SNC2D – Physics: Optics
Electromagnetic Waves in our Society
(p. 466, Science Perspectives 10, Nelson)
Red
Violet
Electromagnetic waves travel at the speed of light (c = 3.0 ×108 m/s in a vacuum) and do not
require a medium for transmission.
Type of
electromagnetic wave
Radio
Use/phenomena
Wavelength Range
AM/FM, tv signals, cellphones, Radar,
astronomy
> 1 cm long
Infrared
Remote controls, heat detection, physical
therapy (heating)
700 nm – 0.05 cm
Visible
Range of human vision
400 – 700 nm
Ultraviolet
Causes skin to tan/burn and increases skin
cancer risk, kills bacteria (sterilization)
10 – 400 nm
X-rays and gamma rays
Medical imaging, cancer treatment, security
equipment
< 10 nm
In optics, we are often dealing with numbers that are very small (e.g. the wavelength of gamma
rays is less than 0.01 nm = 1.0 × 1011 m) or very large (the speed of light c = 3.0 ×108 m/s in a
vacuum), so we often need to use scientific notation and to do unit conversions.
SNC2D – Physics: Optics
Electromagnetic Waves in our Society
(p. 466, Science Perspectives 10, Nelson)
Red
Violet
Electromagnetic waves travel at the speed of light (c = 3.0 ×108 m/s in a vacuum) and do not
require a medium for transmission.
Type of
electromagnetic wave
Radio
Use/phenomena
Wavelength Range
Infrared
Visible
Ultraviolet
X-rays and gamma rays
In optics, we are often dealing with numbers that are very small (e.g. the wavelength of gamma
rays is less than 0.01 nm = 1.0 × 1011 m) or very large (the speed of light c = 3.0 ×108 m/s in a
vacuum), so we often need to use scientific notation and to do unit conversions.