Energy 4.0 / 5 based on 1 rating ? PhysicsEnergyIGCSEEdexcel Created by: Carys GerardCreated on: 06-04-13 11:57 When is energy wasted? When it escapes from a closed system 1 of 24 What is the equation for efficiency? Useful energy output / total energy input 2 of 24 What's the Law of Conservation of Energy? Energy is converted from one form to the other 3 of 24 What is thermal conduction? Transfer of heat energy through a substance's molecules via collision of particles 4 of 24 Why does conduction occur faster in metals? The electrons are free to move and carry energy much more quickly 5 of 24 What is thermal convection? Transfer of heat energy through fluids by the upward movement of less dense regions in the fluid. 6 of 24 Why do liquids expand when they are heated? The particles move faster, and start to break the bonds between molecules before they change state (to gas) 7 of 24 What is thermal radiation? The transfer of heat energy via infrared waves 8 of 24 How do you reduce heat transfer by conduction? Use a vacuum (needs matter) , air and water (poor conductors) 9 of 24 How do you reduce heat transfer by convection? Use a vacuum or a trapped gas or liquid (restricts circulation) 10 of 24 How do you reduce heat transfer by radiation? Use shiny surfaces (reflect radiation and poor radiators of heat) 11 of 24 What is the equation for work? Work, J = force, N x distance, m 12 of 24 What is the equation for GPE? GPE, J = mass, kg x g, N/kg x height, m 13 of 24 What is the equation for weight? Weight, N = mass, kg x g, N/kg 14 of 24 What is GPE converted to when work is done on an object? Kinetic Energy 15 of 24 What is the equation for KE? KE, J = 0.5 x mass, kg x speed², m/s 16 of 24 What is the equation for power? Power, W = work done, J / time, s 17 of 24 What can 1 watt also equal? 1 joule / second 18 of 24 What is geothermal energy? Energy produced by the heat of the Earth's core. It is renewable. 19 of 24 What is solar energy? Photovoltaic cells are used to convert light energy into electricity. It is renewable. 20 of 24 What are fossil fuels? Oil, gas and coal. They are non renewable. 21 of 24 What is hydroelectricity? The GPE of water to electricity. It is renewable. 22 of 24 What is tidal power? Harnessing of KE of tides in the sea. It is renewable. 23 of 24 What is wind power? Wind's KE into electricity. It is renewable. 24 of 24
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