electromagnetic spectrum

electromagnetic spectrum

spectrum of waves with similar properties

what are the seven groups of electromagnetic waves?

radio waves, microwaves, infrared, visible light, ultraviolet, x-rays and gamma rays

how does the electromagnetic spectrum change?

it starts with waves with a very long wavelength, low frequency and low energy and changes to waves with a very short wavelength, high frequency and high energy

what does visible light contain?

all the frequencies that can be detected by the human eye

\-red light has the lowest frequencies of visible light

\-violet light has the highest frequencies of visible light

what are radio waves used for?

communication e.g. television and radio

what are microwaves used for?

\-cooking food

\-satellite and mobile phone communications

what is visible light used in?

\-fibre optic communications

\-to see

\-astronomy/microscopy

what is ultraviolet used for?

\-UV lamps

\-checking bank notes

\-detecting security markings

\-tanning

what is infrared (IR) used for?

\-cooking

\-electric heaters

\-night vision/IR cameras

what are x-rays used for?

\-viewing dense objects such as bones (medical imaging)

\-security scanners (e.g. in airports)

what are gamma rays used for?

\-medical imaging

\-cancer treatment (radiotherapy)

how are radio waves different to sound waves?

\-radio waves are transverse

\-radio waves travel at a higher speed

\-radio waves don’t need a medium

\-radio waves are electromagnetic

The car aerial is connected to an electrical circuit in the car. Describe what happens in the electrical circuit when the car aerial absorbs radio waves.

\-(alternating) current induced (in the electrical circuit)

\-with the same frequency as the radio wave

what are the dangers of radio waves?

There are no known dangers but there are suspicions of cancer if exposed for long periods.

what are the dangers of microwaves?

\-melting of internal organs and tissue

\-possible cancer if exposed for long periods