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 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 \(20^{\circ}\text{C}\) (which is \(343\) m/s)?
1. \(4.3\times10^3\) N
2. \(3.2\times10^4\) N
3. \(2.06\times10^4\) N
4. \(1.2\times10^4\) 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 \(450~\text{Hz}\), then the original frequency of \(B\) will be:
1. \(447~\text{Hz}\)
2. \(453~\text{Hz}\)
3. \(449~\text{Hz}\)
4. \(451~\text{Hz}\)