Physics CT3 Flashcards
define amplitude
the maximum displacement of a wave particle from equilibrium
define wavelength
the distance between one crest/trough to the next one
define frequency
how many waves pass ever second
define speed
how fast a wave travels
define time period
the length of time it takes for one wave to pass a point
define a transverse wave
the oscillations are perpendicular to the waves direction of travel.
define a longitudinal wave
the oscillations are parallel to the waves direction of travel
define displacement
a measure of distance in a given direction from point to point
define compression
regions where particles are close together
define rarefraction
regions where particles are further apart
define oscillation
describes the movement and vibrations of particles back and forth
calculation for velocity
frequency x wavelength
define refraction
the change in speed that causes the light to change direction
define interface
the line between two serfaces
define the normal
-line 90 degrees to the interface
-shown as a dotted line
define the ray of incidence
the ray that is going in
define the ray of refraction
the ray that bends
what happens to the direction of the wave when is slows down
it is refracted towards the normal
what happens to the direction of the wave when it speeds up
it is refracted away from the normal
why do prescription glasses refract the light
it bends the light so people can see as the light is then focused
what is the order of the electromagnetic wave spectrum
g-r
-gamma
-x rays
-ultra violet
-visible light
-infrared
-microwaves
-radio`
when will heat stop spreading from high temperature materials to lower temperature materials
until it reaches thermal equilibrium
define thermal equilibrium
if the heat absorbed each second by an object matches the heat emitted per second by an object
what happens if the object is really hot
radiate more wavelengths and higher frequency wavelength
how much energy do emag waves transfer when they have a high frequency
lLOTS
what are shorter wavelength emag waves used for
to sterilise- to kill bacteria cells- things (food, surgical instruments, toothbrushes)
what are gamma rays used for
destroy cancerous cells in the body and to sterilise food and surgical equipment
define tracer solution
a liquid containing a gamma -emitting isotope- is injected into the body
What is the law of refelction
the angle of reflection is equal to the angle of incidence
what are the key points of the refraction practicle
-draw normal
-mark path of ray in and out of block with crosses
-join up the crosses with straight lines
-measure angles from normal to ray
define diffuse reflection
when materials have rough surfaces so the reflected light is scattered in all directions
define specular reflection
when smooth surfaces reflect the light evenly
define white light
it is a mixture of different colours that our eyes see as white
what happens to the wavelength when there is an increase in temperature
it gets shorter
define the power
the amount of energy transferred in a certain time
how much radiation does the earths surface absorb from the sun
around half
what type of radiation does the earth re radiate the sun energy to
infrared radiation
what does the earth do to make sure it stays the same temperature
it must radiate energy into space at the same average rate is is absorbed
