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प्रश्न
Explain why, the flash of lightning reaches us first and the sound of thunder is heard a little later.
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उत्तर
Since light travels faster than sound, the flash of lightning is seen first and the sound of thunder is heard thereafter.
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संबंधित प्रश्न
An echo returned in 3 s. What is the distance of the reflecting surface from the source, given that the speed of sound is 342 m s−1?
Name the device which is used to address a small gathering of people.
Fill in the blank with suitable word :
An echo is simply a ................... sound.
In which medium, air or water, an echo is heard much sooner ? Why ?
What is meant by 'reflection of sound' ? What type of surfaces are the best for reflecting sound ?
An echo-sounder in a trawler (fishing boat) receives an echo from a shoal of fish 0.4 s after it was sent. If the speed of sound in water is 1500 m/s, how deep is the shoal ?
Which of the following device does not work on the multiple reflections of sound waves ?
What is an echo? Write the conditions to hear an echo.
Numerical problems:
An echo returned in 3s. What is the distance of the reflecting surface from the source given that the speed of sound is 330 ms-1?
Rohan conducted experiments on echo in different media. He observed that a minimum distance of 'x' meters is required for the echo to be heard in oxygen and 'y' meters in benzene. Compare 'x' and 'y'. Justify your answer.
Speed of sound in oxygen: 340 ms-1
Speed of sound in benzene: 200 ms-1
