The Electromagnetic Spectrum Flashcards
https://www.thinglink.com/scene/786642971607957505
https://en.wikipedia.org/wiki/Wave_height
wavelenght?
wavelength is the length of a wave, it is measure from 1 point on a wave to an identical point on the next wave
amplitude?
amplitude is the height of a wave, it is measure from the midpoint to the peak/trough
Frequency?
Frequency is the number of waves that pass a fixed point every second: measured in Hertz (Hz)
Time Period?
Time taken for a full wave to pass a point: measured in seconds
Time period (S) = ?
Time period (S) = 1 / frequency (Hz)
What are the two kinds of waves?
- Transverse
2. Longitudinal
For waves travelling at the same speed, shorter wavelength = ?
Higher frequency
Wavelength and frequency are?
Inversely proportional
wave speed =?
frequency (Hz) * wavelength (M)
What are the waves in the EM spectrum (longest to shortest wavelength)?
- Radio waves
- Micro waves
- Infrared Radiation
- Visible Light
- Ultraviolet
- X-Rays
- Gamma Rays
What speed do all EM waves travel at?
The speed of light - in a vacuum is 300 mil m/s
What kind of waves are EM waves?
Transverse
What are radio waves used for mainly?
communications - tv and radio
What do radio waves, microwaves, infrared radiation and visible light all have in common?
They have the longest wavelengths
Why are waves with longer wavelengths used for communications?
- They can travel further
2. They’re not dangerous
What are microwaves used for?
- satellite communications - including Sat TV
- mobile phones
- Microwave ovens - these heat up food faster than ordinary ovens because microwaves can penetrate food and are absorbed by water molecules in food - heating it up.
What is infrared radiation used for?
- to send tv remote signals
- night vision and heat sensing cameras
- can be used in optical fibres - normally however visible light is used
What is visible light used for?
- our eyes can see visible light, so any methods of visible communication relies on visible light
- tv
- photography
- optic fibres (broadband)
Light from the sun (or ordinary lamps) is called?
white light because it has all the colours of the visible light spectrum in it
as the wavelength shortens…
the wave becomes more dangerous
What is ionising radiation?
waves with short wavelengths have enough energy to knock electrons off the outer shells of atoms, damaging the cell the atom is apart of, and even making the cell cancerous
Ultraviolet wave uses?
- To detect forgeries at banks
- tan beds
- bee’s use UV rays to detect pollen
How many types of UV rays are there?
ultraviolet A (UVA), ultraviolet B (UVB), and ultraviolet C (UVC)
UVC?
UVC rays can’t pass through the ozone layer therefore only harmful in space
UVB?
Affects top layer of skin, makes you tanned, red, burnt, can cause cancer
UVA?
UVA is actually more dangerous than UVB because although UVB has a shorter wavelength, it is the perfect wavelength to be absorbed by the top layer of skin and therefore UVA penetrates deeper.
DNA damage + skin aging
Uses of X-Rays?
- medical imagery
2. metal detectors
How do medical professionals who use x-rays protect themselves?
- They leave the room
- They wear lead aprons
- They go behind screens
- Limit exposure time
Uses of gamma rays?
- Radiotherapy
2. Sterilize medical equipment
Gamma knife?
Targeted gamma rays that can destroy tumours
How are radio waves produced?
Oscillations in electrical circuits
How are microwaves produced?
Produced in microwaves and other transmitters
How is infrared radiation produced
Radiated from any object with a temperature
How is visible light produced?
Comes from the sun
How is ultraviolet radiation produced
High temperature surfaces such as the sun produce it
How are x-rays produced?
By accelerating electrons through a potential diffference
How are gamma rays produced?
By nucleus changes of an atom
