Olympiad Test: Sound - Class 8 MCQ

the sound producing organ of our body is larynx or the voice box and ear drum is not a part of it.We also know that ear drum is not a part of skeletal system skeletal system consists of bones and joints .We also know that eardrum is not a part of reproductive system. So show the option remains is the hearing organ and we know that the hearing organ of our body is ear and it has the eardrum which senses the vibrations and convert it into signals and transmit it to brain with the help of afferent nerves. So option "c"is the correct answer.

The voice box is also called the larynx.
The larynx, commonly known as the voice box, is an organ located in the neck that plays a crucial role in producing sound and enabling speech. It is responsible for protecting the airway during swallowing and preventing food or liquid from entering the lungs.
Key Points:
- The voice box is also known as the larynx.
- The larynx is an organ located in the neck.
- It is responsible for producing sound and enabling speech.
- The larynx protects the airway during swallowing.
- It prevents food or liquid from entering the lungs.

When the amplitude of vibration of Steel tumbler is large, the sound produced is very loud. The loudness of sound depends on the amplitude of vibration of sound producing objects.
a)When the amplitude of vibration is large ,the sound produced is loud.

Pitch is equal to frequency when there is no relative motion between the source and the listener.

Sound is a kind of energy:
- Sound is a form of energy that is produced by vibrating objects.
- When an object vibrates, it creates sound waves that travel through the air or other mediums.
- Sound energy is a type of mechanical energy because it involves the movement of particles in the medium through which it travels.
- The energy of sound is transferred from the vibrating source to the surrounding particles, causing them to vibrate as well.
- The energy in sound waves can be measured in units such as decibels (dB).
- Sound energy can be converted into other forms of energy, such as electrical energy in a microphone or mechanical energy in a speaker.
- The intensity or loudness of sound is related to the amount of energy it carries.
- The pitch or frequency of sound is related to the speed at which the vibrations occur.
- Sound waves can be reflected, refracted, absorbed, or transmitted depending on the properties of the medium they encounter.
- Sound energy is essential for communication and allows us to perceive and interpret the world around us through hearing.
In conclusion, sound is a type of energy that is produced by vibrating objects and travels through a medium. It plays a crucial role in our daily lives and is involved in various phenomena and processes.

To and fro motion of an object is called vibration. Here is a detailed explanation of why the answer is C.
Definition of Vibration:
Vibration refers to the back and forth or oscillatory motion of an object or a particle about a fixed point.
Characteristics of Vibration:
- Vibration involves the repeated movement of an object or a particle from its original position to a new position and then back to its original position.
- It occurs in a regular pattern, with the object or particle moving back and forth in a predictable manner.
Examples of Vibration:
- A pendulum swinging back and forth.
- A guitar string vibrating when it is plucked.
- The motion of a tuning fork when it is struck.
- The shaking of a mobile phone when it is set to vibrate mode.
Relation to Other Concepts:
- Waves: Vibration is closely related to waves, as waves are a result of the propagation of vibrations through a medium. However, vibration specifically refers to the oscillatory motion of an object or a particle, while waves involve the transfer of energy through a medium in the form of oscillations.
- Amplitude: Amplitude refers to the maximum displacement or distance from the equilibrium position during a vibration or wave. While amplitude is a characteristic of vibration and waves, it is not synonymous with vibration itself.
Conclusion:
In conclusion, the correct answer is C: vibration. Vibration represents the to and fro motion of an object or a particle, characterized by repeated movement in a regular pattern.

Answer is a because The airstream provides the energy for the vocal folds in the voice box to produce sound...the vibrate very fast from 100 to1000 times per second,depending on the pitch of sound we make.Pitch is determined by the length and tension of the vocal folds,which are controlled by muscles in the larynx.

Sound propogates maximum in solid. The reason is that the particles are more closer to each other in a solid so transfer of sound  energy is faster in solid than in liquid or gas. 

Effects of Noise Pollution on Humans, Cats, and Birds

Noise pollution refers to the excessive or disturbing noise that can have negative effects on the environment and living beings. It can be caused by various sources such as traffic, construction, industrial activities, and loud music. Here is a detailed explanation of how noise pollution affects humans, cats, and birds:

1. Humans:
- Exposure to high levels of noise pollution can have detrimental effects on human health and well-being.
- It can lead to various physical and psychological problems, including hearing loss, stress, anxiety, sleep disturbances, and cardiovascular issues.
- Prolonged exposure to noise pollution may also impair cognitive functions, affect learning abilities, and decrease productivity.
- It can cause irritability, annoyance, and reduced quality of life.
2. Cats:
- Cats have a more sensitive hearing range than humans, making them more susceptible to the harmful effects of noise pollution.
- Loud noises can startle and stress cats, leading to anxiety, nervousness, and behavioral changes.
- Prolonged exposure to noise pollution can negatively impact their overall well-being, including their sleep patterns and immune system.
3. Birds:
- Birds rely heavily on their hearing for communication, mating, and detecting predators.
- Noise pollution disrupts their natural patterns and can lead to communication breakdowns, affecting their ability to find mates and establish territories.
- It can also cause birds to abandon their nests and alter their migration patterns due to disturbance and stress.
- Noise pollution can interfere with their ability to detect predators, making them more vulnerable to attacks.
In conclusion, noise pollution is harmful to humans, cats, and birds. It can have detrimental effects on their physical health, mental well-being, and overall quality of life. Taking measures to reduce noise pollution is essential for the well-being and conservation of these living beings.

Sound cannot travel in a vacuum.
Explanation:
- In order for sound to travel, it requires a medium such as air, water, or solids. These mediums allow sound waves to propagate through them by vibrating particles or molecules.
- A vacuum, on the other hand, is an area devoid of matter and therefore lacks any medium for sound waves to travel through. This means that sound cannot propagate in a vacuum.
- In outer space, for example, where there is a vacuum, sound cannot be heard because there are no particles or molecules to carry the sound waves.
- The absence of a medium in a vacuum prevents the transmission of sound waves, making it impossible for sound to travel.
- This is why astronauts in space rely on other forms of communication, such as radio waves or visual signals, as sound cannot be transmitted in the vacuum of space.
- So, the statement "Sound can travel in a vacuum" is false.

Humans can generally sense sounds at frequencies between 20 and 20,000 cycles per second, or hertz (Hz)—although this range shrinks as a person ages. Prolonged exposure to loud noises within the audible range have long been known to cause hearing loss over time.

False

Sound can travel through solid materials. Here's a detailed explanation:
Propagation of Sound Waves
- Sound waves are mechanical waves that require a medium to travel through. They cannot travel through a vacuum as there is no medium to transmit the vibrations.
- However, sound waves can travel through various mediums like air, liquids, and solids.
How Sound Travels in Solids
- In solids, sound waves travel through the particles of the material by causing them to vibrate.
- The particles in a solid are closely packed, which allows for the efficient transfer of energy from one particle to another.
- The energy transfer through the solid leads to the propagation of sound waves.
Speed of Sound in Solids
- The speed of sound in solids is generally faster than in liquids and gases due to the higher density and elasticity of solids.
- Different materials have different speeds of sound depending on their properties.
Applications of Sound Waves in Solids
- Sound waves in solids are used in various applications such as ultrasound imaging, seismic exploration, and non-destructive testing.
- Ultrasound imaging uses sound waves to create images of the internal structures of the body.
- Seismic exploration uses sound waves to study and locate subsurface structures like oil and gas reserves.
- Non-destructive testing uses sound waves to inspect the integrity of solid materials without causing damage.
Therefore, the statement "The sound cannot travel in solid materials" is false. Sound waves can indeed travel through solid materials by causing the particles to vibrate and propagate the energy.

Explanation:
The statement mentioned is true. Here is a detailed explanation:
1. Sound and Vibrations:
- Sound is a form of energy that is produced when vibrations travel through a medium, such as air, water, or solids.
- Vibrations are the rapid back-and-forth movements of particles or objects, which create waves that transfer energy.
2. Propagation of Vibrations:
- When an object vibrates, it causes neighboring particles or objects to vibrate as well.
- These vibrations are transmitted through the medium in a wave-like manner, resulting in the propagation of sound.
3. How Sound Propagates:
- As the vibrating object moves back and forth, it compresses and rarefies the surrounding particles or molecules in the medium.
- This creates a series of compressions and rarefactions, forming a sound wave.
- The sound wave then travels through the medium, with particles oscillating around their equilibrium positions.
4. Characteristics of Sound:
- Sound waves have several characteristics, including frequency, wavelength, amplitude, and speed.
- The frequency determines the pitch of the sound, while the amplitude determines its loudness.
- The wavelength represents the distance between two consecutive compressions or rarefactions.
5. Perception of Sound:
- When sound waves reach our ears, they cause the eardrums to vibrate.
- These vibrations are then transmitted to the inner ear, where they are converted into electrical signals that are sent to the brain.
- The brain interprets these signals as sound, allowing us to perceive and understand it.
In conclusion, the statement is true as sound is indeed caused by the propagation of vibrations through a medium.

Explanation:
The statement "The pitch of a sound depends on the frequency of the waves" is True. Here's why:
Pitch and Frequency:
- Pitch refers to how high or low a sound is perceived by the human ear.
- Frequency, on the other hand, is the number of complete waves that pass a point in a given amount of time.
- The pitch of a sound is directly related to its frequency.
Relationship between Pitch and Frequency:
- Higher pitch sounds have a higher frequency, meaning they have more waves passing a point in a given amount of time.
- Lower pitch sounds have a lower frequency, meaning they have fewer waves passing a point in a given amount of time.
Key points:
- The pitch of a sound is primarily determined by the frequency of the waves it produces.
- The higher the frequency, the higher the pitch, and vice versa.
- For example, a high-pitched sound like a whistle has a higher frequency compared to a low-pitched sound like a bass drum.
- The human ear can perceive a wide range of pitches, from low frequencies (deep bass) to high frequencies (high soprano).
Conclusion:
In summary, the pitch of a sound is indeed dependent on the frequency of the waves. Higher frequency waves produce higher pitch sounds, while lower frequency waves produce lower pitch sounds.

The correct option is A.
Ghatam, large, narrow-mouthed earthenware water pot used as a percussion instrument in India. Unlike other Indian percussion instruments, such as the tabla and mridangam, the ghatam does not have a membrane over its mouth.

Sound propagation without a medium - False

Sound is a form of mechanical wave that requires a medium to propagate. This means that sound cannot travel through a vacuum, as there is no medium for the sound waves to pass through. Therefore, the statement that sound does not need a medium for propagation is false.

Explanation:

• Definition of sound: Sound is a mechanical wave that is created by vibrating objects and travels through a medium as a series of compressions and rarefactions.


• Medium requirement: Sound waves require a medium, such as air, water, or solids, to travel through. The particles of the medium vibrate in response to the sound wave, transmitting the energy from the source to the receiver.


• Air as a common medium: In everyday life, sound waves commonly travel through air. The vibrations of an object, such as a drum or vocal cords, create compressions and rarefactions in the air, which propagate as sound waves.


• No propagation in a vacuum: In a vacuum, such as outer space, there is no medium for the sound waves to travel through. As a result, sound cannot propagate in a vacuum.


• Alternate propagation methods: While sound waves cannot travel through a vacuum, other forms of waves, such as electromagnetic waves (e.g., light waves) or radio waves, can propagate in a vacuum.

Therefore, sound waves require a medium to propagate, and the statement that sound does not need a medium for propagation is false.

The commonly used unit for the no. Of oscillations  per second is the  Hertz.
So, the given statement is false

The shrillness of sound is pitch. The pitch of the sound depends on the frequency of vibrations. The higher the frequency, the more shrill is the sound.

The loudness of sound is measured in units called  decibel (dB) . A decibel unit expresses the relative intensity if sounds on a scale from zero for the average least perceptible sound to about 100 dB, which is near the level most people find uncomfortably loud.