Read the following case and answer the following question:
A group of students visited a science centre where they observed an underwater SONAR demonstration. The instructor explained that SONAR sends ultrasonic sound waves towards an underwater object. The waves are reflected from the object and return to the SONAR device. The time taken for the reflected waves to return is measured to determine the distance of the object.
The instructor then demonstrated the difference between an echo and reverberation. In an open area near a large wall, a student produced a short sound and heard a distinct repetition after a delay. Inside an auditorium with hard walls, floor and ceiling, the students noticed that sound continued briefly and became less clear because of multiple reflections. The instructor explained that this effect is called reverberation.
The auditorium had curtains and carpets on some surfaces. These materials helped to absorb some of the sound energy and reduce excessive reflections, making speech clearer.
The instructor then demonstrated the difference between an echo and reverberation. In an open area near a large wall, a student produced a short sound and heard a distinct repetition after a delay. Inside an auditorium with hard walls, floor and ceiling, the students noticed that sound continued briefly and became less clear because of multiple reflections. The instructor explained that this effect is called reverberation.
The auditorium had curtains and carpets on some surfaces. These materials helped to absorb some of the sound energy and reduce excessive reflections, making speech clearer.
1. Which statement correctly distinguishes the echo observed near the wall from the reverberation in the auditorium?
2. The SONAR device sends a pulse towards an underwater object and receives the reflected pulse after \(1.2\ s\). If the speed of sound in water is \(1500\ m/s\), what is the distance of the object from the SONAR device?