When a sound is reflected from a distant object, an echo is produced. Let the distance between the reflecting surface and the source of sound production remains the same. Do you hear echo sound on a hotter day?


As the temperature increases, the speed of the sound also increases.

Hence, the speed of sound on a hotter day is more.


We know that, echo occurs when time difference between original sound and reflected sound is atleast 0.1 second.



Speed = Distance / Time

Time = Distance / Speed


Therefore, for same distance, if speed is higher,

time taken would be less.



If the time would be less than 0.1 second, then the echo won’t be heard.

If the time would be more than or equal to 0.1 second, then the echo can be heard.

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  1. Class 9
  2. Chapter 12 Class 9 - Sound

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.