particles emitted from nucleus large atoms
2 protons, 2 neutrons
charge +2
am 4
move relatively slow
helium atom
emmited from nucleus of atom
single electron leaving
moves faster
high energy electron
charge 1
almost no mass
electromagnetic wave released from nucleas
moves at speed of light
turning a nuetral atom into an ion
atom becomes charged
alpha  best
gamma  worst
the time is takes for half the number of radioactive particles on a sample to decay particles
when radioactive sources give out radiation, they decay
the number of radioactive particles decreases
the splitting of atomic nuclei and is used in nuclear reactors as heat energy.
absorbs a neutron to split
chain reactions
the joining of two atomic nuclei to form a larger one
Mass number (p+n) Nucleons
 A
X
 Z
atomic number, no. of electrons or protons
Same atomic number
diff mass number
close to true value
more repeats give a more accurate
little variation between readings
highly repeatable
gradient= y1 y2

x1x2
Rise distance
 =  = speed
run time
Scalar = have only size
e.g distance, speed
Vector = size and direction
e.g displacement, velocity
A = change in velocity

time
initial velocity  U
change in V V  U
 = 
time time
V = U + AT
Distance time
diagonal line  constant speed
accel 0
gradient  speed
straight line  stationary
Speed time
diagonal line  constant acceleration
straight line  constant speed
Speed
avs = distance moved
time taken
Velocity
V = dm in stated direction
time taken
Acceleration
acc = change in V
time taken for change
V = u + at
S = ut + 1 a + 2
_
2
V2 = U2 + 2as
S = 1 ( u + v )

2
S  displacement
U  initial velocity
V  final velocity
A  constant value of the acceleration
T  time
F = KX
f  force applied
x  extension or compression
k  force constant, the force need to produce a unit extension, k tells us the stiffness of the spring.
The amount a spring stretches is proportional to the force applied
Centripical Force  fc
Centripical acceleration  ac
v 2
ac = 
r
F = mv2
r
v = d = 2πr
t t
The Moment describes the turning effect of force around a fixed pivot
Moment = Force x Distance
Nm = N x M
Torque = F x perpendicular distance
Work = F x linear distance
P
M = mass x Velocity
p = mv
p  kg ms1
m  kg
v  ms1
Momentum is a vector quantity
direction same as velocity
Force  change in momentum
change in time
change im momentum
( F x change in time) = change( mv)
1st  object in motion will remain in motion unless acted apon by another force
2nd  the rate of change in momentum is equal to the force applied
3rd  every reaction has an equal or opposite reaction
energy, ability to do work  Joules, J
power, ability to produce work in a short span of time
p= w
t
angle involved  w = f cos q
q  angle
kinetic energy Ek= 0.5mv2
gravitational poten energy Ep= mgh
micro  x10 6
milli  x10 3
centi  x10 2
mega  x10xp6
kilo  x10xp3
the amount of mass in a certain space, measured in g/cm3
D = M/V
E=M/V  g/cm3
solids  P = F/A
liquids  P = heg
h  height
e  density
g  gravity, 9.81 Nkg
unit  Pascals, Pa
solid to gas  add energy
gas to solid  remove energy
Thermal physics
speed of light \ speed of sound
/
solid to gas  Sublemation
the average speed of the particles
 diff metals are twisted together
 metals are heated, small current produced
 ↑ current, ↑ temp
relies on fact that diff metals expand at diff rates as they warm up
by bonding two metals together you can make a simple electric controller that can withstand fairly high temps
records temp over long periods of time
pen on bimetallic strip records temp on rotating drum
A camera like device that measures
the amount of radiant energy given off by an object
Pressure is Inversely proportional to volume
P x 1/V
V = 1/P
for a fixed mass of gas the pressure is inversely proportional to the volume at a constant temperature
PV a constant
P1 x V1 = P2 x V2
1  initial
2  final
Charle Law( The pressure Law)  the volume or pressure of a final mass of gas, is proportional to the absolute temperature
P1V1 = P2V2
T1 T2
T  degrees Kelvin (+273 to convert)
the amount of energy needed to raise the temp of 1kg of a substance by 1c
E = M x C x change in T
E  energy transferred
M  mass
C  specific heat capacity
T  Change in temp, Ft  It
↑ volume, ↑ heat capacity
small volumes  faster heating and cooling
↑ specific heat capacity gets hotter slower
↓ shc gets hotter faster
C = E / M x chan T = J/kg
is the heat required to melt a solid OR evaporate a liquid
E = mass x SPLH
Types:
Latent heat fusion = energy required to melt a solid
Latent heat of vaporisation = energy required to turn a liquid from a gas
change in size (length, area, volume) of a material in response to a change in temp
 particles vibrate faster with heat and it pushes the particles further apart hence increasing the size of the object
Solids  usually retain thier shape so are best described by a linear coefficient of thermal expansion
Liquids  as the bonds between particles in a liq are not stiff as those in solids, liquids expand more for a given temp rise
Gases  there are no bonds between particles in a gas and so small change in temp can result in a larger change in volume
they all carry energy from one place to another
they involve some sort of oscillation
Wavelength = lamder, speed of the wave
amplitude = volume, how much energy been given
↓
the maximum distance a point moves from its rest position
Frequency  number of waves passing per second , Hertz, Hz
V = F x Lamda
f  frequency
oscillation and propagation are parallel to each other
when waves pass through gaps
gap is equal to wavelength, if the gap is too large most of the energy gets through, but most of waves pass straight through so diffraction is ineffective
A pattern of bands where waves reinforce each other or cancel each other out
 can be used to test if something is a wave or a particle
 waves slow down in shallow water
 straight lines are called wave fronts
 the frequency of the wave doesn't change
the wavelength is decreasing
Snells law
n1sin©1 = n2sin©2
©  angle of incident
n  refractive index
when light is passing from some medium, glass or water, with ri into water  Sin C = 1/n
Sin C = nr/n1
nr  refractive index of medium light is passing into
n1  refractive index of medium light is in