Reverberation is a phenomenon associated with a

CONCEPT:

Reverberation:

• This persistence of sound in a closed enclosure, due to continuous reflections at the walls or the floor or the ceiling of the enclosure, even after the source has stopped producing sound is known as 'reverberation'.

EXPLANATION:

• From the above, it is clear that the persistence of sound in a closed enclosure, due to multiple reflections at the walls or the floor or the ceiling of the enclosure, even after the source has stopped producing sound is known as 'reverberation'. Therefore option 2 is correct. 

Important Points

• To reduce reverberation, the roof and walls of the auditorium are generally covered with sound-absorbent materials like compressed fibreboard, rough plaster, or draperies.
• The seat materials are also selected based on their sound-absorbing properties.

Additional Information

• If we shout or clap near a suitable reflecting object such as a tall building or a mountain, we will hear the same sound again a little later. This sound which we hear is called an echo.