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
The minimum distance between source of sound and reflecting body is ________________ . | |||
| Right Option : A | |||
| View Explanation | |||
A boy standing 70 m from a high wall claps his hands. After how much time is an echo heard ? ( The speed of sound in air is | |||
| Right Option : B | |||
| View Explanation | |||
An echo is heared from a distant cliff after an interval of 2 secs. If the speed of sound in air is 340m/s, calculate the distance of the cliff. | |||
| Right Option : B | |||
| View Explanation | |||
Students / Parents Reviews [10]
Being 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
8thOne of the best institutes to develope a child interest in studies.Provides SST and English knowledge also unlike other institutes. Teachers are co operative and friendly online tests andPPT develope practical knowledge also.
Aman Kumar Shrivastava
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
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
10thMy 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
8thA marvelous experience with Abhyas. I am glad to share that my ward has achieved more than enough at the Ambala ABHYAS centre. Years have passed on and more and more he has gained. May the centre flourish and develop day by day by the grace of God.
Archit Segal
7thMy 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
10thIt 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 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.
