Q.
Air is blown at the mouth of a tube of length 25 cm and diameter equal to 2 cm open at both ends. If velocity of sound in air in $330ms^{- 1}$, the sound emitted will have all the frequency in the group
A) 330,990,1690 Hz
B) 302,664,1320 Hz
C) 660,1320,1980 Hz
D) 660,100,3300 Hz
Explanation
(c) Fundamental frequency
$n = \frac{v}{2l} = \frac{330}{2 \times 0.25} = 660\ Hz$
Frequency of overtones are $2n,3n,4n,\ldots. = 1320,1980,2640\ Hz$.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.