How do EM waves differ from mechanical waves?
The Electromagnetic Spectrum
Microwave: Low frequency and long wavelength but not as low and long as radio. Used for cooking and transmitting signals such as mobile phone calls.
Infrared: Low frequency and long wavelength but not as low and long as microwave and radio. Wavelength: Ranges from 710nm- 1mm. Used in optical fibre communication.
Visible: Medium frequency and wavelength. Wavelength: 400-700nm. Used for seeing.
Ultraviolet: High frequency and short wavelength but not as high and short as X-ray and Gamma-Ray. Wavelength: 10-310nm. Used for detecting forged bank notes by florescence and security pens. It is found naturally in sunlight.
X-Ray: High frequency and short wavelength but not as high and short as Gamma-Ray. Wavelength: 0.01-10nm. Used for finding medical images of bones and also in industry to check metal components and welds for cracks or other damage.
Gamma-Ray: Highest frequency and shortest wavelength. Wavelength: Less than 0.01nm (size of an atomic nucleus). Used for killing cancer cells and harmful bacteria in food.