Electromagnetic waves, electromagnetic spectrum Flashcards
Electromagnetic waves
Are transverse waves their vibrations or observations are changes in electrical and magnetic fields at right angles to the direction of wave travel
All electromagnetic wave
Transfer energy as radiation from the source of waves to an absorber
Can travel through a vacuum such as in space
Travel at the same speed through vacuum or the air they travel at 300,000,000 m/s through a vacuum
Electromagnetic spectrum waves form a continuous spectrum of waves that include
Ways with a very short wavelength, high frequency and high energy
waves with very long wavelength, low frequency and low energy
The order of electromagnetic spectrum, seven distinct groups
Radio waves microwaves infrared
then in the middle visible light (rainbow colour)
ultraviolet x-rays gamma rays
Goes from long wavelength, low frequency, low energy to short wavelength, high frequency, high energy
Phrase used to help remember the order of groups of the electromagnetic spectrum
Roman men invented very unusual x-ray guns
Radio waves
Microwave
Infrared
Visible light
Ultraviolet
X-ray
Gammaray
Each group contains a range of frequencies
Red light has the lowest frequency of visible light
Violet light has the highest frequency of visible light
Radio waves
Are use for communication such as broadcasting and television and radio communications and satellite transmissions
How are radio waves transmitted through the air?
Transmitted easily through the air they do not cause damage if absorbed by the human body they can be reflected to change their direction. These properties make them ideal for communication communications.
Produced by oscillations radio waves
They can be produced by oscillations in electrical circuit when radio waves are absorbed by conductor they create an alternating current. This electrical current has the same frequency as the radio waves information is coded into the way for full transmission which can then be decoded when the wave is received television and radio systems use this principle to broadcast information.
Microwaves
They are useful cooking food communications and satellite communications. Intense sources of microwaves can be dangerous through internal heating of body cells.
Microwaves higher
High frequency microwaves have frequencies which are easily absorbed by molecules in the food. The internal energy of the molecules increases when they absorb microwaves which causes heating microwaves pass easily through the atmosphere so they can pass the train stations on earth and satellites in orbit.
Infrared
Light is used by electrical heaters, cookers for cooking food short range communications that remote controls optical fibre security systems and thermal imaging cameras which detect people in the dark heating effect of infrared cause burns to the skin
Infrared higher
Has frequencies which are absorbed by some chemical bonds. The internal energy of the bond increases when they absorb infrared light which causes heating. This makes infrared light useful for electrical heaters and for cooking food all objects in emit in a red light the human eye cannot see the light but infrared cameras can detect it. This thermal imaging is used for detectingpeople in the dark.
Visible light
Is the light we can see so is used in photography and illumination. It is also used in Viber optimistic communications work who did pulses of light travel through glassfibre from a source to receiver.
Use of long wavelength of electromagnetic waves
Radio waves, microwaves, infrared and visible light the first four types of EM waves
Uses of short wavelength, electromagnetic waves
Ultraviolet Ian waves in medicine and ionising radiation
Ultraviolet
We can’t see ultraviolet UV light but it can have hazardous effects on the human body. Ultraviolet light in sunlight can cause the skin to tan or burn fluorescent substances are used in energy efficient labs. They absorb ultraviolet light produced inside the lamp and remit the energy as visible light similar substances are used on bank note to detect for the hazardous properties of UV mean it will kill bacteriaand can be used for disinfecting water
Electromagnetic waves in medicine
Changes in atoms and the nuclei can cause electromagnetic waves to be generated or absorbed rays are produced by changes in the nucleus of an atom. They are a form of nuclear radiation high energy waves such as x-rays and rays are transported through the body tissue with very little absorption this makes them ideal for not internal imaging x-raysare absorbed by dense structures like bones which is why x-ray photos are used to help identify broken bones.
X-ray imaging
Used for scanning the internal structure of objects and an airport security scanners or to see inside the body like broken
Gamma rays
Sterilising food and medical instruments and in the treatment and detection of cancer
Ionising radiation,
Ultraviolet waves x-rays and gamma rays are types of ionising radiation. They can add or remove electrons from molecules producing electrically ions. Ation can have hazardous effect on the body.
Ultraviolet waves use
Can cause damage to skins cells and eyes and increase the risk of skin cancer
X-ray gammaray use
Can cause the mutation of jeans which can lead to cancer
Infrared radiation, the hotter the body
The more infrared radiation it gives out in a given time the greater proportion of emitted radiation is visible light
