ध्वनि के बार-बार परावर्तन के कारण उत्पन्न होने वाली बहु-प्रतिध्वनियों (multiple echoes) की परिघटना को ___________ कहा जाता है।

A closed organ pipe and an open organ pipe are tuned to the same fundamental frequency. The ratio of their lengths is:

At what speed should a source of sound move away from a stationary observer so that the observer finds the apparent frequency equal to half of the original frequency? (where v is the velocity of sound)