Advertisements
Advertisements
प्रश्न
What is an echo ? How is echo formed ?
Advertisements
उत्तर
The repetition of sound caused by the reflection of sound is called echo. An echo is produced when sound is reflected from a hard surface such as a tall brick wall or a cliff.
संबंधित प्रश्न
A man is standing at a distance of 12 m from a cliff. Will he be able to hear a clear echo of his sound? Give a reason for your answer.
Explain why, the flash of lightning reaches us first and the sound of thunder is heard a little later.
What is the other name of a loud-hailer ?
Fill in the blank with suitable word :
An echo is simply a ................... sound.
Why do we hear more clearly in a room with curtains than in a room without curtains ?
Why are the ceilings of concert halls made curved ? Draw a labelled diagram to illustrate your answer.
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 ?
Answer the following question in your own words.
What should be the dimensions and the shape of classrooms so that no echo can be produced there?
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?
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.
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.
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
