Echo
Echo
Echo: When a person shouts in a big empty hall, we first hear his original sound, after that we hear the reflected sound of that shout. This reflected sound is an echo. An echo is nothing but just the reflected sound. So, the repetition of sound caused by reflection of sound waves is called an echo. The sensation of sound persists in our brain for about 0.1 s. To hear a distinct echo, the time interval between the original sound and the reflected one must be atleast 0.1 s. The speed of sound in air is 344 m/sec. The distance travelled by the sound in 0.1 s = speed x time = 344 x 0.1 = 34.4 m
So, echo will be heard, if the minimum distance between the source of sound and the obstacle is = .
Conditions for the formation of Echoes
Q. A man stands in between two cliffs x and y, such that he is at a distance of 66 m from x. When he blows a whistle he hears first echo after 0.4 s and second echo after 1.2 s. Calculate: (i) speed of sound (ii) distance of the cliff y from man.
Solution: (i) Speed of sound
(ii) Distance of man from cliff
An echo returned in 0.3 s. What is the distance of the reflecting surface from the source of sound ? (Speed of sound is | |||
| Right Option : D | |||
| View Explanation | |||
Echo is a type of : | |||
| Right Option : A | |||
| View Explanation | |||
To hear a distinct echo, the minimum distance of a reflecting surface should be: | |||
| Right Option : A | |||
| View Explanation | |||
Students / Parents Reviews [10]
Abhyas is a complete education Institute. Here extreme care is taken by teacher with the help of regular exam. Extra classes also conducted by the institute, if the student is weak.
Om Umang
10thBeing a parent, I saw my daughter improvement in her studies by seeing a good result in all day to day compititive exam TMO, NSO, IEO etc and as well as studies. I have got a fruitful result from my daughter.
Prisha Gupta
8thMy experience was very good with Abhyas academy. I am studying here from 6th class and I am satisfied by its results in my life. I improved a lot here ahead of school syllabus.
Ayan Ghosh
8thIt was good as the experience because as we had come here we had been improved in a such envirnment created here.Extra is taught which is beneficial for future.
Eshan Arora
8thMy experience with Abhyas academy is very good. I did not think that my every subject coming here will be so strong. The main thing is that the online tests had made me learn here more things.
Hiya Gupta
8thAbhyas Methodology is very good. It is based on according to student and each child manages accordingly to its properly. Methodology has improved the abilities of students to shine them in future.
Manish Kumar
10thI have spent a wonderful time in Abhyas academy. It has made my reasoning more apt, English more stronger and Maths an interesting subject for me. It has given me a habbit of self studying
Yatharthi Sharma
10thIt has a great methodology. Students here can get analysis to their test quickly.We can learn easily through PPTs and the testing methods are good. We know that where we have to practice
Barkha Arora
10thIt was a good experience with Abhyas Academy. I even faced problems in starting but slowly and steadily overcomed. Especially reasoning classes helped me a lot.
Cheshta
10thMy experience with Abhyas is very good. I have learnt many things here like vedic maths and reasoning also. Teachers here first take our doubts and then there are assignments to verify our weak points.
