Question

A resonance air column of length 20 cm resonates with a tuning fork of frequency

250 Hz. The speed of sound in air is

[AFMC 1999; BHU 2000; CPMT 2001]

• A. 300 m/s
• B. 200 m/s
• C. 150 m/s
• D. 75 m/s

Answer 1

The correct option is B

200 m/s

For closed pipe $n_1=\frac{v}{4l}\Rightarrow 250=\frac{v}{4\times 0.2}\Rightarrow v=200m/s$