Physics Sound Part 13 (Sound wave: Wavelength & loudness) Class 8 VIII | Summary and Q&A

TL;DR
This video explains the concept of wavelength in sound waves and how loudness is related to amplitude.
Key Insights
- 👋 Waves consist of crests (peaks) and troughs (valleys), forming the structure of a wave.
- 🤒 Wavelength is the distance between two crests or troughs in a wave and can be measured in meters.
- 👂 Loudness is directly proportional to the square of the amplitude of vibration that produces the sound.
Transcript
Read and summarize the transcript of this video on Glasp Reader (beta).
Questions & Answers
Q: What is the crest and trough in a wave?
The crest is the peak of a wave, while the trough is the valley of the wave.
Q: How do crests and troughs form in a wave?
Crests are caused by compression regions of the medium, while troughs are formed by rarefaction regions.
Q: How is wavelength defined?
Wavelength is the distance between two consecutive crests or troughs in a wave.
Q: Can the entire distance covered by one wave be referred to as the wavelength?
Yes, the entire distance covered by one wave, including all the crests and troughs, is termed as the wavelength.
Q: How is loudness related to amplitude?
Loudness is directly proportional to the square of the amplitude of vibration that produces the sound.
Q: If the amplitude of vibration doubles, how does loudness change?
If the amplitude doubles, the loudness will increase by four times. Similarly, if the amplitude becomes three times, the loudness will increase by nine times.
Q: What is the loudness in different everyday sounds?
The sound of horns during traffic is around 70 decibels, normal conversation is around 60 decibels, whispering is around 30 decibels, and breathing is around 10 decibels.
Summary & Key Takeaways
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Waves have crests (upper portion) and troughs (lower portion), which form the basic structure of a wave.
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Wavelength is the distance between two consecutive crests or troughs in a wave.
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Loudness is directly proportional to the square of the amplitude of vibration that produces the sound.
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