4039003
Description
Flashcards by gizmoalex123, updated more than 1 year ago
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Created by gizmoalex123
over 8 years ago
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| Question | Answer |
| Infrared Radiation | Energy transfer by electromagnetic waves |
| Q. Dark, Matt surfaces... | emit more infrared radiation than light, shiny surfaces. they also absorb more infrared radiation than light, shiny surfaces. |
| Solid | fixed shape and volume |
| Liquid | fixed volume but no shape |
| Gas | does not have a fixed volume and can flow |
| What are the best insulators? | Wool and fibreglass |
| Why are non-metals poor conductors? | they do not contain free electrons |
| What is convection? | Convection is the circulation of a fluid (liquid or gas) caused by heating it. Convection takes place in only liquids and gases. |
| What is evaporation? | Evaporation is when a liquid turns into a gas. |
| What is condensation? | Condensation is when a gas turns into a liquid. |
| How could you increase evaporation? | -Increasing the surface area of the liquid -Increasing the liquid's temperature -Creating aa draught of air across the liquid's surface |
| How could you increase condensation on a surface? | -Increase the area of the surface -Reduce the temperature of the surface |
| What does the rate of energy transferred to or from an object depend on? | -The shape size and type of material of the object. -The materials the object is in contact with. -The temperature difference between the object and it's surroundings. |
| Energy transfer equation | Energy transferred in joules (J)=mass in kilograms (kg) x specific heat capacity J/kg °C x temperature in degrees celcius (°C) E= m x c x θ |
| Rearrange the previous equation to find the specific heat capacity of something | c = E ÷ m x θ |
| Q. The greater the mass of an object... | The more slowly it's temperature increases when it is heated |
| What does the rate of temperature change of a substance when it is heated depend on? | -The energy supplied to it -it's mass -it's specific heat capacity |
| U-values | U-values tell us how much energy per second passes through different materials |
| Q. The lower the U-value... | the more effective the material is as an insulator. |
| How can energy transfer from our homes be reduced? | By fitting: -Loft insulation -Cavity wall insulation -Double glazing -Draught proofing -Aluminium foil behind radiators |
| Q. Cavity wall insulation reduces the rate of energy transfer due to... | Radiation |
| Q. Aluminium foil behind a radiator reduces the rate of energy transfer due to... | Convection |
| Q. Closing the curtains in the winter reduces the rate of energy transfer due to | Convection and Radiation |
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