Vapor Pressure. The Macroscopic View. The vapor pressure of a liquid is the equilibrium pressure of a vapor above its liquid (or solid); that is, the pressure of the vapor resulting from evaporation of a liquid (or solid) above a sample of the liquid (or solid) in a closed container.
Transverse and longitudinal are two different types of waves. The main difference between transverse and longitudinal waves is that in transverse waves, oscillations occur perpendicular to the direction of propagation of the wave, whereas in longitudinal waves, oscillations occur parallel to the direction of propagation of the wave.
While all electromagnetic waves are transverse, mechanical waves can be transverse or longitudinal, which brings us to our next type of wave. Longitudinal Waves. In a longitudinal wave, the particles of the medium move parallel to the wave's direction of travel.