Electromagnetic Spectrum Flashcards
What are the different waves in the electromagnetic spectrum, in order?
Radio waves, micro waves, infra red, visible light, ultra violet, x-rays and gamma rays.
What is the frequency and wavelength like in the electromagnetic spectrum?
As you go up the spectrum (radio-gamma), the frequency increases and the wavelength decreases.
What are electromagnetic waves?
Electromagnetic waves are transverse waves that transfer energy from a source to an absorber. They travel at the same speed through air or a vacuum (space).
What are radio waves and what are they used for?
Radio waves are mainly used for communication (television and radio). They are produced by oscillations. When the waves are absorbed by a conductor, an alternating current is created. This alternating current is coded with information before transmission and then is decoded once received.
What are microwaves and what are they used for?
Microwaves are used for cooking food and for satellite connections. High frequency microwaves have frequencies which are easily absorbed by molecules in food. These internal energy of the molecules increase when they absorb the microwaves, causing them to heat up. Microwaves can pass easily through the atmosphere, meaning they can pass between stations on Earth and satellites in orbit.
What are infrared light and what is it used for?
Infrared light is used for electrical heaters, cookers and infrared cameras. Infrared light has frequencies which are absorbed by some chemical bonds. The internal energy of the bonds increases when they absorb the infrared light, causing heat. All objects emit infrared light which is naked to the human eye, but infrared cameras can detect it.
What is visible light and what is it used for?
Visible light is light we can see. It’s used in fibre optic communications, where coded pulses of light travel through glass fibres from a source to a receiver.
What is ultraviolet light and what is it used for?
Ultraviolet light in sunlight causes the skin to tan or burn. Fluorescent substances absorb ultraviolet light produced inside the lamp, and re-emit the energy as visible light.
What are x-rays and what are they used for?
X-rays can be used in medicine for taking photos of bones. X-rays are transmitted through the body tissues with very little absorption, x-rays are absorbed by dense structures like bones.
What are gamma rays and what are they used for?
Gamma rays are produced by changes in the nucleus of an atom, they are a form of nuclear radiation. Gamma rays can be used to treat patients with cancer, the gamma rays are directly shot at the cancer cells in the body to kill them.
Which waves are ionising?
Gamma rays, ultraviolet light and x-rays are ionising.
Which waves are non-ionising?
Visible light, infrared light, microwaves and radio waves are non-ionising.
What are some dangers of electromagnetic waves?
1) High doses of ultraviolet light can cause sunburn and premature aging.
2) X-rays and gamma rays can cause gene mutation or cell destruction, and cancer.
What is radiation dose?
Radiation dose is a measure of the risk of harm caused by exposing the body to ionising radiation.
What is radiation dose measured in?
Millisieverts, 1000mSv = 1Sv
