Flashcards in Physics Deck (150)
what is temperature the measure of ?
average KE of particles in a substance
0 kelvin is how many degrees Celsius ?
what is heat measured as ?
what is heat a sum of ?
kinetic energy of all particles
what does increasing distance between particles do to the bonds?
decreases the strength
why does the temp of a substance not increase during melting/boiling ?
additional energy used to break intermolecular bonds
what is latent heat ?
the amount of energy needed to change the state of a substance
name the 4 factors of condensation
temp / surface temp / airflow / density
why is rate of condensation higher with greater density ?
particles closer - stronger forces
what is evaporation ?
liquid changing to a gas without boiling (average KE of particles is below BP)
individual particles only evaporate if ...
- high KE
- travelling towards surface
name the 4 factors of evaporation
temp / airflow / density / surface area
process of vibrating particles passing on their KE to neighbouring particles in a material
why are metals good conductors ?
ions are tightly bound
free electrons can transfer energy
why are non-metals not very good at conducting ?
no free electrons
what is a fluid ?
substance with no fixed shape
what is convection ?
transport of heat energy through a fluid
why does hot air rise ?
less dense due to particles moving further apart from each other
what is the term for the cycle of hot air rising and cold air replacing it ?
what is radiation (heat) ?
heat transfer from the emission of electromagnetic waves from warm bodies
why can radiation travel through space ?
does not require a medium
what is power the rate of ?
rate of energy change
energy / time
what are the best absorbers and emitters of radiation ?
dark matte objects
what are the worst absorbers and emitters of radiation ?
bright and glossy objects
give the factors of heat transfer
SA / vol / material
list the features of a vacuum flask
- vacuum between container and flask
- inside and outside are shiny
- insulating foam
why do warm climate animals have large ears ?
increases SA so can radiate more heat
mass / volume