Chapter 2 Flashcards
Thermal Physics
What is thermal energy?
Energy of the molecules of a body
Thermal energy is related to the temperature and state of a substance.
Define vaporisation.
Change of a liquid to a gas
This process occurs when a liquid reaches its boiling point.
What is absolute zero?
Lowest possible temperature: -273°C or 0K
At absolute zero, the motion of atoms theoretically comes to a complete stop.
What is condensation?
Change of a gas to a liquid
This process often occurs when a gas is cooled below its dew point.
Define conduction.
Flow of thermal energy transferred through matter from places of high temperature to places of low temperature without movement of matter as a whole
An example is a metal rod getting hot at one end when the other end is placed in a flame.
What is convection?
Flow of thermal energy through a fluid from places of high temperature to places of low temperature by movement of the fluid itself because of change of density
This process is common in liquids and gases.
What is the unit of temperature measured in degrees Celsius?
Degrees Celsius (°C)
This scale is widely used for everyday temperature measurements.
What is the SI unit of temperature?
Kelvin (K)
A kelvin has the same size as a degree Celsius, but 0°C = 273 K.
Define a molecule.
Combination of atoms
Molecules can consist of two or more atoms bonded together.
What is a particle?
Any small piece of a substance; it could be one ion, electron, atom, or molecule, or billions of them
Particles are the basic building blocks of matter.
What is radiation of thermal energy?
Transfer of thermal energy from one place to another by infrared electromagnetic wave energy
This process does not require a medium and can occur in a vacuum.
How is temperature defined?
A measure of the average kinetic energy of the molecules of a body
Higher temperatures indicate greater molecular motion.
What is specific heat capacity?
Energy needed per unit mass per unit temperature rise
This property varies between different substances.
