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Description
Flashcards by Jessie Howes, updated more than 1 year ago
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Created by Jessie Howes
almost 7 years ago
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| Question | Answer |
| Name 8 types of energy | 1.Gravitational potential 2.Elastic potential 3.Heat 4.Light 5.Electric 6.Nuclear 7. Kinetic 8. Sound |
| Name 3 ways energy can be transferred | 1. Mechanically (force doing work) 2.By heating 3. By radiation (i.e Light, or sound) |
| What is a system? | A term used to describe the object (or group of objects) you are interested in |
| What happens when a system changes? | Energy is transferred. It can be transferred into or away from the system, or between different types of energy stores. |
| What is a closed system? | A system where neither energy or matter can enter or leave. The net change in energy is always 0. |
| Explain how energy is transferred when boiling a kettle | Energy is transferred electronically to the thermal energy store of the kettle's heating element. Energy is then transferred by heating to the water's thermal energy store. |
| What word can be used to describe both: - When a current flows (against resistance) -A force moving an object | Work |
| Explain how energy is transferred when a ball being dropped from a height. | The gravitational force does work, as it is accelerated by gravity. Energy is transferred from the ball's gravitational potential store to its kinetic energy store. |
| When an object slows down, is energy transferred to or away from its kinetic energy store? | Away |
| If a moving object has a large mass, will it have more or less energy in its kinetic energy store than a lighter object moving at the same speed? | More |
| What is the formula for working out the kinetic energy store? | E=1/2mv^2 Kinetic Energy (J) = 1/2 x mass (kg) x (speed)^2 ((m/s)^2) |
| True or False: The higher you lift an object, the more energy it has in its gravitational potential store? | True |
| What is the formula for working out the g.p.e store? | E=mgh g.p.e (J) = mass (kg) x gravitational field strength (N/kg) x Height (m) |
| What's the formula for working out the elastic potential store? | E=1/2ke^2 Elastic Potential (J)=1/2 x Spring constant (N/m) x extension^2 (m) |
| What is specific heat capacity? | The amount of energy needed to raise the temperature of 1kg of a substance by 1C |
| What's the formula that links energy transferred to specific heat capacity? | Change in E=mc x Change in temp Change in thermal energy (J)= mass (kg) x specific heat capacity (J/kg/C) x Change in temp |
| What is the conservation of energy principle? | Energy can be transferred usefully, stores or dissipated, but can never be created or destroyed |
| What is power? | The rate of energy transfer or rate of doing work |
| What are the two formulas for working out power? | 1. P=E/t Power (W) = Energy Transferred (J) /Time (s) 2. P=W/t Power (W)= Work done (J)/ time (s) |
| Define Conduction | The process where vibrating particles transfer energy to neighbouring particles |
| Where does conduction happen? | In solids |
| Explain how conduction occurs | Energy transferred into an object by heating is transferred into the kinetic energy stores of the particles in the object. The heated particles vibrate more and collide with each other, causing energy to be transferred between particle's kinetic stores |
| What is thermal conductivity? | A measure of how quickly energy is transferred through a material via conduction |
| What is convection? | Convection is where energetic particles move away from hotter to cooler regions |
| Where does convection occur? | In liquids or gases |
| How does convection work? | In liquids and gases, particles can move. When you hat a region, the particles move faster and the space between particles increases. This causes the density to decrease. Because liquids and gases can flow, the less dense region rises above the denser, cooler regions. If there is a constant heat source, this creates a convection current. |
| Explain how a radiator uses convection currents to heat a room? | Energy is transferred from the radiator to nearby air particles by conduction as they collide. Air particles nearby become heated and the air becomes warmer and less dense. Warm air rises and is replaced by cooler air, which is heated by the radiator Simultaneously, the previously heated air becomes more dense, and sinks as it transfers energy to the surroundings The cycle repeats |
| How do lubricants reduce frictional forces between two objects? | They are liquids, so can flow between the objects, coating them. |
| Give 3 examples of thermal insulation in a house? | 1. Cavity walls (air gap reduces conduction) 2. Loft insulation reduces conduction currents in loft 3.Double glazed windows (air gap reduces conduction) 4. Draught excluders around doors and windows (reduces convection) |
| What is the equation for working out the efficiency of energy transfer? | Efficiency= useful output energy transfer/total energy transfer |
| What is the equation for working out the efficiency using power input? | Efficiency = useful power output / total power input |
| What are the 3 fossil fuels? | 1. Coal 2.Oil 3. (Natural) gas |
| Give to cons of fossil fuels? | 1. Will run out one day (non-renewable) 2. Damages the environment |
| Name 7 renewable energy sources | 1. Solar 2. Wind 3. Water waves 4. Hydro-electricity 5.Bio-fuel 6. Tides 7. Geothermal |
| What are two pros about renewable energy? | 1. Doesn't damage the environment as much as non-renewable 2. Will never run out (renewable) |
| What are two cons of renewable energy? | 1. Not as reliable (some depend on weather) 2. Don't provide as much energy |
| What are 3 pros of wind turbines? | 1. No pollution 2. No fuel costs 3. Minimal running costs 4. No permanent damage to landscape |
| What are 4 cons of wind turbines? | 1. Spoil the view 2. You need lots (1500 wind turbines = 1 coal fired power station) 3. Can be very noisy 4. Depends on wind 5.Impossible to increase supply when there's extra demand 6. Initial costs are quite high |
| Name some pros of solar cells | 1. Can be used in remote places 2. No pollution 3. Very reliable in sunny countries, but can be cost effective in cloudy countries too 4.Energy is free and running costs are almost nothing |
| Name some cons of solar cells | 1.Use a lot of energy in while being made 2.Can't increase power output when there's extra demand 3. High initial costs4. Generate electricity on a small scale |
| Name some pros of geothermal energy | 1. Reliable 2. Does little damage to the environment 3. Free energy |
| Name some cons of geothermal energy | 1. Not many suitable locations (have to be volcanic) 2.Cost of building a power plant is high compared to amount of energy |
| Name some pros of hydro-electric power | 1. No pollution 2. Immediate response to sudden demand for electricity 3.Reliable except in time of drought 4.No fuel and minimal running costs |
| Name some cons of hydro-electric power | 1. Big impact on environment (rotting vegetation releases methane and CO2, loss of habitat) 2. Look ugly once dried up 3. Initial costs are high |
| Name some pros of wave power | 1. No pollution 2. No fuel and minimal running costs 3. Useful on small islands |
| Name some cons of wave power | 1. Disturb the seabed 2. Loss of marine habitats 3. Spoiling the view 4. Hazard to boats 5. Unreliable (no wind= no waves) 6.High initial costs 7.Not likely to be used on a large scale |
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