Kinetic Theory and Temperature in Gases
Gases are randomly moving particles!
> Very Small Particles
> Constantly Moving
> Collide with eachother all the time
Absolute Zero is as cold as stuff can get - 0 Kelvin
COLDEST EVER = -273 KELVIN
To convert from C to K just add 273. :)
Kinetic Theory is proportional to Temperature
The temperature of a gas (in kelvins) is proportional to:
the average kinetic energy of its particles.
Pressure in Gases
Constant = Pressure ÷ Temperature (in K)
p1/t1 = p2/t2
Particles In Atoms
- HELIUM NUCLEUS
- SLOW AND HEAVY
- STRONGLY IONISING
- STOPPED BY PAPER
- AN ELECTRON
- LIGHT AND FAST
- MODERATELY IONISING
- STOPPED BY THIN METAL
- ELECTROMAGNETIC RADIATION
- NO MASS, VERY FAST
- WEAKLY IONISING
- STOPPED BY THICK LEAD
Different types of Radiation
POSITRON RADIATION= positively charged beta radiation
NEUTRON RADIATION= neutrons - very penetrating!
NEUTRONS ARE DIFFICULT TO DETECT BECAUSE THEY'RE NEUTRAL.
- Charged particles knock electrons off atoms, ionising them.
- LOSS OF ELECTRONS = IONISING
- They also move towards charged objects.
- You can use an electrical field to deflect a beam of alpha particles.
- NONE OF THIS WORK FOR NEUTRONS- they are detected by looking for nuclear decays.
Particles in Atoms
A nucleus will be unstable if it has:
- too many neutrons/too few neutrons
- if its too heavy eg. to many protons and neutrons together
- too much energy
β - ) decay happens when there are too many neutrons, the proton number decreases by one, and the nucleon number stays the same.
β + ) decay happens when there are too few neutrons, the proton number decreases by one, and the nucleon number stays the same.
α ) decay happens in heavy nuclei, the proton number decreases by two, and the nucleon number decreases by four.
γ ) is emitted from a nuclei with too much energy.
Fundamental and Other Particles
Electrons and Positrons are fundamental particles.
This means you can't divide them into smaller particles.
Scientists can recreate fundamental particles by colliding particles at a very high speed. This produces an equal amount of matter and anti-matter made of anti-particles.
Each particle has an anti-particle which has the same mass, but opposite charge.
Protons and Neutrons are NOT fundamental particles.
They're made of quarks!!
Proton = UUD | Neutron = DDU
USED FOR TV SCREENS >>>
- The heater heats the cathode and gives energy to the electrons.
- They're pulled towards the positive anode.
Calculating the kinetic energy of each electron..
kinetic energy (j) = charge of electron (in coulombs) x accelerating voltage (volts)
and, the size of the current produced..
current (l) = charge (n x e) ÷ time (t)
Electron Beams 2
An electron beam is attracted by a positive charge, and repelled by a negative charge.
Electron guns are used in TV's, Oscilloscopes, and to make X-Rays.
An Oscilloscope is a device for displaying the voltage and frequency of an electrical signal.
> = time / ^ = voltage
xrays = tungsten target.