Flashcards in P13 - Waves Deck (19)
As the electromagnetic spectrum goes down...
• The wavelength decreases
• the frequency increases
• radio waves
• micro waves
• visible light
• ultraviolet radiation
• gamma rays
Wavelengths the eye can detect?
From 350nm to 650nm
Electromagnetic waves transfer...
Energy from source to absorber.
Infrared is used for...
Carrying signals from remote control handsets and inside optical fibres.
Microwaves are used for...
To carry satellite TV programs and mobile phone calls.
Radio waves are used for...
Radio communications and mobile phone calls.
Mobile phone radiation is...
Microwave radiation and also radio waves at near-microwave frequencies.
How are microwaves and radio waves hazardous?
Heat internal parts of the body.
How can infrared radiation cause damage to people?
Cause skin burns.
Frequencies of the radio wave determine...
• how far they can travel
• how much they spread
• how much Info they carry
Waves used to carry information. They do this by varying their amplitude.
What is an optical fibre?
Thin transparent fibres that are used to transmit communication signals by light and IR radiation - reflects light and radiation. More secure as signal stays in fibre.
Causing the atom to loose an electron and become charged, meaning it can react and could cause cancer. Can damage and kill cell.
How is ionising radiation dangerous?
In cell, damages or kills it. In large doses kill, low doses cause gene mutation - cancer
X-rays are absorbed more by...
Bones and teeth then soft tissue.
Difference between x-rays for imaging and for therapy?
Therapy have shorter wavelengths
Why do satellites use microwaves instead of radio waves?
microwaves can penetrate earths atmosphere but radio waves are reflected