Question 47. A closed organ pipe 150 cm long gives 7 beats per second with an open organ pipe of length 350 cm , both vibrating in fundamental mode. The velocity of sound is ____ m / s.
Answer (294.00)
Explanation:
f_c = \frac{v}{4 \ell_1} \quad f_o = \frac{v}{2 \ell_2} \left|f_{c}-f_{0}\right|=7 \frac{v}{4 \times 150}-\frac{v}{2 \times 350}=7 \frac{v}{600 ~cm}-\frac{v}{700 ~cm}=7 \frac{v}{6 ~m}-\frac{v}{7 ~m}=7 v\left(\frac{1}{42}\right)=7 v=42 \times 7