Question

An empty vessel is partially filled with water, then the frequency of vibration of air column in the vessel

• A. Remains same
• B. Decreases
• C. Increases
• D. First increases then decreases

Answer 1

Answer: (C)

Increases

Answer 2

For closed pipe in general $n = \frac{v}{4l}(2N - 1)$ ⇒ $n \propto \frac{1}{l}$

i.e. if length of air column decreases frequency increases.