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
Solution
A closed pipe of length ℓ1=1.5m resonates in its fundamental mode at fc=4ℓ1v; an open pipe of length ℓ2=3.5m resonates at fo=2ℓ2v. The beat frequency is
∣fc−fo∣=6v−7v=42v=7.
Solving, v=294m/s.
JEE Main · 2024 · 27 Jan 2024 · Shift 2 · Integer answer