1. Name of
Region
Wavelength
Range (in m, μm,
and nm)
Frequency Range
Technological
Applications /
Role in Nature
Gamma
Rays
10-14 to 10-10 m
10-8 to 10-4 μm
10-5 to 10-1 nm
3x1022 to 3x1018 Hz Radiation therapy
X - Rays
10-14 to 10-8 m
10-8 to 10-2 μm
10-5 to 10 nm
3x1022 to 3x1016 Hz
Radiation therapy;
diagnosis (lower
frequencies)
Ultraviolet
Rays
10-8 to 4x10-7 m
10-2 to 0.4 μm
10-5 to 400 nm
3x1016 to 0.75x1016 Hz
Tanning;
Promotes production of
Vitamin D in human skin;
photosynthesis in plants
Visible
Light
4x10-7 to 8x10-7 m
0.4 to 0.8 μm
400 to 800 nm
0.75x1016 to 0.375x1016 Hz
Lamps for seeing
(Eyes respond to this
range)
Infrared
8x10-7 to 10-3 m
0.8 to 103μm
800 to 106 nm
0.375x1016 to 3x1011 Hz Infrared photography
Radio
Waves
10-4 to 106 m 3x1012 to 300 Hz Communication devices
Table 1: Regions of the entire electromagnetic spectrum and general applications.
 In order of decreasing frequency (and increasing wavelength), the
various regions of the electromagnetic spectrum are:
gamma rays , x-rays ,ultraviolet , visible light , infrared
, microwaves , and radio waves .
 Electromagnetic energy from the sun consists mostly of a small
amount of ultraviolet, all visible light, and some infrared.

2.  Light is a particular type of electromagnetic radiation that can be
seen and sensed by the human eye, but this energy exists at a wide
range of wavelengths.
 The micron is the basic unit for measuring the wavelength of
electromagnetic waves.
 The spectrum of waves is divided into sections based on
wavelength. The shortest waves are gamma rays, which have
wavelengths of 10e-6 microns or less. The longest waves are radio
waves, which have wavelengths of many kilometers.
 The range of visible consists of the narrow portion of the spectrum,
from 0.4 microns (blue) to 0.7 microns (red).