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

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Chapter 11

NCERT

Class 9

Science

Solutions

5. Flash and Thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen. Why?

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Question:

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

Answer:

Since, the speed of sound is much less than the speed of light. That is why thunder and flash are produced simultaneously. But thunder is heard a few seconds after the flash is seen.

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Difference between Loudness and Intensity

Loudness	Intensity
Loudness is the measure of the sensitivity of the ear to sound which can differentiate between loud and soft sounds.	The amount of sound energy passing through a unit area in one second is called the intensity of sound.
Loudness may be different for different observers who depend on the sensitivity of the ears.	It does not depend on the sensitivity of the ears.
It’s unit is decibel (dB).	Its unit is watt/m2.

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(All Q's of this Chapter solved)

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