posted by alejandra .
what are the units of wavelengh
They can be any length units, but it is common to use meters for radio waves, centimeters for microwaves, micrometers for infrared, and nanometers or Angstroms (10^-8 cm) for visible and ultraviolet light.
Regardless of what I wrote in my previous answer, if you are performing a calculation using a formula that involves wavelength, it is a usually good idea to express wavelengths in meters in all situations. That is the official SI unit for length.