A vibrating tuning fork of frequency 1000 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 cm

2. 17.5 cm

3. 8.75 cm

4. 10 cm

 In a guitar, two strings \(A\) and \(B\) made of same material are slightly out of tune and produce beats of frequency \(6~\text{Hz}\). When tension in \(B\) is slightly decreased, the beat frequency increases to \(7~\text{Hz}\).  If the frequency of \(A\) is \(530~\text{Hz}\), the original frequency of \(B\) will be:

A string with a mass \(2.50~\text{kg}\) is under a tension of \(200~\text{N}\). The length of the stretched string is \(20.0~\text{m}\). If the transverse jerk is struck at one end of the string, how long does it take for the disturbance to reach the other end?
1. \(0.5~\text{s}\)
2. \(0.6~\text{s}\)
3. \(0.4~\text{s}\)
4. \(0.1~\text{s}\)

A stone dropped from the top of a tower of height \(300\) m splashes into the water of a pond near the base of the tower. When is the splash heard at the top?
(Given that the speed of sound in air is \(340\) m/s and \(g=9.8\) m/s²)
1. \(7.7\)
2. \(8.7\)
3. \(6.7\)
4. \(7.8\)

A steel wire has a length of 12.0 m and a mass of 2.10 kg. What should be the tension in the wire so that the speed of a transverse wave on the wire equals the speed of sound in dry air at \(20^{\circ}\mathrm{C}\) (which is  343 m/sec)?
1. $4.3\times {10}^3$ N
2. $3.2\times {10}^4$ N
3. $2.06\times {10}^4$ N
4. $1.2\times {10}^4$ N
 

The speed of sound in air is:

A bat emits an ultrasonic sound of frequency 1000 kHz in the air. If the sound meets a water surface, what is the wavelength of the reflected sound? (The speed of sound in air is 340 m/sec and in water is 1486 m/sec)
1. \(3.4 \times 10^{-4}~\text{m}\)
2. \(1 . 49 \times 10^{- 3}  ~ \text{m}\)
3. \(2 . 34 \times 10^{- 2}   ~\text{m}\)
4. \(1 . 73 \times10^{- 3}   ~\text{m}\)

The fundamental frequency of an open organ pipe is \(200\) 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. \(100\) Hz
2. \(200\) Hz
3. \(400\) Hz
4. \(800\) Hz

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 Hz, then the original frequency of B will be:

1. 447 Hz

2. 453 Hz

3. 449 Hz

4. 451 Hz
 

A bat emits an ultrasonic sound of frequency \(1000~\text{kHz}\) in the air. If the sound meets a water surface, what is the wavelength of the refracted sound?
(speed of sound in air is \(340~\mathrm{m/s}\) and in water \(1486~\mathrm{m/s}\))