Answer
Ultraviolet
Step-by-step explanation
The types of radiation and their wavelength are:
Gamma < 10⁻¹² m
X-rays 1 nm - 1 pm
Ultraviolet 400 nm - 1 nm
Visible 750 nm - 400 nm
Near-infrared 2.5 μm - 750 nm
Infrared 25 μm - 2.5 μm
Microwaves 1 mm - 25 μm
Radio waves > 1 mm
Hence, the given wavelength of 2.86 X 10⁻⁸ m corresponds to Ultraviolet.