A tuning fork with a frequency of \(800\) Hz produces resonance in a resonance column tube with the upper end open and the lower end closed by the water surface. Successive resonances are observed at lengths of \(9.75\) cm, \(31.25\) cm, and \(52.75\) cm. The speed of the sound in the air is:

1.	\(500\) m/s	2.	\(156\) m/s
3.	\(344\) m/s	4.	\(172\) m/s

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. $\frac{({\rho }_A+{\rho }_0)}{({\rho }_A-{\rho }_0)}$

2. $\frac{({\rho }_A+2{\rho }_0)}{({\rho }_A-2{\rho }_0)}$

3. $\frac{{\rho }_A}{{\rho }_A}$

4. $\frac{\left({\rho }_A+\frac{1}{2}{\rho }_0\right)}{\left({\rho }_A-\frac{1}{2}{\rho }_0\right)}$

Two wires, \(A\) and \(B,\) of a musical instrument 'Sitar' produce \(3\) beats per second. If the tension of \(B\) is raised, the number of beats becomes \(1\) beat per second. If the frequency of \(A\) is \(450~\text{Hz}\), then the original frequency of \(B\) will be:
1. \(447~\text{Hz}\)
2. \(453~\text{Hz}\)
3. \(449~\text{Hz}\)
4. \(451~\text{Hz}\)

The fundamental frequency of an open organ pipe is \(200~\text{Hz}.\) When the half-length of the pipe is immersed in water, the fundamental frequency of the air column in the pipe will be:
1. \(100~\text{Hz}\)
2. \(200~\text{Hz}\)
3. \(400~\text{Hz}\)
4. \(800~\text{Hz}\)

What is sound level for intensity of 10^–6 W/m²?

1. 50 dB 

2. 60 dB

3. 70 dB 

4. 80 dB

A vibrating tuning fork of frequency \(1000~\text{Hz}\) is placed near the open end of a long cylindrical tube. The tube has a side opening and is also fitted with a movable reflecting piston. As the piston is moved through \(x\) distance, the intensity of sound changes from a maximum to a minimum for an observer at the side opening. If the speed of sound is \(350\) meters per second, then \(x\) is:

1. \(35~\text{cm}\)
2. \(17.5~\text{cm}\)
3. \(8.75~\text{cm}\)
4. \(10~\text{cm}\)

A : The propagation of sound in air should be an isothermal process.

R : As air is bad conductor of heat, its temperature does not change by compression or expansion.

Given below are two statements:

Which one of the following statements is true?