greater amount of energy carried by the EM wave
speed of light = wavelength / period
speed of light = frequency x wavelength
electron gain energy and escapes from the atoms
damage genes and DNA
lowest frequency and longest wavelength
used for radio and TV broadcasting
heat up food due to friction and collision between rotating water molecule.
lowest frequency radio waves are reflected from an electrically charged layer of the upper atmosphere, called ionosphere
can reach receivers not in sight due to curvature of earth surface. eg. remote control cars and walkie talkie
refer to radio waves with short wavelengths
transmit great quantities of data due to higher frequencies.
repeater are used to receive, convert and transmit information over large distances.
eg. Microwave oven, satelite, radar and mobile phones
causes molecules to resonate and vibrate
sun emits half of its radiation thru infrared and light bulbs emit infrared more than light.
eg. remote controls, night vision goggles, thermal imaging to detect virus such as SARS and H1N1
only range of frequencies visible to human eye produced by luminous objects
red light at low frequencies and violet light at high frequencies
colour of light is dependent on frequencies and wavelength
eg. optical fibres, light photography, endoscopy
from the sun
stimulate production of melanin, kills bacteria and creates ultraviolet watermark on banknotes
high frequencies and high penetrating capabilities thru objects
high frequency and energy
eg. X ray medical imaging, airport security imaging
highest frequency and penetrating
emitted from radioactive decay of unstable atoms and isotopes
kill cancerous cells but also healthy cells
medical tools are sterilized with gamma rays