Physics Unit 1 and 2

• Temperature is a measure of the average kinetic energy of particles inside the substance
• Amount of energy increase in substance depends on:

  1. Mass
  2. Specific heat capacity
• Specific heat capacity (c) is the amount of energy needed to be transferred to change the temperature of 1kg of material by 1 degree celsius or kelvin
• Latent heat of vapourisation: The amount of energy needed to change a substance from a liquid to a gas/gas to liquid
• Latent heat of fusion: The amount of energy needed to change a substance from solid to liquid/liquid to solid
• Evaporation: The change of state of a substance from liquid to gas at room temperature
• The 4 laws of thermodynamics:

  0. If object A and B are in thermal equilibrium with object C, they must also be in thermal equilibrium with each other

  1. The conservation of energy (heat gained = heat lost)
  2. Entropy of a system increases with time
  3. The entropy of a pure crystalline substance approaches zero as temperature approaches absolute zero
• define heat


  transfer of thermal energy from a hot to colder body
• what happens as temperature of substance increases?

  average kinetic energy of substance increases, therefore particles move faster
• What does it mean when only potential energy increases and not kinetic energy?

  Heating results in a change of state or expansion, not a change in temperature
• Potential energy


  stored energy
• Kinetic energy


  energy of movement
• Internal energy/thermal energy

  sum of kinetic and potential energy of particles within a substance
• Temperature

  a measure of the average amount of kinetic energy within a substance
• Formula for Latent heat

  Change in potential energy=mass * specific latent heat
• Formula for specific heat

  Change in energy = mass * specific heat capacity * Change in temperature
• define convection


  transfer of energy within a fluid by mass movement of energetic particles from one place to another
• define conduction

  the process where energy is transferred from one substance to another without the net movement of particles
• assumptions of the kinetic particle theory

  1. all matter is made up of particles
  2. particles are in constant motion
  3. kinetic energy is not lost during collisions between particles
  4. there are repulsive and attractive forces between particles
  5. the distance between gas-particles are large compared to their size
• explain why the temperature of the system remains the same during the process of state change in terms of the internal energy of a system and the kinetic particle model of matter

  During state change, the temperature remains constant because when energy is added, particles do move farther apart but do not move faster, weakening intermolecular forces. The energy gets stored as potential energy while the kinetic energy stays the same, and therefore temperature also stays the same
• How to convert Celsius to Kelvin

  +273.15
• Kelvin to celsius

  -273.15
• Density formula

  Mass/volume
• define radiation

  transfer of kinetic energy through electromagnetic waves without the mass movement of particles
• Compare an Arbitrary and Absolute scale

  Absolute scales have a defined minimum value, and can only progress in one direction. Arbitrary scales begins at one value and can progress in both directions
• All temperature, colour, and surface nature will affect the rate at which an object radiates thermal energy
• analogue scale uncertainty

  half of smallest increment
• digital scale uncertainty

  smallest increment
• Uncertainty propagation: addition and subtration

  Add absolute uncertainties
• Uncertainty propagation: multiplication and division

  add percentage absolute uncertainty
• density is mass/volume
• speed of light^2 (c^2) in MeV = 931.6MeV
• Mass defect = mass of reactants - mass of products
• Energy change = Mass defect * speed of light^2
• Energy released in beta negative decay = (parent nucleus mass - daughter nucleus mass)*931.6
• Energy released in beta positive decay = (parent nucleus mass - daughter nucleus mass - two mass of electron)
• energy release in gamma decay = 0
• Kinetic particle model of matter


  A model that describes matter as composed of small particles in constant motion.
• Thermal energy


  The total kinetic and potential energy of the particles in a substance.
• Temperature


  A measure of the average kinetic energy of the particles in a substance.