P12 - Electromagnetic Waves.

P12 - Electromagnetic waves.

Gamma - heighest frequency.

• Human eye can only detect visible light which has a wavelength of 350nm to 650nm.
• Electromagnetic waves tranfer energy from source - absorber.

• wavespeed = frequency x wavelength.

• white light - all colours of spectrum
• Infared - carrying signals from remote controls and optical fibres. 
• Microwaves - satellite tv programmes and phone calls.
• Radiowaves - radio and TV broadcasting and phone calls.
• Mobile phone radiation is microwave radiation and radiowaves .
• different types of elctromagnetism are dangerous.
• Microwaves and radiowaves heat internal body parts.
• Infared - skin burns

• wavelength affects; how far they travel, how much they spread and how much info they carry.
• Futher reaserch needed - are phones safe to use?
• Carrier waves used to carry info. They do this by varying amplitude.
• Optical vibres - thin, transparent. Used to transmit communication signals by light and infared radiation.

• Ultraviolet - shorter wavelength than visible light and can harm skin and eyes. 
• X-RAYS - hospitals to make X-ray Images. 
• Gamma rays kill bateria in food, sterilise equipment and kill cancer cells. 
• Ionising radiation - uncharged atoms become charged. 
• X-rays and GAMMA damage living tissues.

• used in hospitals to; 
• make images of internal body parts
• destry tumours near body surface. 

• They are ionising rdiation so can damage living tissue . 

• Absorbed by bones and teeth more than soft tissue. 

• People who work in X-ray areas must wear protective lead.