P 2 energy transfer by conduction Flashcards
best conductor
metals
how does thermal conductivity impact energy transferred by conduction
the greater it is the more energy per second it transfers by conduction
characteristics of insulators
low thermal conductivity
parts of electromagnetic spectrum
infrared radiation and visible lights
what does every body do (radiation)
give out/ emit infrared radiation and absorb them
what is a perfect black body
absorbs all the radiation that hits me
best possible emitter
how does intensity of a balck body change
varies with wavelenght
intensity is highest at certain wavelenght that depends on temp
what happen if an objexct has constant temp.
emits infrared radiation at same rate it absorbs it
what does temp of earth depend on
absorption of infrared radiation from gases
emission of radiation from eaths’s surface and atmosphere
specific heat capacity
energy needed to raise temp of 1 kg of the substance by 1 c
temperature rise when an object is heated depends on
en. supplied to it
mass of substance
what substance it is
how to reduce rate of energy transfer from a home
loft insulation
cavity wall
aluminium foil between a radiator panel and wall
double-glazed windows
outside walls thicker bricks
what is direct potential difference
polarity doesn’t change
one direction only
