Topic 6, Part 2 - Waves Flashcards
what are Em waves made from
made up of oscillating electric and magnetic fields
how are electromagnetic waves produced
alternating current are made up from oscillating charges. as charges oscillate, they produce oscillating electric and magnetic fields.
what will the frequency produce be equal to
it will be equal to the frequency of the alternating current.
how can you produce radio waves
using an alternating current in an electrical circuit. the object in which charges (electrons) oscillate to create the radio waves is called a transmitter.
what happens to transmitted radio waves
the waves reach the receiver and then are absorbed.
how does the receiver use the waves its absorbed
the waves that were received transfers the electrons that were carried to the receiver
what happens with the electrons after they have been received
the energy cause the electrons to oscillate and, if the receiver is a part of the electrical circuit, generates an alternating current
what are microwaves used for
they are used for satellites but you need microwaves that can pass through the earth’s watery atmosphere
why do microwave ovens use different wavelengths
in microwaves the waves need to be absorbed by the water molecules in food so they have different wavelengths
what are infrared radiation used for
infrared radiation can be used to increase and monitor temperature. everything gives out infrared so the hotter something is the more it gives out.
what three types of radio waves are there
long-wave radio - 1 to 10Km transfer around world by bending around surface of earth. transmit things
short-wave radio - 10m to 100m transfer by reflecting from the ionosphere. bluetooth
meduim-wave - shortest ones, reflect of ionosphere. tv
what are visible lights used for
fibre optic cables that carry data over long distance, using visible light.
what are ultraviolet radiation used for
fluorescence is a property of certain chemicals, where ultra-violet radiation is absorbed then visible light is emitted.
What are X-rays and Gamma rays used for
they are used for X-ray scans and use x-rays and gamma rays for treatment for cancer.
what are the dangers of Em radiation
EM radiation can enter living tissue and can sometimes cause illnesses.
