Two tubes closed at one end and vibrating in their fundamental modes produce 2 beats per second. If both ends of these same tubes are opened, the number of beats produced per second when they vibrate in their fundamental modes is:

Consider the following statements regarding waves: 1. If the particles of a medium move along the direction of propagation of the wave, the wave is called a longitudinal wave. 2. If the particles of a medium vibrate perpendicular to the direction of propagation of the wave, the wave is called a transverse wave. 3. Transverse waves involve changes in the shape/shear of the medium, whereas longitudinal waves involve changes in the density/volume of the medium. Which of the statements given above are correct?

At what speed should a source of sound move away from a stationary observer so that the observer perceives the apparent frequency to be half of the original frequency? (where v is the speed of sound)