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Flash and thunder are produced simultane...

Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen, why ?

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The speed of sound (344 m/s) is less than the speed of light(`3xx10^(8)` m/s). Sound of thunder takes more time to reach the Earth as compared to light. Hence, a flash is seen before we hear a thunder.
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NCERT ENGLISH-SOUND -Exercise
  1. Cite an experiment to show that sound needs a material for its propaga...

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  2. Why is sound wave called a longitudinal wave ?

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  3. Which characteristic of the sound helps you to identify your friend by...

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  4. Flash and thunder are produced simultaneously. But thunder is heard a ...

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  5. A person has a hearing range from 20 Hz to 20 kHz. What are the typica...

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  6. Two children are at opposite ends of an aluminium rod. One strikes the...

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  7. The frequency of a source of sound is 100 Hz. How many times does it v...

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  8. Does sound follow the same laws of reflection as light does ? Explain.

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  9. When a sound is reflected from a distant object, an echo is produced. ...

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  10. Give two practical applications of reflection of sound waves.

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  11. A stone is dropped from the top of a tower 500 m high into a pond of w...

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  12. A sound wave travels at a speed of 339 m//s. If its wavelength is 1.5 ...

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  13. What is reverberation ? How can it be reduced ?

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  14. What is loudness of sound ? What factors does it depend on ?

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  15. Explain how bats use ultrasound to catch a prey.

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  16. How is ultrasound used for cleaning ?

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  17. Explain the working and application of a sonar.

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  18. A sonar device on a submarine sends out a signal and receives an echo ...

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  19. Explain how defects in a metal block can be detected using ultrasound.

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  20. Explain how the human ear works.

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