Question

State the characteristics of progressive waves.

Answer 1

Progressive wave

A progressive wave is defined as the onward transmission of the vibratory motion of a body in an elastic medium from one particle to the successive particle.

Characteristics of a progressive wave:

• Each particle in a medium executes the same type of vibration. Particles vibrate about their mean positions performing the simple harmonic motion.
• All vibrating particles of the medium have the same amplitude, period, and frequency but the phase, (i.e., state of vibration of a particle), changes from one particle to another.
• No particle remains permanently at rest. Each particle comes to rest momentarily while at the extreme positions of vibration.
• The particles attain maximum velocity when they pass through their mean positions.
• During the propagation of wave, energy is transferred along with 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.
• Wave motion is doubly periodic, that is, it is regular in both time and space.
• 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 and produce crests and troughs in their medium of travel. In longitudinal waves, vibrations of particles produce compressions and rarefactions along the direction of propagation of the wave.
• Both, the transverse as well as longitudinal, mechanical waves can propagate through solids but only longitudinal waves can propagate through fluids.