Define progressive wave and what are the characteristics of progressive waves

A wave in which the disturbance produced in the medium travels in a given direction continuously without any damping and obstruction from one particle to another is a progressive wave or it is also called as travelling wave 

The characteristics of progressive waves are as follows, ✈

✈ Each particle in a medium executes the same type of vibration. Particles vibrate about their mean positions performing simple harmonic motion(SHM)

✈All vibrating particles of the medium have the same amplitude, period & frequency.

✈ No particle remains permanently at rest. Each particle comes to rest momentarily while at the extreme positions of vibration.

✈ The phase (state of vibration of a particle), changes from one particle to the next particle.

✈The particles attain maximum velocity when they pass through their mean positions.

✈During the propagation of wave, energy is transferred along the wave. There is no transfer

of matter.

✈The wave propagates through the medium with a certain velocity. This velocity depends upon the properties of the medium.

✈Progressive waves are of two types -transverse waves and longitudinal waves.

✈In a transverse wave, vibrations of particles are perpendicular to the direction of propagation of the wave. In a transverse wave alternate crests and troughs are produced in their medium . Whereas in a longitudinal wave, vibrations of particles is parallel to the direction of the propagation of the wave. Also in longitudinal waves alternate compressions and rarefactions are formed along the direction of propagation of the wave.

✈The transverse waves can travel through solids and on liquid surface whereas the longitudinal wave can travel through solid liquid and gas medium.