Because of high concentration of reflected sound at the Sound foci, there is a deficiency of reflected sound at some poi…

Which of the following relations between loudness and intensity is correct?

The formation of _______ takes place when the reflecting surfaces are situated at a distance greater than 17 M or so.

The absorption ratio of a surface is the ratio of _______

The rate of ventilation depends on both the wind effect and the stack effect.

The rate of flow through an opening due to the wind blowing on the wall containing it is given by the expression _______

For atmospheric air medium, the sound velocity at 20°C is about ____

Which of the following is not a characteristic of sound?