Test your knowledge of "Sound" from Chapter 10 with this engaging Class 8 quiz! Perfectly designed for curious minds, it covers key concepts like vibrations, sound propagation, and the human ear. Sharpen your understanding with fun, thought-provoking questions tailored for learners. Whether revising for a test or exploring science, this quiz guarantees an interactive learning experience.
1) Why is sound important in our lives?
Answer: Sound plays an important role in our lives as it helps us communicate and allows us to hear a variety of sounds in our surroundings.
2) What sounds do you hear in the music room of your school?
Answer: In the music room, you hear sounds produced by musical instruments like the flute, tabla, and harmonium.
3) What happens when you touch the school bell when it is not in use and when it is producing sound?
Answer: When you touch the school bell when it is not in use, you feel nothing.
When you touch it while it is producing sound, you can feel it vibrating.
4) What is vibration, and how is it related to sound?
Answer: Vibration is the to-and-fro or back-and-forth motion of an object.
When a tightly stretched object (like a rubber band) is plucked, it vibrates and produces sound.
When the vibrations stop, the object no longer produces sound.
5) What is the vibrating part of a Veena?
Answer: The vibrating part of a Veena is a stretched string.
6) What is the vibrating part of a Tabla?
Answer: The vibrating part of a Tabla is a stretched membrane.
7) Can you name some musical instruments and what part vibrates to produce sound?
Answer: Here are some examples of musical instruments and their vibrating parts:
Piano: Strings
Guitar: Strings
Drum: Drumhead
Bell: Metal body
8) How is the Jaltrang instrument created?
Answer: The Jaltrang is created by filling 6-8 bowls or tumblers with different amounts of water, gradually increasing the water level from one end to the other. Gently striking each bowl with a pencil produces distinct musical notes.
9) What happens when you speak or sing loudly?
Answer: When you speak or sing loudly, you can feel vibrations in your throat.
10) What is the role of the voice box in sound production?
Answer: The voice box, or larynx, is the primary organ responsible for producing sound in humans.
11) How do vocal cords contribute to sound production?
Answer: Vocal cords, located within the larynx, vibrate when air is forced through them by the lungs, creating sound.
12) How do the muscles attached to the vocal cords affect the voice?
Answer: The muscles attached to the vocal cords play a crucial role in controlling the pitch and loudness of our voice. They achieve this by adjusting the tension, length, and thickness of the vocal cords, which directly influence how they vibrate when air passes through them.
13) How is the sound produced by a musical instrument different from just the vibration of its primary sound-producing part (e.g., string, membrane)?
Answers: The sound produced by a musical instrument is not solely from the primary vibrating part (like a string or membrane). The entire instrument vibrates, and its structure and material significantly contribute to the overall sound.
14) How does the sound produced by vocal cords change when they are loose and thick?
Answer: When the vocal cords are loose and thick, the sound produced is deeper and lower in pitch
15) How do the lengths of vocal cords differ between men, women, and children?
Answer: Men typically have longer vocal cords (around 20 mm) compared to women (around 15 mm). Children have the shortest vocal cords.
16) How does this difference in vocal cord length affect the voice?
Answer: The difference in vocal cord length is a primary factor in the variation of voices between men, women, and children. Longer vocal cords generally produce deeper voices.
17) How does sound travel from one person to another?
Answer: Sound travels through a medium, such as air, water, or solids. When you speak, sound waves travel through the air to reach the listener's ears.
18) What happens to the sound of the ringing cell phone when you surround the tumbler with your hands?
Answer: Sound travels through a medium, such as air, water, or solids. When you speak, sound waves travel through the air to reach the listener's ears.
19) What happens to the sound of the ringing cell phone when you suck air from the tumbler?
Answer: The sound of the ringing cell phone becomes fainter as you suck air from the tumbler.
20) What happens to the sound of the ringing cell phone when you remove the tumbler from your mouth?
Answer: The sound of the ringing cell phone becomes louder again when you remove the tumbler from your mouth.
21) Why does the sound of the ringing cell phone change when you suck air from the tumbler?
Answer: The decreasing loudness of the ring is likely due to the decreasing amount of air in the tumbler. Air is the medium through which sound travels, and as you remove air, the sound has fewer particles to travel through.
22) Can sound travel through a vacuum?
Answer: No, sound cannot travel through a vacuum. A vacuum is a space completely devoid of matter, including air. Since sound needs a medium to travel, it cannot propagate in a vacuum.
23) Can sound travel through liquids? How do you know?
Answer: Yes, sound can travel through liquids. You can hear the sound of the bell when your ear is placed on the water's surface, indicating that sound waves are transmitted through the water.
24) Can sound travel through solids? How do you know?
Answer: Yes, sound can travel through solids. You can hear the scratching or tapping sound at the other end of the meter scale, demonstrating that sound waves are transmitted through the metal.
25) How can you demonstrate that sound travels through solids?
Answer: You can place your ear at one end of a long wooden or metallic table and ask your friend to gently scratch the other end of the table.
26) Can sound travel through strings?
Answer: Yes, sound can travel through strings. This can be demonstrated by making a toy telephone using two tin cans and a string connecting them.
27) How does the outer part of the ear help in hearing?
Answer: The outer part of the ear is shaped like a funnel, which helps to collect sound waves and direct them into the ear canal.
28) What is the eardrum and what is its function?
Answer: The eardrum is a thin, stretched membrane located at the end of the ear canal. It vibrates in response to sound waves, transmitting these vibrations to the middle ear.
29) What are the mediums through which sound can travel?
Answer: Sound can travel through gases, liquids, and solids.
30) How does the eardrum help in hearing?
Answer: The eardrum is like a stretched rubber sheet. When sound waves reach the eardrum, they cause it to vibrate. These vibrations are then transmitted to the inner ear, and from there, the signals are sent to the brain, enabling us to hear.
31) What is the frequency of oscillation?
Answer: The number of oscillations per second is called the frequency of oscillation. It is expressed in hertz (Hz).
32) If an object oscillates 20 times in one second, what is its frequency?
Answer: The frequency of the object would be 20 Hz.
33) How can we recognize familiar sounds without seeing the objects producing them?
Answer: We can recognize familiar sounds based on their unique characteristics, such as their pitch and loudness.
34) What factors make different sounds distinguishable?
Answer: Two important properties that differentiate sounds are amplitude and frequency.
35) What is the to and fro motion of an object called?
Answer: The to-and-fro motion of an object is called vibration or oscillatory motion.
36) How can you demonstrate the relationship between the amplitude of vibration and the loudness of the sound?
Answer: Suspend a small thermocol ball touching the rim of the tumbler.
Vibrate the tumbler by striking it and observe the displacement of the ball. This displacement indicates the amplitude of the vibration.
Strike the tumbler gently and then a little harder.
Compare the amplitudes of vibration in both cases.
Determine in which case the amplitude is larger.
Remember that loudness of sound is directly proportional to the square of the amplitude of vibration.
37) How does the loudness of sound vary with the amplitude of vibration?
Answer: When the amplitude of the vibration is large, the sound produced is loud.
When the amplitude is small, the sound produced is feeble.
38) What is the relationship between the frequency of vibration and the pitch of a sound?
Answer: Frequency determines the shrillness or pitch of a sound.
Higher frequency results in a shriller sound with a higher pitch.
Lower frequency results in a lower pitch.
39) What is the difference between the sounds produced by a baby and an adult?
Answer: Even though two sounds might be equally loud, they can differ in their pitch.
This difference in pitch is often noticeable when comparing the voices of a baby and an adult.
40) What is the unit used to express the loudness of sound?
Answer: Decibel (dB) is the unit used to express the loudness of sound.
41) How does frequency affect the pitch of a sound?
Answer: Frequency determines the shrillness or pitch of a sound.
Higher frequency results in a shriller sound with a higher pitch (e.g., whistle).
Lower frequency results in a lower pitch (e.g., drum).
42) How do the voices of children and adults differ in terms of frequency?
Answer: Generally, the voice of a child has a higher frequency than that of an adult.
Typically, a woman's voice has a higher frequency than a man's voice.
43) What is the range of audible frequencies for humans?
Answer: The human ear can typically detect sounds within the range of 20 Hz to 20,000 Hz.
Sounds below 20 Hz (infrasound) and above 20,000 Hz (ultrasound) are inaudible to humans.
44) Can all vibrating bodies produce audible sounds?
Answer: No, not all vibrating bodies produce sounds audible to humans.
Sounds with frequencies below 20 Hz (infrasound) and above 20,000 Hz (ultrasound) are inaudible.
45) What are some examples of animals that can hear sounds beyond the human range?
Answer: Dogs can hear sounds of frequencies higher than 20,000 Hz (ultrasound).
46) What is noise pollution?
Answer: Noise pollution refers to the presence of excessive or unwanted sounds in the environment.
47) What are some major sources of noise pollution?
Answer: Major sources include vehicle sounds, explosions (like bursting crackers), industrial machinery, loudspeakers, and even loud household appliances like televisions and air conditioners.
48) What are the potential health effects of noise pollution?
Answer: Noise pollution can lead to various health problems, including lack of sleep, hypertension (high blood pressure), anxiety, and other health disorders.
Prolonged exposure to loud noise can cause temporary or even permanent hearing impairment.
49) How can we control noise pollution from its sources?
Answer: Installing silencing devices in aircraft engines, transport vehicles, industrial machines, and home appliances can significantly reduce noise levels.
50) What measures can be taken to control noise pollution in residential areas?
Answer: Noisy operations should be conducted away from residential areas.
Noise-producing industries should be established away from residential zones.
The use of automobile horns should be minimized.
TV and music systems should be played at low volumes.
Planting trees along roads and around buildings can help reduce noise levels reaching residents.
51) What are the causes of hearing impairment?
Answer: Total hearing impairment is usually present from birth.
Partial hearing disability can result from diseases, injuries, or age-related factors.
52) How can children with hearing impairment communicate effectively?
Answer: Learning sign language allows children with hearing impairment to communicate effectively.
53) How can society help individuals with hearing impairment?
Answer: Society can play a crucial role in improving the living environment for the hearing-impaired and helping them lead normal lives.
