Explain oscillation in air column of close organ pipe.

1.	Explain oscillation in air column of close organ pipe.
Answer» If the air is blown lightly at the open end of the closed organ pipe, then the air column vibrates (as shown in figure) in the fundamental mode. There is a node at the closed end and an antinode at the open end. If l is the length of the tube,l = λ1/4 or λ1 = 4l …... (1)If n1 is the fundamental frequency of the vibrations and v is the velocity of sound in air, thenn1 = v/λ1 = v/4l …... (2)If air is blown strongly at the open end, frequencies higher than fundamental frequency can be produced. They are called overtones. Fig.b & Fig.c shows the mode of vibration with two or more nodes and antinodes.

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