Physics Waves 2 Flashcards
What is the electromagnetic spectrum ?
It is a range of types of radiation and their wavelengths. The range covers radiation of different energies and wavelength
If, in the electromagnetic spectrum, the wavelength is long, is the frequency in hertz (Hz) low or high?
Low
Low frequency waves have long wavelength (1000m)
High frequency waves have very short wavelengths 1 x 10 -6 m
Try to learn Rich Men in Vegas Use X-ray Glasses to help you remember the order of different types of wave types in the electromagnetic spectrum
R radio waves
M Microwaves - used in our microwave oven
I infra red waves
Visible , this is ‘light’ that can be seen by the human eye
X rays , this is the radiation used to take pictures of your teeth and bones
Finally in the electromagnetic spectrum,
Gamma rays
The visible spectrum in the electromagnetic spectrum is what we can see, what word beginning with l is used to describe this?
Light or visible light.
About different types of waves and radiation in the electromagnetic spectrum.
Radio waves…..
No known dangers
Used for TV and radio
About different types of waves and radiation in the electromagnetic spectrum.
Microwaves……
Can cause burning
Used or cooking and satellite communication
About different types of waves and radiation in the electromagnetic spectrum.
Infrared radiation……..
Can can burning
Emitted (given out) by hot objects
Used for electric heated, cookers and infrared cameras
About different types of waves and radiation in the electromagnetic spectrum.
Visible light
We can see it
Very bright light can cause blindness
Has an application (use) in fibre optics
About different types of waves and radiation in the electromagnetic spectrum.
Ultaviolet
Ionising, can cause skin cancer
Use in sun tanning beds
Used in sterilising
About different types of waves and radiation in the electromagnetic spectrum.
X rays and gamma rays
Can cause cancer
Used in medical imaging (tooth and bone x rays in limited doses)
Also radiotherapy treatments (used in cancer treatment to kill cancer cells)
What does ionising mean?
Knocking electrons off atoms.
UV and x Rays and gamma rays can have an ionising effect on matter.
What is the speed of light?
Around 300 million metres a second!
What kind of electromagnetic wave transfers heat from one place to another?
Infrared radiation
Some surface and good absorbers and emitters of radiation (these surfaces are good at taking in and giving out radiation). What surfaces are good at absorbing and emitting?
Matt black surfaces
In the summer black trousers feel hotter than white trousers, this is why cricketers wear whites
Some surface and good absorbers and emitters of radiation (these surfaces are good at taking in and giving out radiation). What surfaces are the WORST at absorbing and emitting?
Smooth shiny surfaces are the worst, they reflect IR (infrared waves) rather than absorbing it.
We wrap food in foil that we want to keep fresh, so that it won’t absorb heat.
