Uses of EM waves Flashcards
What are radio waves most commonly used for?
communication such as broadcasting television and radio, communications and satellite transmissions.
Do radio waves cause damage when absorbed by the human body?
don’t cause damage, are reflected
Explain how radio waves can cause an alternating current
Radio waves can be produced by
oscillations in electrical circuits. When radio waves are absorbed by a
conductor.they create an
alternating current This electrical current has the same frequency as the radio waves.
How do microwaves react to food
They are absorbed by food molecules
How can microwaves be dangerous?
they can internally heat body cells
How do microwaves heat food?
The internal energy of the molecules increases when they absorb microwaves, which causes heating.
How is infrared light used?
electrical heaters, cookers for cooking food, short-range communications like remote controls, optical fibres, security systems and thermal imaging cameras which detect people in the dark
How can infrared light be dangerous?
can cause burns to skin
Why is infrared light used to view people in the dark?
All objects emit infrared light. The human eye cannot see this light, but infrared cameras can detect it. This ‘thermal imaging’ is useful for detecting people in the dark.
how can ultraviolet affect the body
skin to tan or burn
how can ultraviolet be used for sterilisation
it will kill bacteria and can be used for disinfecting water.
