Question

An organ pipe with both ends open has a length L=25cm .An extra hole is created at position (L/2) .The lowest frequency of sound produced is
(Assume speed of sound =340m/s)

Answer 1

Antinodes are formed at the open ends. Thus, antinode forms at L/2:

$$\lambda=25\text{ cm},\\\space\\ f=\frac{v}{\lambda}=\frac{340}{0.25}=1360\text{ Hz}.$$