Chapter 2: Sustainable Energy

"What are the main types of energy stores?"

"Chemical

"How can energy be transferred between stores?"

"By working and heating"

"What happens when charge flows through a circuit?"

"Work is done and energy is transferred"

"What energy transfer occurs in a motor powered by a battery?"

"Chemical → Electrical → Kinetic"

"What energy transfer occurs in a kettle powered by a battery?"

"Chemical → Electrical → Thermal"

"What does power rating of an appliance show?"

"The power it uses in watts (energy transferred per second)"

"What is the equation for power?"

"P = Energy transferred ÷ time = Work done ÷ time"

"What are the units of power

energy

"What is 1 watt equivalent to?"

"1 joule of energy transferred per second"

"What is a system?"

"An object or group of objects"

"Give an example of energy transfer in a rolling ball hitting a wall."

"Kinetic energy transferred to sound"

"Give an example of energy transfer in a vehicle slowing down."

"Kinetic energy transferred to thermal energy by friction"

"Can energy be created or destroyed?"

"No

"What is wasted energy?"

"Energy dissipated to surroundings in less useful forms"

"How can energy waste be reduced?"

"Lubrication (reduces friction)

"What does higher thermal conductivity mean?"

"Heat travels through the material more easily"

"What type of walls reduce heat loss in buildings?"

"Thick walls with low thermal conductivity"

"What is efficiency?"

"Useful energy output ÷ Total energy input (or Useful power ÷ Total power)"

"How can efficiency be improved?"

"Reducing waste output (insulation

"What are Sankey diagrams used for?"

"To show energy transfers and efficiency of a system"

"What are the main non-renewable energy sources?"

"Fossil fuels (coal

"What are the main renewable energy sources?"

"Biofuel

"What is the difference between renewable and non-renewable energy?"

"Renewable can be replenished naturally

"Why are renewable energies becoming more important?"

"Fossil fuels have finite reserves

"Why are some renewable sources unreliable?"

"Depend on weather or time (e.g. solar at night

"What type of current is mains electricity in the UK?"

"AC (alternating current)"

"What is the frequency and potential difference of UK mains supply?"

"50 Hz

"What type of current do batteries supply?"

"DC (direct current)"

"What is the colour and purpose of the live wire?"

"Brown

"What is the colour and purpose of the neutral wire?"

"Blue

"What is the colour and purpose of the earth wire?"

"Green and yellow stripes

"What happens if the live wire touches the metal casing of an appliance?"

"Appliance becomes live and could give a fatal shock"

"How does the earth wire prevent electrocution?"

"Carries current to the ground if a fault occurs"

"What is the National Grid?"

"Network of cables and transformers transferring power from power stations to consumers"

"What do step-up transformers do?"

"Increase potential difference to reduce current and energy loss"

"What do step-down transformers do?"

"Decrease potential difference for safe use by consumers"

"Why were fossil fuels used heavily in the industrial revolution?"

"Easy to mine and provided large amounts of energy"

"Why has renewable energy only recently become more widely used?"

"Technology had to develop to harness renewable sources efficiently"

"What factors affect decisions about energy resources?"

"Environmental