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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
Does sound follow the same laws of reflection as light does? Explain.
Name three devices which work on the reflection of sound.
Fill in the blank with suitable word :
An echo is simply a ................... sound.
On which day, a hot day or a cold day, an echo is heard sooner ? Give reason for your answer.
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.
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.
State the laws of reflection of sound.
What is an echo ? How is echo formed ?
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.
A man is kidnapped, blindfolded and imprisoned in a big room. How could the man tell if he was in : a bare room
Which of the following device does not work on the multiple reflections of sound waves ?
Explain by giving a scientific reason.
We cannot hear the echo produced in a classroom.
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?
What are the medical applications of echo?
______ is an image obtained by the use of reflected ultrasonic waves.
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.
Answer the following question in your own words.
What factors are important to get a distinct echo?
