Physics GCSE Unit 1.1 2.0 / 5 based on 1 rating ? PhysicsEnergyGCSEAQA Created by: R ButlerCreated on: 27-03-13 13:52 Where is heat lost through radiation in houses? Walls, windows and roof 1 of 18 Where is heat lost though convection in houses? Doors, windows and roof. 2 of 18 Where is heat lost though conduction in houses? Walls, floor, roof and windows 3 of 18 Why does double glazing reduce heat loss from houses? Because there is air in the cavity between the panes of glass, and air is a poor conductor of heat. 4 of 18 What is cavity wall insulation? Blowing an insulating material into the cavity between the inside wall and the brick wall, which reduces heat loss by conduction and convection. 5 of 18 How does fitting a carpet reduce heat loss? It reduces heat transfer through the floor by conduction 6 of 18 In a vacuum flask, what does the stopper prevent? evaporation and convection 7 of 18 In a vacuum flask, what is the purpose of the vacuum? To minimize heat loss by conduction, evaporation and convection, as there are no particles present. 8 of 18 Why is the inside surface silver in a flask? To reduce heat loss by radiation because silver is a poor absorber and emitter of raditaion. 9 of 18 Which two states can convection take place in? Liquid and gas 10 of 18 Name three factors that effect evaporation Surface area, temperature, draught 11 of 18 What is specific heat capacity? The energy needed to raise the tmperature of 1kg of a substance by 1 degree Centigrade 12 of 18 What is 'payback time'? The amount of time it takes for an appliance to pay for itself 13 of 18 What is a U-value? A measurement of how much energy per second passes through a material. 14 of 18 The lower the U-value... ... the more effective the material is as an insulator 15 of 18 What does a storage heater do? they use off-peak electricity to store energy is special bricks, that have a high heat capacity and release heat over a long period of time. 16 of 18 What is a heat sink? A component that disperses excessive and unwanted heat using a thermal conductor 17 of 18 Which three factors affect heat transfer? surface area and volume, the material from which the object is made, the nature of the surface with which the object is in contact. 18 of 18
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