13.1-13.3 Flashcards
what do electromagnetic waves transfer
energy
does wavelength get bigger or smaller as you go from left to right across the EM spectrum
smaller
how do you calculate wave speed
wave speed=frequency x wavelength
the shorter the wavelength the higher the…?
frequency
what type of light is from the sun and ordinary lamps
white light
what happens to wavelength in the light spectrum as you go from violet to red
increases
what happens to light in a film camera
light is focused by the camera lens on to light sensitive film, the film then needs to be developed to see the full image
what happens to light in a digital camera
the light is focused by the lens on to a sensor, this makes thousands of pixels , which creates the full image
how does the temperature of an object effect the amount of infra red radiation it gives of
the hotter the object is the more infrared radiation it gives off
what happens to infrared radiation around the body
it is absorbed by the skin and can damage, burn, or kill skin cells as it heats them up
what type of wave do optical fibers use and why
optical fibers in communication use infrared radiation as it is absorbed less than visible light in the glass fibres
what type of radiation do remote controls use to communicate with the main device and why
infrared radiation as they can be easily produced and detected electronically
what are infrared scanners used for in hospitals
they are used to detect infrared radiation emitted from hot spots on the body surface, these hot areas can mean the tissues underneath in not healthy
what type of cameras are used to see things in the dark
infrared cameras
what does infrared radiation do to objects and what are the uses of this
it heats them up- this is used in electric heaters that emit infrared radiation to quickly warm up rooms and electric cookers that emit more infrared radiation then ordinary ones
what is the wavelength of microwaves like in comparison to radio waves
shorter
what are the uses of microwaves
communication e.g. satellite TV and mobile phone signals
why does microwaves ovens heat food faster than ordinary ovens
the microwaves can penetrate into food and are absorbed by the water molecules in the food, heating it.
what do radio wave frequencies range from
300,000Hz to 3000 million Hz
what are radio waves used for
to carry radio, TV and mobile phone signals
what are the hazarders of radio and microwaves
they penetrate peoples bodies and can heat up internal body parts
what are carrier waves
waves that are used to carry a signal
the shorter the wavelength of the carrier wave the…
more information they carry, the shorter range they have, the less they spread out
what are microwaves used for
satellite phone and TV links and satellite TV broadcasting
