EM Spectrum Flashcards
As wavelength increases
Frequency decreases and vice versa
Light is part of a what electromagnetic spectrum
Continuous
Speed =
Speed = Frequency x wavelength M/s = Hz x m V = F (lambda)
Highest to lowest frequency of the EM spectrum
Gamma rays X-rays Ultra - violet (UV) Visible light Infra-red (IR) Microwaves Radio waves
4 similarities that all parts of the EM spectrum share
- all transfer energy
- all are transverse waves
- all travel at the speed of light in a vacuum (300 000 000 m/s)
- all can be reflected, diffracted and refracted
What features make groups of electromagnetic waves different from others
Wavelength and frequency
Gamma ray uses
Sterilising equipment and food
Radiotherapy
X-ray uses
X-radiotherapy to observe the internal structure of objects
Ultraviolet uses
Fluorescent tubes
UV tanning lamps
Visible light uses
Seeing communication
Photography
Infra red uses
Cookers + heaters
TV + stereo remote controls
Night vision
Microwave uses
Mobile phone + satellite communication
Cooking
Radio wave uses
Long/medium/short wave radio
TV
Detrimental effect on the body from radio waves
Nil
Detrimental effect on the body from microwaves
Can heat human body tissue ie mobiles
Detrimental effect on the body from infra-red
Skin burns with too much exposure ie hot objects
Detrimental effect on the body from visible light
Nil
Detrimental effect on the body from ultra violet
Harmful to human eyes and skin (melanoma cancer)
Detrimental effect on the body from x-rays
Cancer after many
Detrimental effect on the body from gamma rays
Small dose –> mutation of cells –> becomes cancerous
Analogue signal looks like
A wave
Analogue signal the amplitude does what
Increases and decreases
Digital signal the frequency does what
Remains the same
What happens with the information in an analogue signal
Its converted into electrical voltages that vary
What does a digital signal look like
Castle tops
What happens with the information of a digital signal
Its converted into a sequence of numbers called a binary code which only has 2 digits, 1 and 0, these numbers are converted into a series pf electrical pulses
Received signals are usually
Attenuated
All signals … During transmission as they pick up electrical … And need to be … Or …
Regeneration of digital signals creates a … And … Copy of the original signal
Weaken Noise Amplified regenerated Clean Accurate
When an analogue signal passes through two circuits in a communication system the first part… And the second part….
Regenerates it
removes noise
A digital signal can carry more … Than an analogue signal. …makes a signal difficult to detect. … Changes the shape of a signal waveform. A regenerator circuit removes … From a digital signal
Information
Noise
Distortion
Noise
Speed if light
3 x 10 (power of 8) m/s
Both analogue and digital signals pick up … Noise during transmission the also experience …
Electrical
Attenuation
Analogue signals have their noise amplified which
Reduces the quality of the signal
What sends out microwave energy, a mobile phone sending a text message or a mobile phone mast sending a text message
A mobile phone mast sending a text message
One advantage of using a digital signal
Can carry more information through binary code
Two waves in the spectrum that are most harmful to humans
Gamma rays
X-rays
