JEE Main 2024 Physics question
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
Closed pipe: n₁ = v/(4L₁) = v/6; open pipe: n₂ = v/(2L₂) = v/7. Then n₁ − n₂ = 7 gives v(1/6 − 1/7) = 7, so v = 294 m/s.