P5.2 Flashcards
what are electromagnetic waves
They consist of oscillating electric and magnetic fields, the fields are oscillating in a direction at 90 degrees to the direction of the wave.
What is the speed of electromagnetic waves
3.0 x 10 to the power of 8 m/s
What does your skin absorb
Your skin absorbs infrared waves and food absorbs microwaves they both heat them up.
What do electromagnetic waves do
They transfer energy from sources to absorbers. Some waves are used to transfer information.
How are radio waves made
An oscillating P.D across a wire makes electrons move backwards and forwards. This produces a changing electric and magnetic field which is emitted as a radio wave. When the field meets another piece of metal, such as an aerial it makes electrons move, which produces a signal.
What is the order of electromagnetic waves in increasing wavelength
Gamma rays, X-rays, ultraviolet, visible light, infrared, micro-waves, radio waves
What is the order of electromagnetic waves in increasing frequency
Radio waves, micro waves, infrared, visible light, ultraviolet, X-rays, gamma rays
What do your phones use to communicate with
They communicate with transmitters using microwaves. Microwaves are also used to communicate with satellites and bluetooth systems.
What do remote controls use
They use remote controls use infrared to send signals to tv
What are infrared and microwaves used for
Fat and water in food absorbs the microwaves which heats up outside of the food. Infrared radiation is used to cook on a grill.
What is U.V light used for
To detect bodily fluids.
How can electromagnetic ways be used in terms of germs
Ultraviolet radiation kills bacteria in water
X rays can kill skin cancer or other cancer cells
Gamma rays can kill cancer cells and bacteria on food
What can thermal imaging cameras use
A thermal imaging camera producers an image called a thermogram that shows regions of different temperatures. A CCD absorbs the radiation and produces an image. Colour is then added by a computer.
What does your skin emit more due to injury and infection
Infrared radiation if it is hot
How are X-rays used for imaging
An X-ray can show if your arm is broken. Bones absorb X-rays but soft tissues such as skin and muscle don’t. Photographic film darkens when it absorbs X-rays and shows the details of the internal structure of a person.
