P13 Flashcards
WHAT ARE THE PURPOSE OF ELECTROMAGNETIC WAVES?
They travel and transfer energy from one source to another
WHAT ARE ELECTROMAGNETIC WAVES?
made up of oscillating electric and magnetic fields
WHAT TYPE OF WAVE ARE ELERCTROMAGNETIC WAVES/
transverse waves
AT WHAT SPEED DO ELECTROMAGENTCI WAVES TRAVEL THROUGH A VACUUM?
3 x 10>8 m/s
LIST THE ELECTROMAGNETIC SPECTRUM
radio-waves
microwaves
infrared waves
visible light waves
ultra violet rays
x- rays
gamma rays
WHAT HAPPENS TO THE PROPERTIES OF THE ELERCTROMAGNETIC WAVES AS THEY DESCENED DOWN SPECTRUM?
Wavelength decreases and frequency increases
GIVE ONE USE OF RADIOWAVES
Used to transmit radio using transmitter and reciever
generated by alternating current
GIVE THE TWO DIFFERENT WAYS MICROWAVES CAN BE DIFFERENTIATED
Absorbed by water molecules
NOT absorbed by water molecules
GIVE THE USES OF MICROWAVES
ones absorbed by water can be used in microwave ovens
ones NOT absorbed can be used in satellite communication
INAFRED WAVES ARE…
emitted from all objects
WHAT DISTIGUISHES HOW MUCH INFARED AN OBJECT EMITS….
how hot the object is
GIVE TWO USES OF INFARED WAVES
-Can be used in cameras to detect animals (infrared cameras)
-Ovens, infrared waves heats metal and metals re emit infrared to cook food
VISIBLE LIGHT IS…
the only waves our eyes can see
WHITE LIGHT IS?
A mixture of all light waves
WHY DO WE SEE COLOURS AS DIFFERENT COLOURS?
Because all colours have different wavelengths therefore reflect off different things
WHEN WE GO RED TO VIOLET WHAT HAPPENS?
Wavelength decrease’s
WHAT IS ULTRAVIOLET GENERATED BY?
The sun
GIVE TWO USES OF ULTRAVIOLET WAVES?
- Security to reveal invisible fingerprints and writing
-Sunbeds for artificial tan
WHAT IS THE DANGER OF ULTRAVIOLET WAVES?
They can be ionising and cause sunburn and skin cancer
WHAT ARE X-RAYS?
X-rays are electromagnetic waves used to make images of bones to check for fractures
HOW ARE X-RAYS USED IN MEDICINE?
pass through soft tissue but absorbed by bones so you can view internal structure
HOW DO WE X-RAY ORGANS?
as organs are soft tissue and do not absorb x- rays we fill it with a contrast medium
HOW ARE X- RAYS DANGEROUS?
they are ionising and can damage living tissue cells when they pass through
HOW ARE GAMM RAYS USED?
- Sterilisation of medical equipment, kill microorganism
-Keep food fresh for longer
HOW DO GAMMA RAYS WORK?
when they travel through substance they knock electrons out of atoms forming positive ions so they can be ionising hence used in radio therapy to kill cells
