena, but sound specifically requires vibrations.
Q27. The first particle disturbed by a vibrating object
The first particle disturbed by a vibrating object pushes its neighbouring particles, transferring energy to them. This creates a chain reaction where each particle passes the disturbance to the next. The particles do not move permanently or stop vibrating; they vibrate about their mean positions.
Q28. Without a medium, sound
Without a medium, sound cannot travel. Sound waves are mechanical waves that require a material medium to propagate. In a vacuum, there are no particles to vibrate, so sound cannot travel. This is why sound cannot be heard in space.
Q29. Sound waves consist of alternating
Sound waves consist of alternating compressions (regions of high pressure) and rarefactions (regions of low pressure). These regions are formed due to the vibrations of particles in the medium. Peaks and troughs are characteristics of transverse waves, not sound waves.
Q30. Sound travels in the form of
Sound travels in the form of mechanical waves because they require a material medium for propagation. Mechanical waves transfer energy through the vibration of particles. Light and heat waves are electromagnetic, and they do not require a medium.
Q31. Compression and rarefaction occur due to
Compression and rarefaction occur due to density variation. In a compression, particles are close together (high density), and in a rarefaction, particles are spread apart (low density). These density variations create pressure variations that travel as sound waves. Heat, light, and temperature are not the causes.
Q32. Rarefaction is a region of
Rarefaction is a region of low pressure and low density. It is formed when the vibrating object moves backward, pulling particles away from each other. The reduced density results in lower pressure compared to the normal pressure of the medium.
Q33. Which statement is true about sound propagation?
In sound propagation, only the disturbance (wave) moves forward. The particles of the medium do not move forward permanently; they vibrate about their mean positions and transfer the disturbance to neighbouring particles. The medium itself does not travel with the wave.
Q34. Sound waves transfer
Sound waves transfer energy from one point to another without transferring matter. The particles of the medium vibrate and pass the energy along. Sound does not transfer matter, medium, or particles; it only transfers energy.
Q35. In sound waves, particles move
In sound waves (longitudinal waves), particles move parallel to the direction of wave propagation. This back-and-forth motion creates compressions and rarefactions. In transverse waves, particles move perpendicular to the direction of wave propagation.
Q36. The loudness of sound depends on
The loudness of sound depends on the amplitude of vibration. Larger amplitude means louder sound. The medium and speed of sound affect how sound travels, but loudness is directly related to the amplitude of the vibrating object.
Q37. Sound can be produced by
Sound can be produced by plucking (strings), blowing (wind instruments), and striking (drums). All these methods cause vibrations, which produce sound. Any action that creates vibration can produce sound.
Q38. More density of particles means
More density of particles means more pressure because the particles are crowded together, colliding more frequently. In a compression, density is high, and so is pressure. In a rarefaction, density is low, and pressure is low.
Q39. Which of the following best describes sound?
Sound is best described as mechanical energy. It is a form of energy that travels through a medium as a mechanical wave. Sound is not matter, chemical energy, or light. It is the energy of vibrating particles.
Q40. Sound waves are called mechanical waves because
Sound waves are called mechanical waves because they need a material medium to travel. Unlike electromagnetic waves (like light), mechanical waves cannot travel through a vacuum. Sound requires particles to transfer energy.
Q41. Sound waves travel through air as
Sound waves travel through air as longitudinal waves. In longitudinal waves, the particles of the medium vibrate parallel to the direction of wave propagation. This creates alternating compressions and rarefactions. Transverse waves are not formed in air for sound.
Q42. When an object vibrates, it makes the surrounding particles
When an object vibrates, it makes the surrounding particles vibrate. These particles then transfer the vibration to neighbouring particles, propagating the sound wave. The particles do not change colour, stop moving, or heat up significantly.
Q43. Sound energy is transferred through
Sound energy is transferred through matter (a material medium). Sound requires particles to transfer energy. It does not travel through heat, light, or electricity as their primary mechanism. Sound is a mechanical wave that moves through matter.
Q44. Sound reaches us because
Sound reaches us because the disturbance (wave) travels through the medium. The particles of the medium do not travel to our ears; they only vibrate and pass the disturbance along. The wave carries the energy from the source to our ears.
Q45. Pressure in a medium depends on
Pressure in a medium depends on the number of particles per unit volume (density). Higher density means more particles, leading to more collisions and higher pressure. Size, shape of container, and colour do not affect pressure directly.
Q46. The substance through which sound travels is called
The substance through which sound travels is called the medium. The medium can be solid, liquid, or gas. The source produces the sound, the wave is the disturbance, and the receiver detects the sound. The medium is what carries the sound wave.
Q47. When a tuning fork vibrates in air, it produces sound due to
When a tuning fork vibrates in air, it produces sound due to the compression and rarefaction of air particles. The vibrating prongs push air particles together (compression) and pull them apart (rarefaction), creating sound waves that travel through the air.
Q48. Sound is an example of
Sound is an example of energy. It is a form of mechanical energy that travels through a medium. Sound is not matter, force (though it can exert force), or mass. It is the energy transferred by vibrating particles.
Q49. The mirror in the experiment moves because
In the tin-can experiment, the mirror moves because sound causes the balloon (and mirror) to vibrate. The sound waves from the source hit the balloon, causing it to vibrate, which makes the attached mirror move. This demonstrates that sound can cause vibrations.
Q50. The sound of the human voice is produced by vibrations in the
The sound of the human voice is produced by vibrations in the vocal cords (located in the larynx or voice box). When air from the lungs passes through the vocal cords, they vibrate, producing sound. The tongue, lungs, and teeth help shape the sound but do not produce the initial vibrations.