Electromagnetic Waves 2 Flashcards
What do electromagnetic waves form?
A continuous spectrum
What are uses of gamma rays?
Medical imaging
Radiotherapy
How are x-rays produced?
By the rapus deceleration of free electrons
By changing in the organisation of the elctribs that orbit the nuclei of atoms
What are uses of X-rays and why?
Pass easily through soft body tissue but are absorbed more effectively by bone
Medical imaging
Medical treatment
What are hazards related to UV radiation?
Sunburn
Skin cancer
Blindness
What are uses of UV?
Process called fluorescence
A fluorescence substance can absorb UV radiation
The emits longer-wavelength visible light
Energy saving light bulbs
Security ink
Smarrwater
What are high frequency hazards?
Gamma, X and UV rays lie at the high frequency of the spectrum
The energy they deposit within the body can ionise the atoms that make up cells
This can lead to mutations to cells in the body which can cause cancer
What is radiation dose what is the unit
The dose we receive from an exposure to one of these types of electromagnetic radiation tells us how harmful it is likely to be on our health
Sievert, Sv
How many Sievert does the average person in the UK receive?
2.7 mSv from all sources of background radiation
What are uses of visible light?
Human sight
Lasers
Fibre-optic communication
What is the order of the 7 main colours of the visible spectrum?
Red - Richard
Orange - Of
Yellow - York
Green - Gave
Blue - Battle
Indigo - In
Violet - Vain
What is another way to refer to infrared radiation?
Thermal radiation
What are uses of infrared?
Electrical heaters
Cookers
Infrared cameras
What are uses of Microwaves?
Microwave oven
Mobile phone networks
Satellite communications
Bluetooth
Why are microwaves used for satellite communication?
Pass easily through the Earth’s Atmosphere
What are uses of radio waves?
Radio and television signals
Radar
How is radio wave produced?
An electrical signal uses electrons to oscillate up and down the transmitting antenna
This leads to the production of radio waves. Which travel from the transmitter to the receiver.
In the receiving antenna energy from the incident radio waves causes electrons in this antenna to oscillate up and down, which can be detected as an electrical signal in the antenna
This electrical signal is what carries the radio or television broadcast to the receiver
What cube is used for the required practical?
Leslie Cube matt and shiny black and white surfaces
I’m what surface is infrared absorbed more, shiny black or matt white?
Matt white
What kind of variable is surface?
Categoruc variable
