Advertisements
Advertisements
प्रश्न
Explain by giving a scientific reason.
We cannot hear the echo produced in a classroom.
Advertisements
उत्तर
- An echo is a sound produced when the original sound is reflected by the walls of a given room. For instance, in a small room If there are hard walls there will be an echo of sound bouncing off the wall but because the sound bouncing is so close to the original, it is harder to detect the echo produced.
- A room which is having a dimension greater than 17.2 m will produce an echo in that room.
- The dimensions of a classroom usually do not exceed 17.2 m, so echo is not produced in a classroom. So, in the case of a classroom, no echo is produced in a classroom.
APPEARS IN
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?
What is meant by an echo?
The minimum distance between the source and the reflector in air. So that an echo is heard is approximately equal to ______.
Which of the following statement best describes frequency?
Name three devices which work on the reflection of sound.
Fill in the blank with suitable word :
Echoes are caused by the ...................... of sound.
In which medium, air or water, an echo is heard much sooner ? Why ?
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.
Name any two objects which are good reflectors of sound.
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 ?
Answer the following question in your own words.
What is an echo?
State two conditions necessary for hearing an echo.
How can you calculate the speed of sound using echo?
______ allows bats to navigate through dark caves and find insects for food.
Assertion: The sound which we hear again is called Echo.
Reason: The sensation of sound (Echo) persists in our brain for about 1 s.
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?
Answer the following question in your own words.
What factors are important to get a distinct echo?
