P1 - Energy Flashcards
Name 8 stores of energy
Magnetic
Internal (thermal)
Chemical
Kinetic
Electrostatic
Elastic potential
Gravitational potential
Nuclear
Define magnetic energy
The energy stored when repelling poles have been pushed closer together or when attracting poles have been pulled further apart.
Define kinetic energy
The energy of a moving object.
Define internal (thermal) energy
The total kinetic and potential energy of the particles in an object, in most cases this is the vibrations - also known as the kinetic energy - of particles.
Define chemical energy
The energy stored in chemical bonds, such as those between molecules.
Define gravitational potential energy
The energy of an object at height.
What are the four types of energy transfers?
Mechanical work
Electrical work
Heating
Radiation
What is mechanical work?
A force moving an object through a distance.
What is electrical work?
The charges moving due to a potential difference.
What is heat?
Heat is the flow of kinetic energy from one object to another.
What is radiation?
Energy transferred as a wave.
What is the equation for kinetic energy?
1/2 x mass x velocity^2
What is the equation for elastic potential energy?
1/2 x spring constant x extension^2
What is the equation for gravitational potential energy?
Mass x GFS x height
What is the Specific Heat Capacity of a substance?
The amount of energy needed to raise the temperature of 1kg of a substance by 1 degree.
Define power.
The rate at which energy is transferred (work is done).
What is the equation for power?
Power = work done (energy transferred) / time
Describe the energy transferences for a bungee jumper.
When falling GPE is converted into KE of the jumper. As the cord tightens KE is transferred and stored as EPE. At the jumpers lowest point the amount of GPE at the jumpers highest point is the same as the EPE stored in the cord.
Explain why a bungee jumper slows down when the cord begins to stretch.
KE is converted into EPE and since KE is proportional to velocity squared as KE decreases so does velocity.
Give examples of chemical energy stores.
Food, fuel, batteries.
What is waste energy?
The energy that is not used by it’s device for it’s desired purpose.
Describe the energy changes that occur in a filament light-bulb.
Electrical energy is transferred into light and heat energy.
Light is a useful energy form, heat is a waste energy form.
Equation for efficiency.
Useful power output / total power output
How can efficiency of a system be increased?
Waste energy reduced.
Recycling waste output.
What is thermal conductivity?
The rate of heat energy transfer by conduction across a material.
What key factors affect the rate of cooling of a building?
Thickness of the walls.
Thermal conductivity of walls.
Do double-glazed windows have a lower or higher thermal conductivity than single-glazed windows?
Lower, meaning less energy transfers through them.
State the consequence for an energy transfer of a material that has a high thermal conductivity?
The rate of energy transfer through the material is high. Heat energy is lost through it.
How can the efficiency of a radiator be increased?
Installing foil metal sheets behind the radiator to reflect the heat back into the room rather than it being absorbed by the walls.
What is a renewable energy resource?
An energy source that can be replenished as it is being used up.
Give 4 examples of a renewable energy resource.
Solar energy
Wind energy
Hydro-electricity
Tidal energy
Give three disadvantages of using renewable energy.
Unreliable
Less efficient than non-renewable sources
Expensive
What are the two environmental impacts of burning fossil fuels?
Carbon dioxide enhances the greenhouse effect.
Sulphur dioxide causes acid rain.
Give 3 advantages of fossil fuels.
Reliable
Can produce large amounts of energy
Relatively abundant- so cost effective
Give 3 advantages of nuclear power.
Doesn’t release greenhouse gases.
Large amounts of energy for small amounts of fuel.
Low fuel costs.
Give 3 disadvantages of nuclear power.
- Non-renewable energy resource
- Releases nuclear waste, harmful to humans
- Risk of nuclear accidents- fatal and has consequences on the environment
How does hydro-electric power produce energy?
Rainwater collects behind a dam. When the water is released it turns a turbine. The turbine turns a generator, which produces electricity.
Give 3 disadvantages of biofuels
Releases greenhouse gases
Need to destroy land (burning crops or destroying habitats)
Land could be used to farm food
What are the three advantages of tidal energy?
No greenhouse gases produced.
Cheap to run as tides are natural.
Reliable as tides happen twice a day.
What are the disadvantages of hydro-electric power.
May cause flooding.
Can cost a lot to install the required infrastructure.
Two social factors which may act as a deterrent for wind farms.
Visual pollution
Noise pollution
What are the three advantages of solar panels.
Can be used easily in remote areas where other types of energy are less accessible.
Causes no harm to the environment.
Renewable.
What’s the conservation of energy law?
Energy cannot be created or destroyed only transferred usefully, stored or dissipated.
What’s the unit for SHC?
J/kg degrees Celsius
What does 1 Watt represent?
An energy transfer of 1 joule per second.
What are the energy store changes when an object is accelerated by a constant force?
Work is done on the object. The work is transferred to the store of kinetic energy causing it to move.
What is work done?
The amount of energy transferred.
Equation for work done.
Work done = force x distance
What is the equation for thermal energy?
Mass x SHC x change in temperature
What are the advantages of natural gas compared to coal?
Releases less greenhouse gas emissions.
Burns more efficiently making it better costs wise.
What is the difference between heat and temperature?
Temperature is the average kinetic energy of a substance.
Heat is the flow of kinetic energy.
