Electromagnetic Spectrum Flashcards
Order of the spectrum from highest frequency
Gamma rays X rays Ultraviolet Visible light Infra red Microwaves Radio waves
What is the electromagnetic spectrum?
When white light is split up into a spectrum of many different colours and visible light is just part of the continuous spectrum of electromagnetic radiation
Similarities with the spectrum
They all transfer energy
They are all transverse
All travel at the speed of light in a vacuum
Can all be reflected refracted and defracted
What differentiates the waves
Frequency and wavelength
Radio waves
For communication
No effect on body
Microwaves
For cooking foods
Heat human body tissue cause harm to the brain
Infra red
Cookers heater stereo remote
Cause skin burns when too much exposure
Visible light
Seeing and photography
No effect on body
Ultraviolet
Fluorescent tubes and tanning
Skin burns and blistering
Cancer and blindness
X rays
X radiography
Overexposure can lead to cancer
Gamma rays
Sterilising equipment and food
Damage to living cells and causes gene mutations
What is a regenerative circuit?
It allows an electronic signal to be amplified many times by the same active device. It makes a clean, accurate copy of the original digital signal without amplifying any accompanying noise
Digital signals
Can only take 2 values
These values are just on/off
A series of pulses in just two states
Analogue signals
They can take any value within a range
The amplitude and frequency can vary continuously
Eg. Music and speech
Advantages of digital signals over analogue
They both weaken as they travel
They pick up interference or noise
When analogue signals are amplified the noise is too,
Digital signals the noise is just ignored
It’s easier to transmit multiple signals
Can carry more info per second
Maintain quality over longer distance
