Question

If the temperature of air in an organ pipe increases, what happens to the resonance frequencies ?

• A. Remains same
• B. Decreases
• C. Increases
• D. Depends on density of air

Answer 1

The correct option is C Increases

Speed of sound $v=\sqrt{\frac{\gamma RT}{M}}$

Resonance frequencies
$f=\frac{nv}{2l}$, where n is an integer.
i.e $f\propto \sqrt{T}$
Therefore, resonant frequencies increase with temperature.