Topic 1-Energy Flashcards
What is specific heat capacity?
Amount of energy needed to raise the temp of 1kg of a substance by 1 degree Celsius
What is power?
The rate at which work is done/ energy is transferred
Describe the energy changes when ball is thrown upwards?
Kinetic energy is converted to GPE
When at peak, its maximum GPE
GPE is converted back to kinetic energy
State 4 different energy stores
Chemical store
Kinetic store
GPE store
EPE store
State the law of energy conservation
Energy cannot be created or destroyed , only transferred to different forms
What is waste energy?
Energy not used by device for desired purpose
How can the efficiency of a system be increased
Reducing waste output (lubrication/ thermal insulation)
State 3 methods of reducing heat loss in a building
- Double glazing
- Loft and wall insulation
- Thicker walls
How can lubricating reduce energy transfer?
Reduces friction and therefore energy loss due to heating
What is a renewable energy source?
An energy source which can be replenished as it is being used up
Give 4 examples of renewable energy sources
Wind
Solar
Tidal
Geothermal
Give and example of a non renewable energy resource
Fossil fuels (coal, oil, gas)
State 2 disadvantages of using renewable energy resources
Output determined by external factors (wind) so unreliable
Very costly
What are the environmental impacts of burning fossil fuel?
CO2 contributes to greenhouse effect and therefore global warming
State 3 advantages of fossil fuel as a resource
Reliable- can generate power any time
Can produce large amounts of energy
Cost effective
What are 3 advantages of nuclear power?
Large amounts of energy for small amount of fuel
Doesn’t release greenhouse gases and contribute to climate change
Cost efficient
What are 2 disadvantages of nuclear power?
Nuclear waste is harmful to humans
Risk of nuclear accidents
Non renewable
How does hydroelectric power produce energy?
Rainwater collects behind dam
water is released and turns turbine
Turbine turns generator and produces electricity
Describe energy transfers for a bungee jumper
Falling- GPE converted to KE
Cord tightens- KE converted and stores as EPE
Lowest point- initial GPE equals EPE stored in cord
Why does a bungee jumper slow down when the cord begins to stretch?
KE decreases as it is converted to EPE
Since KE is proportional to velocity, when KE decreases, so does velocity
Give examples of chemical energy stores
- Food
- Fuel
- Batteries
Describe energy changes that occur in a filament lamp
Electrical energy transferred to light and heat energy
Light- useful, heat- waste
What can be said about the energy transfer of a material with high thermal conductivity?
Rate of energy transfer through material is higher for a material with higher thermal conductivity
Do double glazed windows have a higher or lower thermal conductivity than single-glazed windows?
Lower- meaning less energy transfers through them
What 2 factors affect the rate of cooling of a building?
- Thickness of the walls
2. Thermal conductivity of the walls
How can the efficiency of a mechanical machine with moving parts be improved?
Lubrication of moving parts- reduce friction and therefore energy loss due to heating
How can efficiency of radiator be improved?
Install metal foil sheets behind radiator- reflect heat back into room rather than it being absorbed into walls
What are the advantages of generating power using gas rather than coal?
- Gas power stations have short start up times
2. Lower emissions of CO2
What are 2 disadvantages of using biofuels?
- In order to grow biofuels you need to destroy land
2. When plants are burned they release CO2
What are the advantages of tidal energy sources?
- Dont produce greenhouse gases
2. Reliable, as tides happen twice a day
What are disadvantages of hydroelectric power?
- Dam may cause flooding
2. Can cost a lot to install required infrastructure
What are the advantages of solar panels?
- Don’t cause environmental harm
2. Can be used in remote areas
Give examples of social factors which may act as deterrents for some energy production
- Visual pollution
2. Sound pollution
