Advertisements
Advertisements
प्रश्न
The minimum distance between the source and the reflector in air. So that an echo is heard is approximately equal to ______.
The minimum distance between the source and the reflector in air, to hear an echo, is approximately ______.
विकल्प
10 m
17 m
34 m
50 m
Advertisements
उत्तर १
The minimum distance between the source and the reflector in air. So that an echo is heard is approximately equal to 17 m.
Explanation:
An echo is heard distinctly if it reaches the ear at least 0.1 s after the original sound.
If d is the distance between the observer and the obstacle and V is the speed of sound, then the total distance travelled by the sound to reach the obstacle and then to come back is 2d and the time taken is,
t = `"Total distance travelled"/"Speed of sound" = "2d"/V`
or, d = `(V t)/2`
Putting t = 0.1 s and V = 340 m/s in air at ordinary temperature, we get:
d = `(340 xx 0.1)/2`
d = 17 m
Thus, to hear an echo distinctly, the minimum distance between the source and the reflector in air is 17 m.
उत्तर २
The minimum distance between the source and the reflector in air, to hear an echo, is approximately 17 m.
APPEARS IN
संबंधित प्रश्न
Does sound follow the same laws of reflection as light does? Explain.
The frequencies of four sound waves are given below. Which of these sound waves can be used to measure the depth of sea by the echo method ?
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 are the medical applications of echo?
How can you calculate the speed of sound using 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 ______.
Assertion: The sound which we hear again is called Echo.
Reason: The sensation of sound (Echo) persists in our brain for about 1 s.
Answer the following question in your own words.
What factors are important to get a distinct echo?
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
