test 1
types of waves
transverse (long waves (water) that travel perpendicular, back and forth and primarily vertically)
longitudinal (dots (sound waves) travel parallel, primarily horizontal)
what is frequency
amount of waves per second (how often) (1/period of one wave)
what are transverse waves
waves that look similar to waves of water that travel perpendicular and go back and forth (though they travel vertically)
what are longitudinal waves
waves like sound waves that are parallel to the energy that contain compressions (particles close) and refractions (particles spread)
what is one wavelength
the point of one wave to the same point of the next wave
what is frequency
the amount of waves per second
what is the period
how long something takes to occur
what is wavelength measured in
metres
what is amplitude
the high of the disturbance
equation for frequency
F=1/T
what is T
period in seconds
what is frequency measured in
Hertz of Hz
where should you use when finding wavelength
the cress (top) or troph (bottom) of the wave
what is the funny greek symbol in waves
wavelength (thembda or smt)
how do you find the velocity of the waves
V=FWavelength
what is the speed of light
3 x 10 to the power of 8 (ms-1)
what is the speed of sound
343ms-1
is velocity fixed?
yessir, unless there is a change in medium
increasing order in frequency within electromagnetic spectrum
radio
microwaves
infra red
visible
UV
(E beams)
X rays
Gamma rays
how is the electromagnetic spectrum formed
charged particles
is light a particle or a wave
both!
how is light both?
light can interact like a particles but also appears as a wave and is able to cross other rays (idk)
what is the normal
a line perpendicular to the line in which the light is refracting/deflecting/diffusing
how is the velocity/wavelength affected when entering a denser medium
it descreases
angle of incedence meaning
the angle between the ray entering the new medium and the normal
angle of reflection meaning
the angle between the ray thats been reflected and the normal
how does the speed of light change when entering denser mediums
it decreases
what is the refractive index
the ratio of how much light is slower
what is the equation for refractuve index
n=c(3x10^8)/v(speed of light in medium)
what is the equation of snells law
n1sin~1=n2sin~2
why does dispersion occur
due to the difference in wavelengths between each colour, they are split up as the different wavlengths provide different bending (red longest)
this is due to a difference in speed between the different wavelengths because velocity is fixed
does disperison support the wave or particle model for light
wave as dispersion is dependant on having different wavelengths for each colour
how does a mirage occur
the more dense air above the ground which is cool as cool air falls has the light go through it, then through the least dense media as the air closest to the ground is extremely hot, this is then put at the correct angle, creating TIR which reflects the sky on the ground, creating the look of water
what is the law of reflection
the angle of incendence is the same as the angle of reglection
why does diffusion occur
when wavefronts meet irregular, rough surfaces
what diffusion
when waves spread over a broad area and each pount reflects a portion of the wavefront in diff directions
transparent meaning
ALL light goes through
translucent meaning
some light passes through
opaque meaning
no light passes through
refraction is what
the change in direction of light caused by change in speed
when does refraction occur
when light passes into new medium
what is polarisation
when some light is blocked (roughly 50%
is stackable
does polaristion support light as a wave or particle
supports concept of light as a wave as light travels in all directions if unpolarised
rule for light passing through slits/filters
the light of the same plane can travel through slits of the same angle (vertical and vertical) (all other is blocked)
what is uncertainty
half of the smalled measurement that the equipment is able to take
what is internal energy (IE)
the three main energies for particles in a substance summed together (TKE +RKE +PE)
what is TKE
translational kinetic energy which is the motion inside the substance (higher speed =more KE)
what is RKE
doesnt matter!!!
what is PE
potential enrgy is the attractive/replusive force between particles
how do you change type of substance (solid -> liquid etc)
add energy
what else is IE called
thermal energy
what unit is used for energy
joules (J)
is temp related to PE particles
nope
what is Kelvin
the measurement if temperature defined as absolute zero
what is absolute zero and how do you change Kelvin to Celsius
-273 C
this means that K=C+273
are the size of the unit used in K and C the same?
yep
when is degree used
in C and F (not used in physics)
what is thermal equilibrium
when heat spreads through the substance to even out
how does thermal equilibrium relate to kinetic energy
there is no net transfer of kinetic energy betreen two bodies within thermal equilibrium (thus 0 work)
what is the Zeroth law of thermodynamics
if A is in thermal equilibrium with B and B is in TE with C, then A must be in TE with C
what is the first law of thermodynamics
the change in Internal Energy = heat added to the system (any enclosed object) minus the work done by system
triangleU =Q-W
is Q>O in the first law of thermodynamic, then what?
the net flow is into the system
if W>0 in the first law then what?
the work is done by the system (if less than, work is done on the system)
what is the kinetic particle model
the concept that the small particles that make up all matter have kinetic energy (all must therefore be in constant motion)
how do particles act in a solid
must be exerting attractive/ replusive forces/bonds on each other for matter to hold shape
how do particles act in liquids
a balance of attractive and repulsive forces
more freedom of movement
particles collide remain attracted
how do particles act in gases
particles are in constant, random motion, meaning they are colliding w/ each other and walls
what is specific heat capacity
the amount of energy required to raise the temp of 1kg bt 1C
what is the equation for specific heat capacity
change in energy (triangle E in Joules)=mass (m) x specific heat capacity (c in j/kg C) x temp change (triangle theda in C)
what is the equation for heat transfer
Q (heat transfer) = m (mass) x c (shc (j/kg K) x triangleT (K)
if higher heat capacity
takes longer to heat up/cool down (water is very high)
what is latent heat
the increase of energy may change the state of a substance, but not the temp of a substabce
do gas burns do more damage than water burns at same temp
yes, therefore increase in energy is more intense, not necessarily just temp
what is temperature
the movement of particles, not the amount of energy it has
why doesnt temperature change in state change
the energy that is added us used to increase the potential energy, making the partickes move faster and be able to break free, causing melting or boiling
this means the energy supplied is not used for kinetic energy, but to break the bonds
equation for latent heat
Q (latent heat in J) = m (mass) x c (specific heat capacity (Jkg-1))
what is the latent heat of fusion
the latent heat of melting or freezing (solid to liquid and vice versa)
what is the latent heat of vapourisation
the latent heat required for evaporating or condensing (liquid to gas and vice versa)
how does evaporation occur
when high translational kinetic energy particles in liquid escape from the surface and form gas (doesnt boil)
may be assisted by substance being at high temp and wind
what does evaporation leave
the lower TKE partickes, meaning the remaining substance is at a lower temperature
what is heat conduction
the transfer of thermal energy without net transfer of matter
what causes head transfer
vibrating particles colliding with adjacent particles
what affects heat conduction
temperature difference (greater temp diff means greater rate of transfer)
shape as greater cross sectional area means greater transfer but greater length or width means slower
material as freedom of particles but close together means good conductor and when particles too close together or too far apart they are bad conductors
if a good absorber
good emitter
what is convection
heat transfer through movement of fluids or gasses
shown clearly through hot air rising and cool are falling and creating a cycle
what is radiation
heat transfer through electromagnetic waves (light or non visible) emitted by moving charged particles (hot objects =fast vibrating =high frequency radiation)
how can radiation move
transmission
reflection
absorber
what is absorbtion for radiation
the energy of matter increases so object gets hotter
what are good absorbers in radiation
coliurs that absorb more frequencies of light (black)
what are bad absorbers of radiation
reflective colours (shiny stuff and white)
all objects with a temp above 0 Kelvin emit what
a range of frequencies of radiation because partickes move with a range of speeds (hotter =emit more overall/higher) proportion of gigh frequency radiation)
what is wiens law
the wavelength of radiation is inversely proportional to the temperature of an object
what is the equation of wiens law
wavelength max T =2.898 x 10^-3 mK
wavelength max or peak wavelength is the wavelength that is emitted the most!
when does TIR occur
when the angle of incidence is greater than the critical angle, meaning there is a higher index of refraction in the first medium as light travels
what must the angle of refraction be for TIR
it must be 90, meaning the angle from the normal in the second medium must be 90 opposite from the angle of incidence
what is the equation for the critical angle
angle of crit =sin-1(n2(sin90)/n1)
this is because the angle of refraction (n2) must be 90, and the crit angle is still in the first medium (n1
how do mirages form simple
less dense air higher as hot air rises and the least dense air at the floor as the ground heats the air up, this means that the light is travelling from less dense media in the air when it hits the ground, causing TIR at the correct angle, this then displays the sky as it reflects off of the ground
what are black bodies
models that represent something as being much more equal and generalised by decreasing the compoexity and inconsistency
black bodies are
perfect emitters and absorbers of radiation