AQA A-LEVEL PHYSICS PAPER 2
Internal Energy
The sum of the kinetic energy and the potential energy.
Absolute Zero
0K, -273℃.
Temperature
The measure of the average kinetic energy of the particles within a substance.
Kinetic Energy
E= 3/2 kT
Heat Transfer
The flow of thermal energy from higher temperature to lower temperature.
Thermal Equilibrium
The average kinetic energy of the particles in both are the same, meaning that they have the same
temperature.
There will be a net flow of energy from hot to cold until the objects reach this.
Heating
Net flow of energy from hotter to colder object.
Doing Work
One body exerts a force on the other and causes movement (energy transfer).
First Law of Thermodynamics
Energy can be transferred and transformed, but it cannot be created or destroyed.
ΔU = ΔQ + ΔW
Change in Internal Energy = energy gained by heating + energy lost by work done.
Specific Heat Capacity
the energy required to raise the temperature of 1kg of a substance by 1℃.
Specific Heat Capacity Experiment
Immersion heater. Graph of T against t. Rearrange IVt=mcT. Gradient can be used to calculate c.
Latent Heat
, The heat energy needed to change the state pf a substance at a constant temperature. Q = ml
Latent Heat of Fusion
Solid to Liquid
Latent Heat of Vaporisation
Liquid to Gas
What factors will affect the temperature change of a substance?
• The amount of energy supplied.
• The substance.
• The mass of the substance.
Inversion Tube Experiment
A cardboard tube of length l, has small lead balls of mass m, inside of it. The initial temperature
of the lead shot is measured and the tube is inverted N times. Each time the tube is inverted, the
GPE lost is converted to internal energy, N x mgl.
Therefore, Nmgl = mcΔT.
Electrical Methods
Metal Block - known mass has holes drilled in to put thermometer and 12v heater in. Assuming
all electrical energy is converted to internal, IVt = mcΔT
Liquids - container and liquid will reach thermal equilibrium. Assuming all electrical energy is
converted to internal,
IVt = mcΔT (of the liquid) + mcΔT (of the container).
Heat Capacity (not specific)
The amount of energy required to raise the temperature of that particular substance by 1K.
Constant Heating of a Solid
Below melting point, heat supplied increases the kinetic energy of the molecules.
At the melting point, the molecules are vibrating sufficiently that they are breaking free from
each other. The energy supplied now increases the potential energy so the state change takes
place at constant temperature.
Once all of the substance has melted, the liquid will then increase in temperature once more until
it reaches its boiling point.
Robert Brown
Internal Energy
The sum of the kinetic energy and the potential energy.
Absolute Zero
0K, -273℃.
Temperature
The measure of the average kinetic energy of the particles within a substance.
Kinetic Energy
E= 3/2 kT
Heat Transfer
The flow of thermal energy from higher temperature to lower temperature.
Thermal Equilibrium
The average kinetic energy of the particles in both are the same, meaning that they have the same
temperature.
There will be a net flow of energy from hot to cold until the objects reach this.
Heating
Net flow of energy from hotter to colder object.
Doing Work
One body exerts a force on the other and causes movement (energy transfer).
First Law of Thermodynamics
Energy can be transferred and transformed, but it cannot be created or destroyed.
ΔU = ΔQ + ΔW
Change in Internal Energy = energy gained by heating + energy lost by work done.
Specific Heat Capacity
the energy required to raise the temperature of 1kg of a substance by 1℃.
Specific Heat Capacity Experiment
Immersion heater. Graph of T against t. Rearrange IVt=mcT. Gradient can be used to calculate c.
Latent Heat
, The heat energy needed to change the state pf a substance at a constant temperature. Q = ml
Latent Heat of Fusion
Solid to Liquid
Latent Heat of Vaporisation
Liquid to Gas
What factors will affect the temperature change of a substance?
• The amount of energy supplied.
• The substance.
• The mass of the substance.
Inversion Tube Experiment
A cardboard tube of length l, has small lead balls of mass m, inside of it. The initial temperature
of the lead shot is measured and the tube is inverted N times. Each time the tube is inverted, the
GPE lost is converted to internal energy, N x mgl.
Therefore, Nmgl = mcΔT.
Electrical Methods
Metal Block - known mass has holes drilled in to put thermometer and 12v heater in. Assuming
all electrical energy is converted to internal, IVt = mcΔT
Liquids - container and liquid will reach thermal equilibrium. Assuming all electrical energy is
converted to internal,
IVt = mcΔT (of the liquid) + mcΔT (of the container).
Heat Capacity (not specific)
The amount of energy required to raise the temperature of that particular substance by 1K.
Constant Heating of a Solid
Below melting point, heat supplied increases the kinetic energy of the molecules.
At the melting point, the molecules are vibrating sufficiently that they are breaking free from
each other. The energy supplied now increases the potential energy so the state change takes
place at constant temperature.
Once all of the substance has melted, the liquid will then increase in temperature once more until
it reaches its boiling point.
Robert Brown
