Question

A student is experimenting with resonance tube apparatus in Physics lab to find the speed of sound at room temperature. He got resonating lengths of air column as 17 cm and 51 cm, using tuning fork of frequency 512 Hz. Find speed of sound at room temperature and specify, whether the side water reservoir was moved upward or downward to obtain the second resonance (51 cm)?

• A. 348 m/s, downwards
• B. 348 m/s, upwards
• C. 332 m/s, downwards
• D. 332 m/s, upwards

Answer 1

The correct option is A 348 m/s, downwards

For resonance in a resonance tube,

$f_1=\frac{v}{4l_1}$

$f_2=\frac{3v}{4l_2}$

$f_1=f_2=512Hz$

Thus $v=4\times f_1\times l_1=4\times 512\times 0.17m/s=348m/s$