Question

If fundamental frequency of an open pipe is 0. Its fundamental frequency when it is half-filled with water is

Answer 1

Here is the answer to your question

 

For open end pipe in air, fundamental frequency:

f = V/2L

For the pipe closed at one end (dipped in water), fundamental frequency:

f' = V/4L'

L' = L/2

f' = V/2L = f