p2 - energy transfer by heating

anki flashcards imported for the eoy cram

tags column:3

what are the best conductors of energy

metals

what are the best insulators (examples included)

non metals: wool and fibreglass

what does higher thermal conductivity mean

higher rate of energy transfer through an object

thicker layer of insulating material = what

lower rate of energy transfer through it

true or false: all objects absorb and emit infrared radiation

true

the hotter an object the more ------------- it emits

infrared radiation

what is blackbody radiation

radiation emitted by a body that absorbs all the radiation incident on it

when does the temperature of an object increase

if it absorbs more radiation than it emits

what does the earth's temperature depend on

• absorption of IR from the sun
  - emission of radiation from the earth's surface and atmosphere

what is the specific heat capacity definition

the amount of energy needed to change the temperature of 1kg of the substance by 1 degree celsius

specific heat capacity formula

energy transferred = mass x specific heat capacity x temperature change

how can houses be made more efficient

• loft insulation
  - cavity wall insulation
  - double glazed windows
  - aliminium foil behind radiators
  - external walls with thicker bricks and lower thermal conductivity

what is cavity wall insulation

insulation used to fill the cavity between two brick layers of an external house wall