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प्रश्न
On which day, a hot day or a cold day, an echo is heard sooner ? Give reason for your answer.
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उत्तर
An echo is heard sooner on a hot day because the speed of sound in air increases with increase in temperature of the propagating medium. Therefore, the speed of sound in air is faster on a hot day and thus echo is heard sooner.
संबंधित प्रश्न
The minimum distance between the source and the reflector in air. So that an echo is heard is approximately equal to ______.
Which of the following statement best describes frequency?
Name the device which is used to address a small gathering of people.
Fill in the blank with suitable word :
Echoes are caused by the ...................... of sound.
The echo of a sound is heard after 5 seconds. If the speed of sound in air be 342 m/s, calculate the distance of the reflecting surface.
The speed of sound in water is 1500 metres per second. How far away from an under-sea rock should a deep sea diver be so that he can hear his own echo ?
Name any two objects which are good reflectors of sound.
A man is kidnapped, blindfolded and imprisoned in a big room. How could the man tell if he was in : a furnished room
An echo-sounder in a trawler (fishing boat) receives an echo from a shoal of fish 0.4 s after it was sent. If the speed of sound in water is 1500 m/s, how deep is the shoal ?
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 is an echo?
What is an echo?
State two conditions necessary for hearing an echo.
______ allows bats to navigate through dark caves and find insects for food.
Assertion: The sound which we hear again is called Echo.
Reason: The sensation of sound (Echo) persists in our brain for about 1 s.
Numerical problems:
An echo returned in 3s. What is the distance of the reflecting surface from the source given that the speed of sound is 330 ms-1?
