Gases can be compressed, because they just take up the space surrounding them. The attractive forces between the particles in a gas are very weak, so the particles are free to move in random direction. They just move along until they collide, either with the walls of the container or with each other. Moreover, gases can be compressed because the particles are far apart and they have space to move into.
Wavelength= speed / frequency
so.....3× 10^8 / 7.26×10^14
= .413× 10^(-6)
in scientific notation= 4.13×10^(-7)
in nanometer = 413 nm
