Question

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

Answer 1

Hint
To know whether we can hear echo on a hot day if the distance between the reflecting surface and the source of sound production remains the same. We should think of how the temperature affects the speed of sound.

Complete step by step answer
Sound is produced through the vibration of particles. While moving back and forth the particles bump into each other and produce sound. These particles result in a formation of mechanical waves known as sound waves. Sound is a sequence of waves of pressure that propagates through compressible media like air liquid and solid. During the propagation of sound waves the waves are refracted, reflected and altered by the medium by which it travels.
If we make a sound or shout near a tall building or a mountain, we will hear the same sound again a little later. This sound that we hear is called an echo. The sensation of sound is prolonged in our brain for about 0.1 s. To hear a distinct echo the time period between the original sound and the reflected sound must be at least 0.1s.
For hearing distinct echoes, the minimum distance between the obstacle and the source of sound must be half of the distance covered in the whole process of reflection. This distance will change if there is a change in the temperature of air. The speed of sound in a medium depends on the temperature of the medium whether it is solid or liquid or air. In any medium if we increase the temperature the speed of sound will increase. This happens because air molecules have more energy at higher temperatures, which means their vibration increases when the temperature increases. This makes the sound waves to travel faster because the sound waves are propelled by collisions between the molecules.
It is true that on a hot day the speed of the sound increases, the time interval between the original sound and the reflected one must be at least 0.1s even on a hot day. Let us say the distance between the reflecting surface and the source of sound production remains the same, if the time taken by the echo to reflect back is less than or equal to .01s we can hear the echo, if it is more than 0.1s then we cannot hear the echo.

Note
Echoes may be heard more than once because of the successive or multiple reflections. The rolling of thunder is heard due to the successive reflections of the sound waves from a number of reflecting surfaces, such as the clouds and land.