Question

The resonant frequencies of a tube closed at one end are 400 hz apart. if both ends of the tube are then opened, the new 1st harmonic frequency is?

Answer 1

The new first harmonic frequency of a tube closed at one end, when both ends are opened, is half the original frequency.

Step-by-step explanation:

When a tube is closed at one end, the resonant frequencies are determined by the length of the tube. The first harmonic or fundamental frequency of a tube closed at one end is given by:

f1 = v/4L

Where f1 is the fundamental frequency, v is the speed of sound, and L is the length of the tube. If both ends of the tube are opened, the fundamental frequency will double. Therefore, the new first harmonic frequency will be:

f1' = 2(f1) = 2(v/4L) = v/2L

So, the new first harmonic frequency will be half the original frequency of the closed tube.