AQA - GCSE - P1b5 - The Electromagnetic Spectrum

-They are electric and magnetic disturbances
-Move energy from place to place
-Can travel through a vacuum
-Travel at 300 million m/s
-Wave speed = frequency x wavelength
-Bigger the amplitude – more energy being transported
-Frequency – number of waves a second (high frequency, high energy)
-Wavelength – length of wave (long wavelength, low energy)

From longest wavelength to shortest:
radio waves
microwaves
infra-red
light
UV
X-rays
gamma

-Transmit TV and radio programmes.

-When an alternating voltage is applied to an aerial, it emits radio waves with the same frequency as the alternating voltage. When the waves are received, they produce an alternating current with the same frequency as the radiation.

-Cooking, communications

-Produce frequencies which are absorbed by water

-Heat the water in food so it cooks from the inside out

-Water in living cells will absorb microwaves

-Given out by all objects – the hotter it is, the more given out

-Night-vision works by using infra-red

-Absorbed by skin and it can burn us

-We sense it as heat

-Can be transmitted down optical fibres

-Can be transmitted along optical fibres

-We see the different wavelengths as colours

-Causes skin to tan, age and get cancer

-Can damage eyes

-Fluorescent lights absorb the UV they produce

-Produce shadow pictures of bones

-Can pass through soft body tissue

-Make cells cancerous

-Stopped by lead

-Sterilise things

-Keep food fresh for longer by killing the bacteria on it

-Can pass through soft body tissue

-Will damage cells – can make them cancerous

-Hospitals

-Kill cancer

-Stopped by lead