Advertisements
Advertisements
Question
Answer the following question in your own words.
What factors are important to get a distinct echo?
Solution
- 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
RELATED QUESTIONS
What is meant by an echo?
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 ?
Name the device which is used to address a small gathering of people.
Fill in the blank with suitable word :
Echoes are caused by the ...................... of sound.
Why do we hear more clearly in a room with curtains than in a room without curtains ?
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 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
A man is kidnapped, blindfolded and imprisoned in a big room. How could the man tell if he was in : a furnished 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.
Answer the following question in your own words.
What is an echo?
State two conditions necessary for hearing an echo.
What are the medical applications of echo?
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.
