Thermal Physics Flashcards
state two conditions for energy transfer between two objects to take place
- one object must be hotter than the other object, so energy transfer by heating takes place.
- one object exerts a force on the other object, i.e. one object does work on another object.
What is internal energy?
the sum of the random distribution of the kinetic and potential energies of an object’s molecules.
How can the internal energy of an object be increased?
energy transfer by heating the object
work done on the object
What does it mean when the internal energy remains constant?
either no energy is transferred by heating and no work is done.
or energy transfer by heating and work done balance each other out.
What is the first law of thermodynamics?
change of internal energy = total energy transfer due to work done and heating
What is the internal energy of an object at absolute zero temperature?
minimum
What is specific heat capacity?
the energy needed to raise the temperature of unit mass of a substance by 1K without change of state.
What is the inversion tube experiment?
see textbook
How would you measure the specific heat capacity of a metal?
have a block of the metal of known mass m in an insulated container. insert a heater into a hole in the block. insert a thermometer into the block. Can calculate electrical energy supplied to block (IVt). assume no heat loss to surroundings.
How would you measure the specific heat capacity of a liquid?
Place a known mass of the liquid into an insulated calorimeter of known mass and known specific heat capacity. place a heater into the liquid. Insert a thermometer into the liquid. electrical energy supplied = IVt. assume no heat loss to surroundings.
What is the latent heat of fusion?
the energy needed to melt a solid at its melting point WITHOUT A CHANGE IN TEMPERATURE
What is the latent heat of vaporisation?
the energy needed to vaporise a liquid WITHOUT A CHANGE IN TEMPERATURE
What is the specific latent heat of fusion?
the energy needed to change the state of unit mass of a substance from solid to liquid WITHOUT CHANGE OF TEMPERATURE
What is the specific latent heat of vaporisation?
the energy needed to change the state of unit mass of a substance from liquid to vapour WITHOUT CHANGE OF TEMPERATURE
