Stores and Transfers
What energy store does a moving object have?
Kinetic.
What does energy efficiency mean?
How much energy is useful.
What unit is power measured in?
Watts (W)
Name one renewable energy resource.
Wind / solar / hydroelectric / biomass / wave / tidal / geothermal
Which type of heat transfer needs particles touching? Conduction, Convection or Radiation?
Conduction.
What energy store is in a stretched spring?
Elastic.
Is a device with high energy efficiency better or worse?
Better.
What unit is time measured in for energy calculations?
Seconds.
Name one non-renewable energy resource.
Coal / oil / gas / nuclear.
Which type of heat transfer happens in liquids and gases? Conduction, Convection or Radiation?
Convection.
Name one way energy can be transferred.
Heating / light / sound / electrical.
What usually happens to wasted energy?
Lost as heat.
Write the equation for energy transferred.
Energy = power × time
Why are fossil fuels non-renewable?
They will run out one day.
They are being used faster than they can be replaced.
Which type of heat transfer does not need particles? Conduction, Convection or Radiation?
Radiation.
When a lamp is on, what useful energy transfer occurs?
Electrical → light
A heater is 80% efficient. Is more energy useful or wasted?
Useful.
A 100 W TV is on for 2 hours. How much energy does it use in Joules?
2 hours x 60 = 120 mins
120 x 60 = 7200 seconds
100 X 7200 = 720,000 J
Which resource uses sunlight directly to generate electricity?
Solar.
What can we do/add to an object to prevent heat escaping?
Insulation.
A moving car slows down due to friction. Which energy store increases and where?
Thermal store of surroundings.
A device transfers 80 J of useful energy out of 100 J total. What is its efficiency?
80%
Electricity costs £0.20 per kWh. How much does it cost to run a 2 kW heater for 3 hours?
2 x 3 = 6 kWh
6 x 0.20 = 120p = £1.20
Give one advantage of renewable energy over fossil fuels.
Less pollution/greenhouse gases/climate change.
Won't run out.
Why does hot air rise in convection currents?