Energy Flashcards
What are the pros and cons of wind turbines and their main use?
- No pollution whilst running
- No fuel costs
- Wind is unreliable as not always high wind speed so may not always meet demand so more would have to be built as not enough
- Spoil the view (visual pollution)
Main use is electricity
RPA 1: how would you carry out to calculate SHC including safety and how to make the test valid
- Measure mass of material used on a balance and wrap block with insulating material
- Use a thermometer to calculate the change in temperature
- Use a joule meter to calculate energy transferred or a volt meter and ammeter ( P=VI then Et=Pxt)
- SHC = △E/m△θ
- For validity repeat experiment to calculate a mean result, control initial temperature
- For safety do not touch immersion heater or block when hot
RPA 1: give two reasons why SHC value may be greater than actual value?
-Some heat energy transferred to the surroundings so temperature increase will not be as high as it should be for total energy transferred.
-Inaccurate reading of temperature (random error)
RPA 2: Suggest how thicker insulation would affect the results.
The temperature decrease would be lower as the rate of temperature decrease would be lower.
How can you explain what material would be the best insulator?
The one that has the lowest thermal conductivity, meaning it has the lowest rate of energy transfer ie bubble wrap
Why is it unlikely for all of electricity in the UK to be able to be generated by solar panels?
Low light intensity in the UK so solar panels are unreliable to meet demand (ie by cloud cover) . As a result, a large area of land would have to be covered to build panels.
Why at the bottom of a slide would riders have approximately the same speed?
1/2mv^2 =mgh
As mass cancels out velocity is only determined by vertical height and gravity, only friction affects speed variations
Give three environmental advantages of using gas power stations over coal power stations.
- No sulfur dioxide so no acid rain
- Less greenhouse gases (CO2) released so less global warming
- Doesn’t cause global dimming
Why may a kettle not immediately begin to heat up?
Takes time for the heating element of the kettle to heat up (as energy must transfer)
Why may different people have different speeds at the end of a zip wire?
Initial speed may not be zero. This adds to the total energy of the system.
What is are advantages and disadvantages of nuclear power and its main use?
- Doesn’t release any pollutants
-> no CO2 so doesn’t cause global warming
-> no sulfur dioxide so no acid rain - Finite
- Radioactive waste which is toxic/harmful so must be stored for many years as damaging to people and environment
Main use is electricity
What does efficient mean and why are people encouraged to use more energy efficient devices?
More input energy transferred usefully for desired output, less energy wasted
Less energy is wasted so minimised environmental impact like lower CO2 emissions so less global warming (as more environmentally aware)
How could you reduce the emission of sulfur dioxide if fossil fuels burnt stay the same?
Remove sulfur before burning fuel.
What does a reliable energy source mean?
Energy is constant so will guarantee to meet demand.
Give three ways of reducing carbon dioxide emissions.
- Use more renewable resources
- carbon capture
- Reduce use of fossil fuel power stations
Explain why a weightlifter’s internal store decreases when he lifts a bar and the bars internal energy store increases by a small amount.
Wasted energy from the weightlifter is transferred as heat to the environment (the bar).
Explain how lubrication/streamlining affects efficiency.
Reduces friction/ air resistance so less (thermal) energy would be wasted to the surroundings. More energy is transferred usefully so efficiency would increase.
Define thermal conductivity.
How quick (rate that ) energy is transferred in a material when it is heated.
Suggest 2 reasons why someones total power output may be higher than calculated.
- Some energy transferred/wasted to the surroundings
- They may have increased their energy
Why is directly supplying electricity more efficient than the National Grid?
Shorter cables so less energy lost (as heat to the surroundings)
Explain the advantages of using energy from nuclear fuels to generate electricity rather than using energy from the wind.
Include in your answer a brief description of the process used to generate electricity from nuclear fuels.
Nuclear uses a small mass of fuel to generate a lot of electricity and so is more reliable. Electricity is made in a nuclear reactor using uranium which splits and releases energy where the energy heats water to steam and turns a turbine linked to a generator.
What does short start up time mean?
Can meet high surges in demand.
Why may have the amount of electricity used for lighting decreased?
People more environmentally aware.
What does it mean to decommission a power station?
Remove radioactive waste
Explain, in terms of particles, how heat is transferred through the glass wall of a boiling tube
Particles vibrate more faster and energy is then transferred by collisions with neighbouring particles (conduction)
What heat transfer do shiny surfaces reduce?
Radiation
How are insulators good at reducing heat transfers?
Trap pockets of air.
Describe what 3 energy transfers materials should reduce to reduce energy loss.
- (Infrared) Radiation
- Conduction
- Convection
Describe how electricity is generated in a hydroelectric power station. Include the useful energy transfers taking place
Water moves (into a DAM) and transfers GPE to KE. This turns a turbine which turns a generator so KE transfers to electrical energy.
What is the effect of kinetic energy if speed and mass is halved?
Mass is halved so kinetic energy decreases by a factor of two and speed is halved so kinetic energy decreases by a factor of four. In total kinetic energy decreases by a factor of 8.
Why may more readings not improve the precision?
May not fit with the previous results, more results means a higher uncertainty and precise results show little uncertainty.
What are two advantages and disadvantages of fossil fuels and their main uses?
- Reliable constant source of energy
- Cheap
- Finite
- Release harmful pollutants ie carbon dioxide (a greenhouse gas) which contributes to global warming
Main uses are transport(oil), electricity(coal) and heating(natural gas)
How is electricity generally produced?
Turbine is turned which turns a generator to produce electricity (KE -> ELECTRICITY)
What is an advantage and disadvantage of geothermal power stations and its main uses?
- Renewable
- Expensive and can only be built in a few areas
Main use is electricity and heating
What is an advantage and disadvantage of biofuels and its main uses?
- Easy to transport and renewable
- Require a large area to grow, so natural habitats are destroyed
Main uses are heating and transport
Why in reality are biofuels not carbon neutral?
Trees may be cut down so can grow, so no longer absorb CO2
Trees may be cut down, and will release CO2 if burned
Energy will be required to harvest biofuels releasing more CO2
What is an advantage and disadvantage of hydroelectric/wave/tidal power and its main use?
- Renewable no harmful polluting gases produced
- Can cause flooding, which damages habitats
Main use is electricity
Give three ways to reduce heat loss by conduction/convection in the home
- Low thermal conductivity and thick walls(conduction only)
- Double glazing with pockets of air as air is a poor conductor
- Cavity walls reducing convection
What is an advantage and disadvantage of solar power and what is its main use?
- Renewable: no pollutants released
- Unreliable as not always sunny so many would have to be built to meet demand
Main use is heating - absorb light energy (from sunlight) to convert to heat to warm water
How do energy resources heat?
Use energy to heat up buildings by heating up water
How are fossil fuels used to produce electricity?
Fossil fuel is burnt releasing energy that boils water and turn it into steam.
The steam rises past turbines and causes them to spin.
The turbines are connected to generators which are spun to generate electricity.
Transformers are used to step up the voltage before feeding the electricity into the National Grid.
Transformers are used to step down the voltage before feeding electricity into homes.
Explain energy changes for a moving object hitting an obstacle
Kinetic energy is transferred to thermal energy store. Some kinetic energy remains as the object moves backwards after the collision
Explain energy changes for an object accelerated by a constant force
Work is done by a force on an object which is converted to the object’s kinetic store
Explain energy changes for a vehicle slowing down
Kinetic energy decreases as is transferred to thermal energy to the surroundings due to friction
Explain energy changes for bringing water to a boil in an electric kettle
Chemical energy is transferred to electrical energy which is transferred to thermal energy which heats up water
Why can environmental issues identified by scientists not always be dealt with?
Political, ethical, social, economic reasons
How can energy be transferred? (4)
Mechanically, electrically, by radiation, by heating
Give three way to reduce effects of burning fossil fuels without burning less
- plant more trees whilst trying to use more renewable resources
- carbon capture
- remove impurities in fossil fuels like sulfur before burning
Describe how ‘carbon capture’ would prevent the build-up of carbon dioxide in the atmosphere
carbon dioxide is not released (into the atmosphere) but is (caught and) stored (in huge natural containers)
Define a system
An object or a group of objects
