Electromagnetic Spectrum Chapter Notes | Physics for GCSE/IGCSE - Year 11 PDF Download

 Page 1


Spectra
? Dispersion of light
? The phenomenon of splitting up of a white light into its constituent colours
? E.g. rainbow
? The cause of dispersion of light is that white light consists of 7 different colours
? Electromagnetic waves can all be reflected, refracted and diffracted
? Wavelength decreases ------->
? Frequency increases --------->
? Energy increases -------->
Uses of electromagnetic waves
? Radio waves
? Detected by aerials
? Used for communication (broadcast radio and television signals)
? Microwaves
? Detected by aerials (diodes)
? Communication (satellite television broadcasting)
? Cooking
? Used to transmit mobile phone signals between masts
? Infrared
? Emitted by hot objects
? Detected by skin/ thermometer/ photographic film
? Used for seeing
? Ultraviolet radiation
? Emitted by hot objects
? Detected by skin, photographic film
? Used for sun tanning
? Energy efficient lamps
? Phototherapy
? Killing bacteria (water disinfection)
? Creating fluorescent effects
? Equipment disinfection (food, beverage, air)
Page 2


Spectra
? Dispersion of light
? The phenomenon of splitting up of a white light into its constituent colours
? E.g. rainbow
? The cause of dispersion of light is that white light consists of 7 different colours
? Electromagnetic waves can all be reflected, refracted and diffracted
? Wavelength decreases ------->
? Frequency increases --------->
? Energy increases -------->
Uses of electromagnetic waves
? Radio waves
? Detected by aerials
? Used for communication (broadcast radio and television signals)
? Microwaves
? Detected by aerials (diodes)
? Communication (satellite television broadcasting)
? Cooking
? Used to transmit mobile phone signals between masts
? Infrared
? Emitted by hot objects
? Detected by skin/ thermometer/ photographic film
? Used for seeing
? Ultraviolet radiation
? Emitted by hot objects
? Detected by skin, photographic film
? Used for sun tanning
? Energy efficient lamps
? Phototherapy
? Killing bacteria (water disinfection)
? Creating fluorescent effects
? Equipment disinfection (food, beverage, air)
? Gamma ray
? Emitted by nuclei
? Detected by photographic film, geiger-muller tubes
? Used for treating cancer
? Detecting faults in metals and concrete
? Sterilising equipment or killing bacteria in food
? Can damage or mutate human cells, which can lead to cancer
? X-ray
? Emitted by atoms
? Detected by photographic film
? Used for x-ray photographs in medicine
? Detecting faults in metals and concrete
? Can damage human cells
? Electromagnetic hazards
? Overexposure to certain types of electromagnetic radiation can be harmful
? Higher the frequency of the radiation, the more damage it is likely to cause to the body
? Microwaves can cause internal heating of body tissues
? Infrared radiation is felt as heat and cause skin to burn
? X-rays damage cells causing mutation and cell death. May lead to cancer
? Gamma rays also damage cells causing mutation and cell death