Question | Answer |
What is specific heat capacity? | A measure of how much energy a substance can store: The amount of energy needed to raise the temperature of 1kg of a substance by 1 degree celcius. |
What is the specific heat capacity of water? | 4200 J/kg/degree c |
What is the unit for specific heat capacity? | J/kg/degrees c |
Why are there flat spots on a heating graph? | Energy is being used to break intermolecular bonds rather than raising the temperature. (melting and boiling) |
What is specific latent heat of melting? | Amount of energy needed to melt 1kg of material withou changing its temperature. (i.e the material has got to be at its melting temperature already) |
What is specific latent heat of boiling? | Energy needed to boil 1kg of material without changing its temperature (i.e the material's got to be at its boiling temperature already) |
What is the unit for specific latent heat? | j/kg |
What is conduction? | Conduction of heat is the process where vibrating particles pass on extra kinetic energy to neighbouring particles. |
What is convection? | Convection occurs when the more energetic particles move from the hotter region to the cooler region - and take their heat energy with them. This is because when you heat up a liquid/gas it expands (particles move faster) meaning it becomes less dense mea |
What uses convection in the home? | Radiators |
Why can't convection happen in solids? | Particles can't move - vibrate on spot |
How do you reduce convection? | Stop the fluid moving. Clothes, blankets and cavity wall foam insulation work by trapping pockets of air. |
In what ways is radiation different from convection and conduction? | 1) Radiation occurs in a vacuum 2) It can only occur through transparent substances. 3) Amount of radiation emmitted absorbed by an eobject depends to a large extent on it's surface colour and texture. |
Why are survival blankets made of shiny material? | it reflects the body heat back inside the blanket and minimises heat radiation being emitted by the blanket. |
What saves energy and money for the home? | Insulation |
how can you insulate your home? | Loft insulation Cavity Walls Draught proofing Hot water tank jacket Double glazing Thick Curtains |
What is used to see where your house is losing heat? | Thermogram |
How does a thermogram work? | Objects at different temperatures emit infrared rays of different wavelengths. Red and yellow show where heat is being lost. |
What is wavelength? | The length of a full cycle of a wave e.g crest to crest. |
What is wave frequency? | The number of complete waves passing a point per second. Measured in Hz |
What are the 7 electromagnetic waves? | Gamma Rays, X rays, Ultraviolet, Visible Light, Infrared, Microwaves, Radiowaves |