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प्रश्न
Answer the following question in your own words.
What is an echo?
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उत्तर
An echo is the reflection of sound waves off a surface, such as a wall, mountain, or building, that returns to the listener after a delay. It occurs when the reflected sound reaches the ear after at least 0.1 seconds, allowing the listener to distinguish it from the original sound. Echoes are commonly experienced in large, empty spaces or near hard, smooth surfaces.
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संबंधित प्रश्न
What is meant by an echo?
Name three devices which work on the reflection of sound.
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 ?
Why do we hear more clearly in a room with curtains than in a room without curtains ?
The speed of sound in water is 1500 metres per second. How far away from an under-sea rock should a deep sea diver be so that he can hear his own echo ?
What is meant by 'reflection of sound' ? What type of surfaces are the best for reflecting sound ?
Name any two objects which are good reflectors 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) ?
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 ?
What are the medical applications of echo?
When sound is reflected from a distant object, an echo is produced. Let the distance between the reflecting surface and the source of sound remain the same. Do you hear an echo sound on a hotter day? Justify your answer.
To hear an echo, the minimum distance of the obstacle from the source of sound must be ______.
______ is an image obtained by the use of reflected ultrasonic waves.
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
