Arrange the following electromagnetic waves in order of increasing frequency: $$\gamma-rays$$, microwaves, infrared rays and ultraviolet rays.
Electromagnetic radiation is classified into types according to the frequency of the wave. These types include, in order of increasing frequency, radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays.
The frequency is the inverse of wavelength.
Hence, in the order of increasing frequency, the waves are $$Microwave < Infrared < Ultraviolet < \gamma-rays$$.