Advertisements
Advertisements
प्रश्न
Answer the following question in your own words.
What factors are important to get a distinct echo?
Advertisements
उत्तर
- Ambient temperature and the distance between the sound source and the reflecting surface are two factors that are important in the formation of echoes.
- The speed of sound in air at 22°C is 344 m/s. Our brain retains a sound for 0.1 seconds, so only if the sound reaches the barrier and reaches the listener's ears after more than 0.1 seconds will we hear it as a separate sound.
- Distance = Speed × Time
= 344 m/sec × 0.1 sec
= 34.4 m
Thus, the distance from the source of the sound to the obstacle and back to the source is the distance that the sound must travel at least 34.4 m. - So the minimum distance from the sound source to the obstacle should be half of the above distance i.e. 17.2 meters to hear a clear echo.
- These distances are different at different temperatures.
APPEARS IN
संबंधित प्रश्न
The minimum distance between the source and the reflector in air. So that an echo is heard is approximately equal to ______.
Explain why, the flash of lightning reaches us first and the sound of thunder is heard a little later.
Which of the following statement best describes frequency?
Which property of sound leads of the formation of echoes ?
On which day, a hot day or a cold day, an echo is heard sooner ? Give reason for your answer.
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 ?
Why are the ceilings of concert halls made curved ? Draw a labelled diagram to illustrate your answer.
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 ?
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.
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?
What is an echo?
State two conditions necessary for hearing an 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 ______.
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
