p6 waves Flashcards
mechanical wave
waves that involve particles moving, or oscillating e.g sound waves
electromagnetic waves
waves that don’t involve any particles oscillating, instead they involve vibrations
transverse wave
oscillations are perpendicular to the direction of ebergy transfer
longitudinal waves
oscillation are parallel to the direction of energy transfer, showing areas of compression and rarefaction
what type of wave are electromagnetic
transverse waves
what is a wave
carries energy from one place to another, and can also carry information. They involve oscillations, allowing energy to be transferred without having to flow or travel from one place to another
oscillations
vibrations or movements
perpendicular
at right angles to
amplitude
maximum displacement of a point on the wave from the undisturbed position
wavelength
the distance from a point on one wave to the equivalent point on the next wave along
frequency
number of complete waves that pass a point per second
period
time period of a wave is the time it takes to complete a full wave
an absorber
an object which absorbs the wave
what do all electromagnetic waves do
travel at the same velocity through a vacuum (empty space)
which electromagnetic wave has the longest wavelength
radio waves
which electromagnetic wave has the shortest wavelength
gamma rays
which electromagnetic wave has the lowest frequency
radio waves
which electromagnetic wave has the highest frequency
gamma rays
properties of electromagnetic waves
can be reflected, refracted, absorbed or transmitted
when does refraction occur
when a wave changed the medium it is travelling through,
refraction
change in direction of a wave due to a change in the medium it is travelling through
reflection
rebouding a wave from a surface. The angle between the incident ( in-going ) and the normal is the same as the angle between the reflected wave and the normal
absorption
taking in energy from a wave and transferring it to another form, usually heat
transmission
a wave travelling through a material e.g visible light waves transmitted through the air to your eyes
media
singular medium
normal
a construction line at right angle to a surface at the point where the wave hits the surface
how are electromagnetic waves generated
by changes in atoms.
how are radio waves produced
by oscillation on electrical circuits. The radio waves create an alternating current with the same frequency as the radio wave itself
what waves are dangerous to human tissue
UV waves, X-rays and gamma rays (how severe the effects are depends on the type of radiation and the dose received)
how is a dose of radiation measured
according to how great the risk of harm on the human body is
radiation dose
risk of harm due to exposure to radiation
exposure
recieving and absorbing radiation by the body
slevert
the measure of radiation dose
ionising
describes radiation that forms ions by ‘knocking’ electrons off atoms to make ions
cancer
disease caused by mutation to dna, resulting in cells dividing out of control
how are radio waves used
television, radio and bluetooth - a signal carried by radio waves can get from a transmitting mast to a receiver by being reflected off a layer in the atmosphere
how are microwaves used
heat food, communications with satellites - microwaves can pass through the atmosphere.
how are infrared waves used
electrical heaters, certain cameras - All objects emit infrared by hotter object emit more
how is visible light used
fibre optic communication - reflect pulses of light all the way along their length, transmitting information
how are UV waves used
tanning beds
how are x rays used
medical imaging
how are gamma rays used
medical treatments such as radiotherapy
