The Electromagnetic Spectrum EOY9 Flashcards
(16 cards)
What are the electromagnetic waves in order?
Radio, microwaves, infrared, visible light, ultraviolet, x-rays, gamma rays
List some common features of em waves
They are all transverse
They can all travel through a vacuum
They all travel at the same speed through a vacuum .
Describe the transfere of energy by electromagnetic waves.
Electromagnetic waves can carry energy and so can transfer energy from one point to another point.
Electromagnetic radiation is an energy transfer pathway.
Electromagnetic waves with a shorter wavelength can carry higher energy. This includes ultraviolet, x-rays and gamma rays.
The higher the energy of the MM wave the more dangerous it is.
What is a use of radio waves?
Radio waves are used for communication such as broadcasting, television and radio, communications and satellite transmissions.
Why are radio waves good to use?
Radio waves are transmitted easily through air. They do not cause damage of absorbed by the human body, and they can be reflected to change their direction. These properties make them ideal for communications.
How are radio waves made?
Radio waves can be produced by oscillations in electrical circuits when radio waves are absorbed by a conductor they create an alternating current. This electrical current has the same frequency as the radio waves. Information is coded into the wave before transmission, which can be decoded when the waivers receive. Television and radio systems use this principle to broadcast information.
What are microwaves used for?
Microwaves are used for cooking food, communications and for satellite communications.
Why are microwaves good to use?
High frequency microwaves have frequencies which are easily absorbed by molecules in food. The internal allergy of the molecules increases when they absorb microwaves, which causes heating.
Microwaves pass easily through the atmosphere, so they can pass between stations on Earth and satellites in orbit.
How are microwaves made?
In a mobile phone, they are made by an antenna and a transmitter chip. In a microwave they are made by a magnetron
What are infrared electromagnetic waves used for?
Infrared light is used by electrical heaters, cookers for cooking food, short range communications like remote controls, optical fibres, security systems and high thermal imaging cameras which detect people in the dark.
Why are infrared waves good to use?
Infrared light has frequencies which are absorbed by some chemical bonds. The internal energy of the bonds increases when they absorb infrared light, which causes heating. This makes infrared light useful for electrical heaters and full cooking food.
How is infrared light made?
Infrared radiation is primarily generated by thermal emission from heated object. This means that any object with a temperature above absolute zero emits infrared radiation, with the intensity and wavelength distribution dependent on the object temperature. Additionally, infrared can be produced by other means like lasers and spectral line emmiters
How do microwaves work?
High frequency microwaves have frequency which are easily absorbed by molecules in the food. The internal energy of the molecules increases when they absorb microwaves, which causes heating.
What is a use of visible light?
Visible light is the lights that we can see, so is used in photography and illumination. It is also used in fibre-optic communications, where coded pulses of light travel through glass fibres from a source to
What is ionising radiation?
Ionising radiation:
Ultraviolet waves, x-rays and gamma rays are types of ionising radiation. They can add or remove electrons from molecules, producing electrically charged ions ionisation can have hazard effect on the body.
Ultraviolet waves can cause damage to skin cells and eyes, and increase the risk of skin cancer.
X-rays and gamma rays can cause the mutation of genes, which can lead to cancer.
Which electromagnetic wave is used in satellite communication?
Microwaves are used in satellite communication. Radio waves are a fracture by the ionosphere
