A cylindrical tube, open at both ends, has a fundamental frequency f0 in air. The tube is dipped vertically into water such that half of its length is inside water. The fundamental frequency of the air column now is

(1) 3 f0/4

(2) f0

(3) f0/2

(4) 2 f0

Concept Questions :-

Standing waves
High Yielding Test Series + Question Bank - NEET 2020

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If the length of a closed organ pipe is 1.5 m and the velocity of sound is 330 m/s, then the frequency for the second note is

(1) 220 Hz

(2) 165 Hz

(3) 110 Hz

(4) 55 Hz

Concept Questions :-

Standing waves
High Yielding Test Series + Question Bank - NEET 2020

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A pipe 30 cm long is open at both ends. Which harmonic mode of the pipe is resonantly excited by a 1.1 kHz source? (Take the speed of sound in air = 330 ms–1

(1) First

(2) Second

(3) Third

(4) Fourth

Concept Questions :-

Standing waves
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A source of sound placed at the open end of a resonance column sends an acoustic wave of pressure amplitude ${\rho }_{0}$ inside the tube. If the atmospheric pressure is ${\rho }_{A}$ , then the ratio of maximum and minimum pressure at the closed end of the tube will be :

1. $\frac{\left({\rho }_{A}+{\rho }_{0}\right)}{\left({\rho }_{A}-{\rho }_{0}\right)}$

2. $\frac{\left({\rho }_{A}+2{\rho }_{0}\right)}{\left({\rho }_{A}-2{\rho }_{0}\right)}$

3. $\frac{{\rho }_{A}}{{\rho }_{A}}$

4. $\frac{\left({\rho }_{A}+\frac{1}{2}{\rho }_{0}\right)}{\left({\rho }_{A}-\frac{1}{2}{\rho }_{0}\right)}$

Concept Questions :-

Standing waves
High Yielding Test Series + Question Bank - NEET 2020

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Two closed pipe produce 10 beats per second when emitting their fundamental nodes. If their length are in ratio of 25 : 26. Then their fundamental frequency in Hz, are :

(1) 270, 280

(2) 260, 270

(3) 260, 250

(4) 260, 280

Concept Questions :-

Standing waves
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

If v is the speed of sound in the air then the shortest length of the closed pipe which resonates to a frequency n :

(1) $\frac{v}{4n}$

(2) $\frac{v}{2n}$

(3) $\frac{2n}{v}$

(4) $\frac{4n}{v}$

Concept Questions :-

Standing waves
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The frequency of fundamental tone in an open organ pipe of length 0.48 m is 320 Hz. The speed of sound is 320 m/sec. Frequency of fundamental tone in closed organ pipe will be :

(1) 153.8 Hz

(2) 160.0 Hz

(3) 320.0 Hz

(4) 143.2 Hz

Concept Questions :-

Standing waves
High Yielding Test Series + Question Bank - NEET 2020

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What is the minimum length of a tube, open at both ends, that resonates with tuning fork of frequency 350 Hz? [velocity of sound in air = 350 m/s]

(1) 50 cm

(2) 100 cm

(3) 75 cm

(4) 25 cm

Concept Questions :-

Standing waves
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The harmonics which are present in a pipe open at one end are :

(1) Odd harmonics

(2) Even harmonics

(3) Even as well as odd harmonics

(4) None of these

Concept Questions :-

Doppler effect
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The stationary wave $y=2a\mathrm{sin}kx\mathrm{cos}\omega \text{\hspace{0.17em}}t$ in a closed organ pipe is the result of the superposition of $y=a\mathrm{sin}\left(\omega \text{\hspace{0.17em}}t-kx\right)$ and

(1) $y=-a\mathrm{cos}\left(\omega \text{\hspace{0.17em}}t+kx\right)$

(2) $y=-a\mathrm{sin}\left(\omega \text{\hspace{0.17em}}t+kx\right)$

(3) $y=a\mathrm{sin}\left(\omega \text{\hspace{0.17em}}t+kx\right)$

(4) $y=a\mathrm{cos}\left(\omega \text{\hspace{0.17em}}t+kx\right)$

Concept Questions :-

Standing waves