EM Waves and Their Uses Flashcards
What two categories do microwaves spilt into
those absorbed by water molecules and those not absorbed by water molecules
Example of microwaves that aren’t absorbed by water molecules
microwaves
How do microwaves that aren’t absorbed by water molecules transfer signals
they have to pass through the earth’s atmosphere. They are then received by satellites and then they are transmitted back to earth
How do microwaves that are absorbed by water molecules transfer signals
when microwaves are fired at the food, the energy from the waves gets absorbed by the water molecules. The molecules then start to vibrate with the new energy and some of the energy spread to other molecules until the food is heated up
Where is IR energy emitted from
All energy that has thermal energy
Example of IR waves
infrared cameras that see in the dark
True or false
the hotter the organism to the darker the colour of the infrared wave
False. the brighter the colour
How is infrared used in cooking
By heating up the metal bar in ovens, It emits lots of infrared radiation and this heats up the food
How is infrared used in heaters?
By heating up the metal bar, it emits lots of infrared radiation and it gets transferred to the surroundings
How dangerous are infrared are microwaves
They are only harmful in high quantities
What do we use visible light to do
see idiffrent colours and comunicste
What are optical fibers`
thin glass/ plastic fibers that can transmit forces of light over long distances. The light bounces back and forth until it gets to the end of the beam. You have to use materials that will totally reflect light
What is the alternative for optical fibers?
Electrical copper wires
What is Ultraviolet
waves that come from the sun
how do we use ultraviolet
as things like sunbeds, security pens
