em spectrum (physics) Flashcards
what are electromagnetic waves
- made up of oscillating electric and magnetic fields
- all electromagnetic waves are transverse waves –> electric and magnetic fields oscillate perpendicularly to the direction of propagation of the electromagnetic wave
do electromagnetic waves carry electric charges
no
can electromagnetic waves travel without a medium
yes
do em waves transfer energy
yes
do em waves undergo reflections and refractions
yes
arrange the em waves in decreasing wavelength
radio waves
microwaves
infrared
visible light
ultraviolet
x-rays
gamma rays
arrange the em waves in decreasing frequency
gamma rays
x-rays
ultraviolet
visible light
infrared
microwave
radio waves
arrange the em waves in increasing wavelength
gamma rays
x-rays
ultraviolet
visible light
infrared
microwave
radio waves
arrange the em waves in increasing frequency
radio waves
microwaves
infrared
visible light
ultraviolet
x-rays
gamma rays
uses of radio waves
- television and radio communication
- radio telescopes for radio astronomy to srudy radio frequencies from outer space
- Radio Frequency Identification (RFID) tag for tagging library books, items in warehouses, merchandise
uses of microwaves
- microwave oven
- Wi-fi signals
- satellite communication
disadv of microwaves
- heating effect (temp increases)
uses of infrared radiation
- remote control
- intruder alarm
- thermal imaging (infrared camera)
uses of visible light
- photography
- optical fibres in medicine and telecommunications
- LASER in medicine or engineering
disadv of infrared radiation
heating effect (temp increases)
uses of ultraviolet radiation
- sterilisation of medical equipment
- disinfection of water in water treatment plants
- check for counterfeit bank notes
disadv of ultraviolet radiation
- prolonged exposure can lead to sunburns, premature aging and increased risk of skin cancer
- UV radiation can be ionising
uses of x-rays
- medical radiology
radiography to produce x-ray imaging to diagnose fractured bones or tooth decay
radiation therapy to treat cancer - industrial radiology: scan for manufacturing defects in metal parts
- scan luggage for prohibited items
uses of gamma rays
- medical radiology
gamma imaging
radiation therapy to treat cancer - Infdustrial radiology: scan for manufacturing defects in metal parts
- sterilisation of food/medical equipment
Note:
have the highest frequency and most energetic waves
disadv of x-rays and gamma rays
- ionising in nature i.e. radiation that has the energy to remove electrons from atoms or molecules
- exposure can damage biological molecules, living cells and tissues –> cell death, mutations and abnormal cell division
- may cause cancers e.g. leukaemia and/or deformities to a developing foetus
