This is the process of matter changing from the liquid to the solid state?

The process is called freezing.

Explanation:

The process in which matter changing from the liquid to the solid state is called Freezing. Generally the freezing point of liquid like  water is 32°F or 0°C. Freezing is just the opposite of melting in which a solid melted to liquid. different liquid has different freezing point. the freezing point of liquid nitrogen at a pressure of one atmosphere is -345.8°F.

when the displaced particles are perpendicular to the direction the wave travels, is called a transverse wave, whereas in longitudinal wave the displace practices are parallel to the direction of the wave.

in the given image:

first image shows - longitudinal wave

second image shows - transverse wave

third image shows - longitudinal wave

fourth image shows - longitudinal wave