Microwaves Flashcards
What is the wavelength of microwaves?
around 1cm
What are microwaves used for?
satellite communications and microwave ovens
How are microwaves used in satellite communications?
Microwaves can pass easily through the atmosphere. So they are used to send signals to satellites which can send the signals on to distant locations. The satellites orbit the Earth, thousands of kilometres above the surface. The returned signal is received by a satellite dish.
Why are microwaves absorbed by foods?
High frequency microwaves have frequencies which are easily absorbed by molecules in food.
How do microwaves ovens work?
In microwave ovens, microwave radiation is emitted by the oven and then absorbed by water molecules in the food. This energy heats up the water molecules, which also heat up the surrounding molecules via heat transfer.
What is the 1st step for what happens in satellite TV?
the signal from the transmitter is transmitted into space where it’s picked up by the satellite receiver dish orbiting thousands of kms above the Earth.
What is the 2nd step for what happens in satellite TV?
the satellite transmits the signal back to earth in a different direction where it’s received by a satellite dish on the ground - there’s a slight time delay in the signal being sent and received cos of the long distance the signal has to travel.
