Nature of sound : Sound is a mechanical and longitudinal wave. It needs material medium to propagate. It is produced by small and large pressure changes.
Speed of sound: Sound waves travel at different speeds in different substances. The speed of sound depends on various factors like temperature, nature and physical state of the substance, etc. for example, the speed of sound in air is about 3.30m/s at C and 346 m/s at room temperature. Also notice from table that sound waves travel fastest in solids and slowest in gases.
Substance | Speed (m/s) | Substance | Speed (m/s) |
Air | 346 | Aluminum | 5000 |
Water | 1498 | Iron | 5000 |
Mercury | 1452 | Diamond | 12,000 |
Glass | 5000 |
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Light, propagates faster than sound . All of us have, at one time or the other, been shaken and frightened by the roaring thunder sounds that follow flashes of lightning. The thundering sounds are always heard a little after seeing the flash of lightning. Why?
In early stages, people thought that we hear the thunder a little after seeing the lightning simply because the thunder perhaps occurred a little later. We now know that this is not the reason. Both lighting and thunder really occur together. The reason for the delay, in hearing the thunder, is due to the difference in the speeds of sound and light.
Measurement of the speed of light and sound tell us that light propagates very fast as compared to sound. The speed of sound in air is nearly 30 m/s (or 0.33 km per second) whereas speed of light is as high as 3 lakh kilometers per second. Light, thus, propagates nearly a million times faster than the sound. Hence, when lighting and thunder occur together, the flash of lighting (i.e. light) reaches us in practically zero time. The sound of the thunder however, takes a few seconds to reach us.
1 decible = _____ bell. | |||
Right Option : B | |||
View Explanation |
An underwater explosion is caused near the sea - shore. There are two observers, X under water and Y on land, each at a distance of 1 km from the point of explosion. Then , ____________________________________ | |||
Right Option : A | |||
View Explanation |
Sound tavels faster in ______ than in liquids. | |||
Right Option : A | |||
View Explanation |
One 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.
Abhyas institute is one of the best coaching institute in the vicinity of Ambala Cantt area. The teachers of the institute are well experienced and very helpful in solving the problems of the students.The good thing of the institute is that it is providing extra classes for the students who are w...
A 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.
The experience was nice. I studied here for three years and saw a tremendous change in myself. I started liking subjects like English and SST which earlier I ran from. Extra knowledge gave me confidence to overcome competitive exams. One of the best institutes for secondary education.
My 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.
It 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
It 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.
We started with lot of hope that Abhyas will help in better understnding of complex topics of highers classes. we are not disappointed with the progress our child has made after attending Abhyas. Though need to mention that we expected a lot more. On a scale of 1-10, we would give may be 7.
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Third consective year,my ward is in Abhyas with nice experience of admin and transport support.Educational standard of the institute recumbent at satisfactory level. One thing would live to bring in notice that last year study books was distributed after half of the session was over,though study ...
My 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.
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My experience with Abhyas Academy has been very good. When I was not in Abhyas whenever teacher ask questions I could not speak it confidently but when I came in Abhyas, my speaking skills developed and now I am the first one to give the answer of teachers question.
Abhyas institute is one of the best coaching institute in the vicinity of Ambala cantt.The institute provides good and quality education to the students.The teachers are well experienced and are very helpful in solving the problems. The major advantages of the institute is extra classes for weak...
Abhyas academy is great place to learn. I have learnt a lot here they have finished my fear of not answering.It has created a habit of self studying in me.The teachers here are very supportive and helpful. Earlier my maths and science was good but now it has been much better than before.
Usually we see institutes offering objective based learning which usually causes a lag behind in subjective examinations which is the pattern followed by schools. I think it is really a work of planning to make us students grab the advantages of modes of examination, Objective Subjective and Onli...
Abhyas 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.
In terms of methodology I want to say that institute provides expert guidence and results oriented monitering supplements by requsite study material along with regular tests which help the students to improve their education skills.The techniques of providing education helps the students to asses...
I 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