A glass tube of 1 m length is filled with water. The water can be drained out slowly from the bottom of the tube. If vibrating tuning fork of frequency 500 Hz is brought at the upper end of the tube then total number of resonances obtained are [Velocity of sound in air is 320 ms⁻¹ ] (a) 3 (b) 4 (c) 1 (d) 2

Answer: (a). λ = (320)/(500) = 0.64 m, so (λ)/(4) = 0.16 m. Resonating lengths: ((2k-1)λ)/(4) = 0.16, 0.48, 0.80, 1.12 m... Only lengths up to 1 m are possible: 0.16, 0.48, 0.80 m, i.e. 3 resonances. So the answer is (a) 3.

A glass tube of 1 m length is filled with water. The water can be… | MHT CET 2021 (22 Sep, Shift 2)

Q88MHT CET 2021 · 22 SEP · SHIFT 2Medium

Organ Pipes & Resonance Tube

A glass tube of $1\text{ m}$ length is filled with water. The water can be drained out slowly from the bottom of the tube. If vibrating tuning fork of frequency $500\text{ Hz}$ is brought at the upper end of the tube then total number of resonances obtained are [Velocity of sound in air is $320\text{ ms}^{-1}$ ]

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Answer: (a)

$\lambda = \frac{320}{500} = 0.64$ m, so $\frac{\lambda}{4} = 0.16$ m.
Resonating lengths: $\frac{(2k-1)\lambda}{4} = 0.16, 0.48, 0.80, 1.12$ m...
Only lengths up to 1 m are possible: 0.16, 0.48, 0.80 m, i.e. 3 resonances.
So the answer is (a) 3.

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Organ Pipes & Resonance Tube question from MHT CET 2021 (22 Sep, Shift 2)

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