STANDARDPhysics-Waves
STANDARD Physics Sound Waves in Pipes MCQ Question
Type: MCQ-numerical-Medium-Class 11
A pipe 17 cm long is closed at one end. Which harmonic mode of the pipe resonates a 1.5 kHz source? (Speed of sound in air = 340 m s⁻¹)
A
First
B
Third
C
Fifth
D
Seventh
Correct Answer
Option B
Detailed Explanation
In a closed pipe (open at one end), the frequency of its nth harmonic is given by vₙ = nv/4L, where n = 1, 3, 5, 7, .... For the nth harmonic to resonate with a 1.5 kHz source, we solve 1.5 x 10³ = nv/4L. Substituting the values, we find n = 3, which corresponds to the third harmonic.
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