Waves ( The electromagnetic spectrum) Flashcards
Topic 2 C
Types of radiation in the electromagnetic spectrum (7)
- radio
- microwave
- infrared
- visible
- ultraviolet
- x-ray
- gamma ray
electromagnetic waves are
electric and magnetic disturbances that transfer energy to one point to another
electromagnetic waves all (4)
- carry and trasnfer energy
- are transverse waves
- all travel at the speed of light
- all can be reflected, refracted and difracted
what is the speed of light
3 x 10⁸ m/s
electromagnetic waves all travel through ___ and so need / don’t need a medium
vacuum
no medium
order of the electromagnetic waves from low frequency and long wavelength to high frequency and short wavelength
radio
microwave
infrared
visible light
x-rays
gamma rays
an increase in wavelength means a ____ in frequency
decrease
which is the only part of the EM detectable by the human eye
visible light
in visible light, which colour has the longest wavelength and lowest frequency
red
in visible light, which colour has the highest frequency and shortest wavelength
violet
what are the colours of the visible spectrum in order of decreasing wavelength (7)
red
orange
yellow
green
blue
indigo
violet
mnemonic to help remember colours of visible spectrum
ROYGBIV
Raging Martians Invaded Venus Using X-ray Guns
uses of radio waves
broadcasting and communications like television and mobile phones
uses of microwaves
cooking and satellite transmissions
uses of infrared radiation
heaters and vision equipment
uses of visible light
optical fibres and photography
ultraviolet uses
fluorescent lamps
x-rays uses
Observing the internal structure of objects and materials, including medical applications
gamma rays uses
Sterilising food and medical equipment
electromagnetic waves all travel at ___ speed
SAME
properties of light waves (4)
- travel in straight lines
- an electromagnetic wave
- travels at 3 x 10⁸ m/s
- different colours have different frequencies / wavelengths
both radio and microwaves are used in ___ communication like ___
wireless
radios, mobile phone communication
microwaves are used to heat things in a microwave oven at ___ intensities
very high
infrared is emitted by
warm objects
infrared can be detected by
thermal imaging cameras
examples of uses of infrared
Security cameras to see people in the dark
TV remote controls
Transport signals down fibre optic cables
ultraviolet can give you a
sun tan
what is the process of fluorescence ( ultraviolet)
When certain substances are exposed to ultraviolet, they absorb it and re-emit it as visible light (making them glow)
Fluorescence can be used to
secretly mark things in special ink, such as banknotes
x-rays are absorbed by what part of the body
dense parts like bones
gamma rays can be dangerous as they can
kill cells and living tissue
gamma rays sterilise equipment by
killing off the bacteria
dangers or risks of overexposure of microwaves can cause
heat damage to internal organs due to the internal heating of body tissue
dangers or risks of overexposure of infrared can cause
skin burns
dangers or risks of overexposure of ultraviolet can
damage skin cells causing sunburn and blindness
dangers or risks of overexposure of gamma and x-rays can
kill cells causing cancer and cell mutations
why are radio waves used for long - range communication
BECAUSE THEY CAN BE
REFLECTED FROM THE EARTH’S ATMOSPHERE
why are microwaves used for satellite communication
REASON: BECAUSE
MICROWAVES CAN
PENETRATE EARTH’S
ATMOSPHERE
why are infrared waves used for optical fibre communication
BECAUSE
THEY CAN UNDERGO
TOTAL INTERNAL
REFLECTION
why is visible light used for videos and photos
CAMERAS
ARE SET UP TO DETECT VISIBLE
LIGHT
why are ultraviolet used fro fluorescent lamps
because process of fluorescence happens
why are x-rays used for medicine ( x-rays)
REASON: BECAUSE
X-RAYS CAN
PENETRATE SOFT
TISSUES BUT NOT
BONE
why are gamma rays used to sterilise medical tools
BECAUSE
GAMMA KILLS
BACTERIA
danger associated with EM waves increases along with the frequency because
Beyond the visible part of the EM spectrum, the energy becomes large enough to ionise atoms
The shorter the wavelength, the more/less ionising the radiation
more
protective measures against microwaves used
microwaves from microwave ovens are prevented from escaping the oven by the metal walls and metal grid in the glass door
protective measures against infrared used
infrared wearing protective clothing such as gloves can prevent the skin from feeling the hear
protective measures against ultraviolet used
ultraviolet ray damage to the eyes is reduced by wearing sunglasses that absorb ultraviolet and prevent it from reaching the eyes.
Sunscreen also absorbs ultraviolet light preventing it from damaging the skin.
protective measures against gamma and x-rays used
gamma and X-rays damage is reduced through using minimal levels in medicine.
Doctors leave the room during x-rays to avoid unnecessary exposure.
Radiographers wear radiation badges to measure their level of radiation exposure.
People working with gamma rays routinely have their dose levels tested.
