Oscillation Waves

A pipe open at both ends has a fundamental frequency f in air. The pipe is dipped vertically in water so that half of it is in water. The fundamental frequency of the air column is now:

  1. 3f/4
  2. 2f
  3. f
  4. f/2

Solution

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

The correct option is C.