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प्रश्न
The echo of a sound is heard after 5 seconds. If the speed of sound in air be 342 m/s, calculate the distance of the reflecting surface.
उत्तर
We have to calculate the distance between the reflecting surface and the observer.
Given: Time taken to hear the echo t = 5 s.
So time taken for sound to reach the reflecting surface (`t_r`) = `5/2` s
Speed of sound in air ν = 342 m/s
Therefore, distance of reflecting surface from the observer is
= `(v) xx (t_r)`
= `(342) xx (5/2)` m
= 855 m
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संबंधित प्रश्न
Name the device which is used to address a small gathering of people.
State the laws of reflection of sound.
What is an echo ? How is echo formed ?
What is the minimum distance in air required from a sound reflecting surface to hear an echo (at 20°C) ?
A man standing 825 metres away from a cliff (steep rock) fires a gun. After how long will he hear its echo ? Speed of sound in air is 330 m/s.
Which of the following device does not work on the multiple reflections of sound waves ?
A man is standing between two vertical walls 680 m apart. He claps his hands and hears two distinct echoes after 0.9 seconds and 1.1 seconds respectively. What is the speed of sound in the air?
Assertion: The sound which we hear again is called Echo.
Reason: The sensation of sound (Echo) persists in our brain for about 1 s.
What is an echo? Write the conditions to hear an echo.
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
