Which one of the following statements is not true for a flute, a musical instrument?

Explanation:

Momentum of waves on the blowing jet determines the loudness of the produced note:

• The loudness of a note produced by a flute is affected by the way the player blows across the mouthpiece, including the speed and angle of the airstream, so this statement is somewhat true.

Arrival time of the waves on the blowing jet determines the pitch of the produced note:

• The pitch of the note is determined mainly by the length of the vibrating column of air, which can be altered by opening or closing the holes on the flute's body. The interaction between the blowing jet and the edge of the embouchure hole can also affect the pitch, but the arrival time of the waves on the blowing jet does not determine the pitch. Therefore, this statement is not true.

Sound comes from a vibrating column of air inside the flute:

• This statement is true. The flute produces sound by setting up vibrations in a column of air inside its body.

Sound comes from a vibrating column of air inside as well as outside the flute: 

• Sound produced is due to air column present inside a flute, outside it only propagates. 
• The primary source of sound in a flute comes from the vibrating column of air inside the instrument itself. While there may be some interaction with the surrounding air, it's not generally considered that the sound comes from a vibrating column of air both inside and outside the flute.

• So, the correct statement that is not true is: Sound comes from a vibrating column of air inside as well as outside the flute.