SSC MTS EXAM

Detailed explanation-1: -The open end of the tube is always an antinode since the air molecules can vibrate horizontally parallel to the length of the tube. Figure 3: Displacement of air molecules represented as a standing sound wave in an closed tube. For closed tubes, we can have only odd-numbered harmonics.

Detailed explanation-2: -A compression is created, which propagates back down the air column away from the open end. You may have noticed from this explanation that when a sound wave reaches the open end of a tube, not only is it reflected but it is also inverted. A rarefaction in the incident wave becomes a compression in the reflected wave.

Detailed explanation-3: -Tubes with two open ends The longest standing wave in a tube of length L with two open ends has displacement antinodes (pressure nodes) at both ends. It is called the fundamental or first harmonic. The next longest standing wave in a tube of length L with two open ends is the second harmonic.

Detailed explanation-4: -At the antinodes, strain is minimum. At the nodes strain is maximum. So variation of pressure is maximum at the nodes. Hence a loud sound is heard at the node.