HOTS questions on 'Sound' for Class 8 Science
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Class 8 Science, Sound - Sample questions
These HOTS questions on 'Sound' for Class 8 will test the Higher Order Thinking Skills in Science of CBSE students and NSO Science Olympiad aspirants.
What is the difference between sound and noise?
Answer: Sound is a type of energy that is produced by the vibration of an object, while noise is a sound that is unwanted or unpleasant to hear.
How is the loudness of sound measured?
Answer: The loudness of sound is measured in decibels (dB) using a device called a sound level meter.
What is the relationship between frequency and pitch of sound?
Answer: Frequency is the number of vibrations per second, while pitch is the highness or lowness of a sound. The higher the frequency, the higher the pitch.
Why do we hear echoes?
Answer: We hear echoes when sound waves reflect off a hard surface and bounce back to our ears.
What is the difference between ultrasound and infrasound?
Answer: Ultrasound is sound with a frequency higher than the upper limit of human hearing, while infrasound is sound with a frequency lower than the lower limit of human hearing.
How is sound produced in musical instruments?
Answer: Sound is produced in musical instruments by the vibration of strings, membranes, or columns of air.
What is the Doppler effect?
Answer: The Doppler effect is the change in frequency of sound waves when the source or observer is moving.
How do animals use sound to communicate?
Answer: Many animals use sound to communicate, such as whales, dolphins, birds, and insects.
Why do sound waves travel faster in solids than in gases?
Answer: Sound waves travel faster in solids than in gases because the particles in solids are closer together, allowing sound waves to travel more quickly.
How do noise-cancelling headphones work?
Answer: Noise-cancelling headphones work by producing sound waves that cancel out external noise.
How does the ear convert sound waves into electrical signals?
Answer: The ear converts sound waves into electrical signals through a complex process involving the eardrum, middle ear, and inner ear.
What is resonance, and how is it used in music?
Answer: Resonance is the natural tendency of an object to vibrate at its natural frequency. It is used in music to produce a richer, fuller sound.
How do we localize sound?
Answer: We localize sound by using the differences in arrival time and loudness between the two ears.
How can sound be used to treat medical conditions?
Answer: Sound can be used to treat medical conditions such as hearing loss, tinnitus, and pain.
What is the difference between white noise and pink noise?
Answer: White noise is a sound that contains equal energy at all frequencies, while pink noise is a sound that contains equal energy per octave.
What is the difference between sound intensity and sound pressure?
Answer: Sound intensity is the amount of energy per unit area of a sound wave, while sound pressure is the force exerted by a sound wave on a surface.
How does the speed of sound change with temperature?
Answer: The speed of sound increases with temperature because the particles in a medium move faster at higher temperatures.
How is sound used in sonar technology?
Answer: Sound is used in sonar technology to locate and identify objects underwater.
Class 8 Science, Sound - Problems
1. The frequency of a sound wave is 500 Hz. What is its wavelength if the speed of sound is 343 m/s?
a) 0.68 m
b) 0.69 m
c) 0.70 m
d) 0.71 m
Answer: b) 0.69 m
Explanation: Wavelength = speed of sound / frequency = 343 m/s / 500 Hz = 0.69 m
2. What is the wavelength of a sound wave with a frequency of 1000 Hz traveling through air at a speed of 340 m/s?
a) 0.34 m
b) 0.45 m
c) 0.68 m
d) 0.90 m
Answer: a) 0.34 m
Explanation: Wavelength = speed of sound / frequency = 340 m/s / 1000 Hz = 0.34 m
3. A sound wave with a frequency of 200 Hz has a wavelength of 1.7 m. What is its speed?
a) 340 m/s
b) 360 m/s
c) 380 m/s
d) 400 m/s
Answer: b) 360 m/s
Explanation: Speed of sound = wavelength x frequency = 1.7 m x 200 Hz = 340 m/s
4. A sound wave with a wavelength of 0.5 m has a speed of 340 m/s. What is its frequency?
a) 340 Hz
b) 680 Hz
c) 1020 Hz
d) 1360 Hz
Answer: b) 680 Hz
Explanation: Frequency = speed of sound / wavelength = 340 m/s / 0.5 m = 680 Hz
5. If the amplitude of a sound wave is doubled, what is the change in its intensity?
a) It is halved
b) It is doubled
c) It is quadrupled
d) It is increased by a factor of 8
Answer: c) It is quadrupled
Explanation: The intensity of a sound wave is proportional to the square of its amplitude. Doubling the amplitude results in a fourfold increase in intensity.
Class 8 Science, Sound - Revision notes
Sound is a form of energy that is produced by the vibration of an object.
Sound waves are longitudinal waves that travel through a medium.
The speed of sound varies with the medium through which it travels.
The loudness of sound is measured in decibels (dB), and the pitch of sound is measured in hertz (Hz).
The human ear is divided into three parts: the outer ear, middle ear, and inner ear.
The outer ear consists of the pinna and ear canal, which collect and direct sound waves to the eardrum.
The middle ear contains the three smallest bones in the body (hammer, anvil, and stirrup), which amplify and transmit sound waves to the inner ear.
The inner ear contains the cochlea, which converts sound waves into electrical signals that are sent to the brain.
Ultrasound is sound with a frequency higher than the upper limit of human hearing, while infrasound is sound with a frequency lower than the lower limit of human hearing.
The Doppler effect is the change in frequency of sound waves when the source or observer is moving.
Resonance is the natural tendency of an object to vibrate at its natural frequency. It is used in music to produce a richer, fuller sound.
Noise-cancelling headphones work by producing sound waves that cancel out external noise.
Sound can be used in sonar technology to locate and identify objects underwater.
Sound can be used to treat medical conditions such as hearing loss, tinnitus, and pain.
Sound waves reflect off surfaces and create echoes. Echoes can be used to determine the distance of an object from the source of sound.
Animals use sound to communicate with each other, such as whales, dolphins, birds, and insects.
Sound waves travel faster in solids than in liquids or gases because the particles in solids are closer together.
The human voice produces different sounds by changing the shape of the vocal cords and the resonant cavities of the throat and mouth.
Sound waves can be diffracted, refracted, and scattered when they encounter different media.
Sound is an important tool for measuring distances, detecting objects, and communicating information in a variety of contexts.
HOTS Questions on Sound for Class 8 - PDF
The HOTS questions in the pdf sample papers will help students of grade 8 to ace their CBSE exam and the "achiever's section" of Science Olympiads.
Try to solve the higher order thinking questions in the pdf sample paper below within 60 minutes. You also have the option of attempting these questions in online mode.
The answer key to the HOTS questions on 'sound' is shared at the end of the pdf. If you want to see the solutions, you need to take the online test series.
HOTS Questions on Sound for Class 8 - Online test
The maximum time allotted for this online test is 60 minutes. You will get to see your scorecard along with solutions on submission. You will also get an instant merit certificate for scores > 70%. All the best.
Class 8 Science, Sound - Results of Online test
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Extra questions - Class 8 Science - Sound
1. Sound waves are:
a) Electromagnetic waves
b) Longitudinal waves
c) Transverse waves
d) Mechanical waves
Answer: d) Mechanical waves
Explanation: Sound waves are mechanical waves, meaning they require a medium (such as air, water, or a solid) to travel through.
2. The speed of sound is fastest in:
a) Air
b) Water
c) Steel
d) Vacuum
Answer: c) Steel
Explanation: The speed of sound is fastest in solids such as steel, slower in liquids such as water, and slowest in gases such as air.
3. The pitch of a sound is related to its:
a) Amplitude
b) Frequency
c) Wavelength
d) Speed
Answer: b) Frequency
Explanation: The pitch of a sound is related to its frequency, with higher frequencies corresponding to higher pitches.
4. A sound wave with a high frequency would have a:
a) Short wavelength
b) Long wavelength
c) No wavelength
d) None of the above
Answer: a) Short wavelength
Explanation: The wavelength of a sound wave is inversely proportional to its frequency, meaning higher frequencies correspond to shorter wavelengths.
5. The unit of frequency is:
a) Hertz
b) Joules
c) Newtons
d) Watts
Answer: a) Hertz
Explanation: The unit of frequency is hertz (Hz), which represents the number of cycles or vibrations per second.
6. The amplitude of a sound wave is measured in:
a) Watts
b) Decibels
c) Hertz
d) Meters
Answer: b) Decibels
Explanation: The amplitude of a sound wave, which determines its loudness, is measured in decibels (dB).
7. The reflection of sound waves is called:
a) Diffraction
b) Refraction
c) Reflection
d) Interference
Answer: c) Reflection
Explanation: The reflection of sound waves occurs when the waves bounce off a surface, such as a wall or a ceiling.
8. The bending of sound waves as they pass through a medium is called:
a) Reflection
b) Refraction
c) Diffraction
d) Interference
Answer: b) Refraction
Explanation: The refraction of sound waves occurs when they pass through a medium with a different density, causing them to bend.
9. The interference of sound waves can result in:
a) Constructive interference
b) Destructive interference
c) Both a and b
d) None of the above
Answer: c) Both a and b
Explanation: When sound waves interfere with each other, the resulting sound can either be louder (constructive interference) or quieter (destructive interference) than the individual sounds. This depends on whether the waves are in phase or out of phase with each other.
10. The lowest frequency that a human can hear is:
a) 20 Hz
b) 200 Hz
c) 2,000 Hz
d) 20,000 Hz
Answer: a) 20 Hz
Explanation: The range of human hearing is typically considered to be from 20 Hz to 20,000 Hz, with 20 Hz being the lowest frequency that can be heard.
11. Sound waves can travel through:
a) Air
b) Water
c) Steel
d) All of the above
Answer: d) All of the above
Explanation: Sound waves can travel through any medium, including air, water, and solids such as steel.
12. The frequency of a sound wave is measured in:
a) Decibels
b) Hertz
c) Meters
d) Watts
Answer: b) Hertz
Explanation: The frequency of a sound wave is measured in hertz (Hz), which represents the number of cycles or vibrations per second.
13. The loudness of a sound is determined by its:
a) Frequency
b) Wavelength
c) Amplitude
d) Speed
Answer: c) Amplitude
Explanation: The loudness of a sound is determined by its amplitude, with larger amplitudes corresponding to louder sounds.
14. The sound produced by a vibrating object is called:
a) Noise
b) Echo
c) Sound wave
d) None of the above
Answer: c) Sound wave
Explanation: The sound produced by a vibrating object is in the form of a sound wave, which can travel through a medium such as air and be detected by the ear.
15. The wavelength of a sound wave is the:
a) Distance between two adjacent compressions or rarefactions
b) Distance between the source of the sound and the ear
c) Distance traveled by the sound wave per second
d) None of the above
Answer: a) Distance between two adjacent compressions or rarefactions
Explanation: The wavelength of a sound wave is the distance between two adjacent compressions or rarefactions, and is inversely proportional to the frequency of the wave.