chapter 13 Flashcards
which is the lowest frequency on the em spectrum
radio waves
which is the higest frequency on the em spectrum
gamma
what colours of the spectrum does white light contain
all of them
what colour has the shortest wavelength
violet
what colour has the longest wavelength
red
name 3 uses of light
torches cameras and optical fibres
do all objects give off infrafred radiation even if they are below freezing
yes
name 3 uses of infrared radiation
optical fibres remote controls and ovans
name 3 uses of microwaves
mobile phones microwave oven and sateliite oven
what is the wave length of a radio wave
range from milli meteres to kilometers
name 3 uses of radio waves
radio bluetooth and remote control car
what dangers can infrared pose
skin burns
what dangers can microwaves and radio waves pose
heating internal body parts
what waves can damage eye sight
visible light and infrared
what type of waves fit into the electromagect spectrum
transverse
what are waves in the electromagnectic spectrum
electric and magnetic disturbances thatn that transfer energy (not matter)
as you move from left to right across the electromagnetic spectrum what happens to the waves
the wavelength gets smaller and the frequency gets bigger
what wavelengths can the human eye see
350nm-650nm
what speed to all electromagnetic waves travel at in a vacuum
3x10 8 m/s
what is the equation for wave speed
wavepeed=frequency*wavelength
which has the highest frequency visible light, infrared or uv
uv has the highest frequency
what are uses of uv
uv can be used for security such as bank notes having uv markings
what are the dangers of uv
causing sun burn and damaging eyes
what has a higher wavelength x rays or gamma
x ray
what are the 2 main uses of gamma
killing harmful bacteria in food or surgical tools and cancer treatment
what is the main use of x rays
medical imaging
what is ionisation
when an atom looses an electron
what happens if ionisng happens to living cells
damage cells and potentially cause cancer
what do people who work with radiation wear
saftey film badge that changed colour when exposed to radiation
what is a differnce between uv and visible light
you cant see uv
what can waves transfer
energy and information
what type of waves carry information and how do they do this
carrier waves they does this by varying their amplitude
how do em waves change properties
based on frequency and wavelength
what transfers more energy ? shorter or higher wavelengths
shorter, as the frequency is higher, this means that more waves arrive in more time so more energy can be transfered. The downside to this is that the range is lower due to absorbtion by the atmosphere
which has a higher frequency radio waves or microwaves
microwaves
what can microwaves be used for
satelite communication
what device converts sound into electrical signals and how does it work
microphone coverts sound into electricial singnals, these are then combined with a carrier waves in a transmitter, this creats a radio signal. A reciever then converts the radio waves back into an electric current witn the same frquency as the wave. A speaker then converts this into sound.
are childrens or adults brains more effected by the use of mobile phones
mobile phones use microwaves signals, children have thinner skulls then adults meaning their brains might be more effected by mobile phone use
what are optical fibres and what 2 parts of the em spectrum do they use
optical fibres are thin transparent fibres that are used to transmit signals by infrared and visible light
why are optical fibres secure
signal is contained in fibire not the air
why can optical fibres transfer more enegy then radio waves
optical fibrres uses ligtht which has a shorter wavelength there for higher frqeuency then radio waves meaning it can transfer more information
do x rays of uv have longer wavelengths
uv
what parts of your body block x rays
bones teeth metal inside body
how does an x ray work
they have a film or detected that changes when x rays hit it
how can you x ray soft tissue organs
fill them with a contrast medium that absorbs x rays
how can you cover parts you dont want to x ray
cover them with lead plates
what is a radiation dose
a measure of the damadge done to the body by ionising radiation
what factores effect radiation dose
radiation type time exposed the energy per second absorbed
what is dose measured in
sv
what waves are used in ct scans
x-rays from differnt angles to created a 3d image
