Microwaves - Working Principle Flashcards
The working principle of a microwave is described under five headings, name these headings
Transformer
Magnetron and wave stirrer
Reflected and transmitted
Absorbed
Standing time
Describe the working principle of the transformer
When a microwave is plugged in and switched on, the transformer increases the normal domestic voltage from 230 V to a much higher frequency needed to produce microwave (electromagnetic) energy
Describe the working principle of the magnetron and wave stirrer
The magnetron converts the electrical energy into microwave energy, which enters the oven via the wave guide and is distributed evenly by the wave stirrer
What does the magnetron convert into microwave energy?
Electrical energy
What converts electrical energy into microwave energy?
The magnetron
What does the magnetron convert electrical energy into?
Microwave energy
How does microwave energy enter the oven?
Via the wave guide
How is the microwave energy distributed evenly?
By the wave stirrer
Describe the working principle of the reflection and transmition of microwaves.
Microwaves reflect off the metal-lined oven cabinet and transmit through the cooking container to the food inside
What do microwaves reflect off in the oven cabinet?
They reflect off the metal-lined oven cabinet
What do microwaves transmit through?
They transmit through the cooking container to the food inside
Describe the working principle of the absorption of microwaves.
(3)
The microwaves penetrate the food two to five centimetres deep, and are absorbed by the particles of water, sugar and fat
The particles begin to vibrate, creating friction or heat
This cooks food by conduction
How deep do the microwaves penetrate the food?
They penetrate the food two to five centimetres deep
What absorbs the microwaves in food?
The particles of water, sugar and fat absorb the microwaves
What happens to the particles when they absorb the microwaves (electromagnetic energy)?
They begin to vibrate, creating friction or heat
