EM waves Flashcards
(24 cards)
what happens when em waves are generated or absorbed
changes take place in the atoms or in the nuclei of atoms
how is em generated (atoms) through heating
when heated, electron gets excited and moves to next energy level
-as it moves back down, an em wave is emitted
how are em waves generated through gamma rays
ray is emitted
nucleus has less energy that it has at start
hazards of radio and microwaves
can penetrate the body and cause internal bleeding
hazards of infrared
can damage or kill skin cells due to heating
hazards of visible loght
can damage retina
hazards of UV
-can damage skin cells
-causing skin to age prematurely
-increases risk of skin cancer
-can also cause blindness
uses of radiowaves
television, radio signals
uses of microwaves
satellite communications, cooking food
uses of infrared
electric heaters, cooking food, infrared cameras
uses of visible light
fibre optic communications
hazards of x rays and gamma rays
forms of ionising radiation
so can:
-can damage/kill cells
-causing mutation of genes
-leads to cancers
hazards of x rays and gamma rays
forms of ionising radiation
so can:
-can damage/kill cells
-causing mutation of genes
-leads to cancers
uses of ultraviolet
energy efficient lights
artificial sun tanning
uses pf x and gamma rays
medical imaging
&treatments
how are radiowaves produced
when electrons oscillate in electrical circuits
what happens when radio waves are absorbed by electrical circuit in an arial
-cause electrons in circuit to also oscillate
-producing an alternating current with same frequency as radiowaves
what does each colour have
its own narrow band of wavelength and frequency
what is diffuse reflection
reflection of a bumpy surface
which does not produce an image
what is specular reflection
when all light rays reflect in single direction
takes place on smooth surfaces
produces an image
what happens when u pass white light through a prism
spits into a spectrum
how do coloured filters work
by absorbing specific wavelengths and transmitting other wavelengths
difference between transparent and translucent objects
transparent objects transmit visible light
translucent objects transmit visible light but light rays are SCATTERED or REFRACTED inside them
what are opaque objects
objects that we cannot see through at all
