P1 - Energy Flashcards
What is energy in the context of energy stores and systems?
Energy is never used up; it is transferred between different energy stores and objects.
What happens when energy is transferred to an object?
The energy is stored in one of the object’s energy stores.
List the different types of energy stores.
- Thermal energy stores
- Kinetic energy stores
- Chemical energy stores
- Magnetic energy stores
- Gravitational potential energy stores
- Electrostatic energy stores
- Elastic potential energy stores
- Nuclear energy stores
What is another term for thermal energy stores?
Internal energy stores.
What is a system?
A system is a single object or a group of objects that you’re interested in.
What occurs when a system changes?
Energy is transferred into or away from the system, between different objects in the system, or between different types of energy stores.
What defines a closed system?
A closed system is one where neither matter nor energy can enter or leave.
What is the net change in total energy of a closed system?
The net change in the total energy of a closed system is always zero.
How can energy be transferred by heating?
Energy is transferred to an object, such as water in a kettle, by heating, causing an increase in its thermal energy store.
What is work done in terms of energy transfer?
Work done is another way of saying energy transferred; they are the same thing.
How can work be done in a circuit?
Work is done against resistance when current flows.
What happens when a ball is thrown upwards?
The initial force causes an energy transfer from the chemical energy store of the person’s arm to the ball’s kinetic energy store.
What does gravitational force do to a ball dropped from height?
The gravitational force does work, transferring energy from the ball’s gravitational potential energy store to its kinetic energy store.
What occurs when brakes are applied to a car?
The friction between the brakes and wheels does work, transferring energy from the wheels’ kinetic energy stores to the thermal energy store of the surroundings.
Fill in the blank: In a collision between a car and a stationary object, the normal contact force does work, causing energy to be transferred from the car’s kinetic energy store to _______.
[elastic potential and thermal energy stores of the object]
True or False: Energy can also be transferred away by sound waves.
True
What does movement mean in terms of energy?
Movement means energy in an object’s kinetic energy store.
What factors determine the energy in an object’s kinetic energy store?
The energy in the kinetic energy store depends on the object’s mass and speed.
What happens to the kinetic energy store when mass or speed increases?
The more mass and the faster the object is going, the more energy there will be in its kinetic energy store.
What is the formula for calculating kinetic energy?
Kinetic energy (E_k) = ½mv².
Calculate the kinetic energy of a car with a mass of 2500 kg traveling at 20 m/s.
Kinetic energy = 500,000 J.
What energy store do raised objects have?
Raised objects store energy in gravitational potential energy stores.
What is required to lift an object in a gravitational field?
Lifting an object requires work, causing a transfer of energy to the gravitational potential energy store.
How does height affect gravitational potential energy?
The higher the object is lifted, the more energy is transferred to its gravitational potential energy store.
What factors determine the energy in a gravitational potential energy store?
The amount of energy depends on the object’s mass, height, and the strength of the gravitational field.
What is the formula for gravitational potential energy?
Gravitational potential energy (E_g.p.e) = mgh.
What happens to energy when an object falls without air resistance?
Energy lost from the gravitational potential energy store equals energy gained in the kinetic energy store.
What effect does air resistance have on falling objects?
Air resistance acts against falling objects, causing some energy to be transferred to other energy stores, such as thermal energy.
What is elastic potential energy?
Elastic potential energy is energy stored when an object is stretched or squashed.
What is the condition for energy to be stored in an elastic potential energy store?
The limit of proportionality must not be exceeded.
What is the formula for calculating elastic potential energy?
Elastic potential energy (E_e.p.e) = ½ke².
What is specific heat capacity?
The amount of energy needed to raise the temperature of 1 kg of a substance by 1 °C.
How much energy is required to warm 1 kg of water by 1 °C?
42000 J.
How much energy is required to warm 1 kg of mercury by 1 °C?
139 J.
What does a high specific heat capacity indicate about a material?
It needs to gain a lot of energy to increase its temperature and can store a lot of energy when cooling down.
What is the equation that links energy transferred to specific heat capacity?
ΔE = mcΔθ.
In the equation ΔE = mcΔθ, what does each symbol represent?
- ΔE: Change in energy transferred
- m: Mass (kg)
- c: Specific heat capacity (J/kg°C)
- Δθ: Change in temperature (°C)
What is the first step in investigating the specific heat capacity of a solid material?
Measure the mass of the block.
What should you wrap the block of material in during the specific heat capacity experiment?
An insulating layer (e.g., a thick layer of newspaper).
What is the purpose of the heater in the specific heat capacity experiment?
To transfer energy electrically from the power supply to the material’s thermal energy store.
What should you measure every minute during the experiment?
The temperature and current, I.
What is the formula to calculate the power supplied to the heater?
P = VI.
What formula is used to calculate the energy transferred to the heater over time?
E = Pt.
What can you plot to analyze the specific heat capacity experiment?
A graph of energy transferred to the thermal energy store of the block against temperature.
How do you find the specific heat capacity from the gradient of the graph?
Specific heat capacity = 1 ÷ (gradient x mass of the block).
True or False: The current through the circuit changes as the block heats up.
False.
What can you investigate besides solids in the specific heat capacity experiment?
The specific heat capacity of liquids.
Fill in the blank: Specific heat capacity is a measure of how _____ it is to change the temperature of a substance.
hard
What is specific heat capacity?
The amount of energy needed to raise the temperature of 1 kg of a substance by 1 °C.
How much energy is required to warm 1 kg of water by 1 °C?
42000 J.
How much energy is required to warm 1 kg of mercury by 1 °C?
139 J.
What does a high specific heat capacity indicate about a material?
It needs to gain a lot of energy to increase its temperature and can store a lot of energy when cooling down.
What is the equation that links energy transferred to specific heat capacity?
ΔE = mcΔθ.
In the equation ΔE = mcΔθ, what does each symbol represent?
- ΔE: Change in energy transferred
- m: Mass (kg)
- c: Specific heat capacity (J/kg°C)
- Δθ: Change in temperature (°C)
What is the first step in investigating the specific heat capacity of a solid material?
Measure the mass of the block.
What should you wrap the block of material in during the specific heat capacity experiment?
An insulating layer (e.g., a thick layer of newspaper).
What is the purpose of the heater in the specific heat capacity experiment?
To transfer energy electrically from the power supply to the material’s thermal energy store.
What should you measure every minute during the experiment?
The temperature and current, I.
What is the formula to calculate the power supplied to the heater?
P = VI.
What formula is used to calculate the energy transferred to the heater over time?
E = Pt.
What can you plot to analyze the specific heat capacity experiment?
A graph of energy transferred to the thermal energy store of the block against temperature.
How do you find the specific heat capacity from the gradient of the graph?
Specific heat capacity = 1 ÷ (gradient x mass of the block).
True or False: The current through the circuit changes as the block heats up.
False.
What can you investigate besides solids in the specific heat capacity experiment?
The specific heat capacity of liquids.
Fill in the blank: Specific heat capacity is a measure of how _____ it is to change the temperature of a substance.
hard
What is the conservation of energy principle?
Energy is always conserved; it can be transferred, stored, or dissipated, but never created or destroyed.
What is dissipated energy sometimes referred to as?
‘Wasted energy’ because it is stored in a way that is not useful.
In a mobile phone, where does energy transfer occur from?
From the chemical energy store of the battery.
What happens to energy when a cold spoon is dropped into hot soup in a closed system?
Energy is transferred from the thermal energy store of the soup to the thermal energy store of the spoon.
What is the net change in energy for a closed system?
Zero, as energy transfers occur within the system but no energy leaves.
What is power defined as?
The rate of energy transfer or the rate of doing work.
How is power measured?
In watts; 1 watt = 1 joule of energy transferred per second.
What is the formula to calculate power using energy transferred?
P = E / t
What is the formula to calculate power using work done?
P = W / t
What characterizes a powerful machine?
It transfers a lot of energy in a short period of time.
If two identical cars race, how does the power of their engines affect the outcome?
The car with the more powerful engine will reach the finish line faster.
How do you calculate the power of a motor given work done and time taken?
P = W / t
If Motor A lifts a stunt performer in 50 seconds and does 8000 J of work, what is its power?
160 W
Fill in the blank: Energy can be ______, stored, or dissipated.
transferred
True or False: Energy can be created in a closed system.
False
What effect does energy transfer have on the temperature of the soup when a cold spoon is added?
The soup cools down slightly.
What effect does frictional force have on energy in a moving system?
It causes energy in the system to be dissipated.
For example, air resistance can transfer kinetic energy to thermal energy.
What is the purpose of lubricants in moving systems?
To reduce the friction between the surfaces of objects that are rubbed together.
Lubricants are usually liquids like oil that can easily flow and coat surfaces.
How does streamlining affect air resistance?
Streamlining reduces air resistance.
This is important for improving the efficiency of moving objects.
What happens when an object is heated in terms of particle energy?
Energy is transferred to the kinetic energy stores of its particles, causing them to vibrate more and collide.
This process is known as conduction.
What is thermal conductivity?
A measure of how quickly energy is transferred through a material.
Materials with high thermal conductivity transfer energy faster.
What occurs to particle density when particles in a heated substance move faster?
The density of the region being heated decreases.
This is because the space between individual particles increases.
What is convection?
The movement of energetic particles from hotter to cooler regions in liquids and gases.
This occurs because warmer, less dense regions rise above denser, cooler regions.
What are two methods to reduce energy losses through heating in a house?
1) Use thick walls made from low thermal conductivity materials.
2) Use thermal insulation.
These methods slow the rate of energy transfer.
What is cavity wall insulation?
Filling the air gap in cavity walls with foam to reduce energy transfer by conduction and convection.
Cavity walls consist of an inner and outer wall with an air gap.
How does loft insulation work?
It reduces convection currents in lofts.
Convection currents involve air particles being heated, rising, cooling, and then sinking.
What is the function of double-glazed windows?
To prevent energy transfer by conduction through windows.
They have an air gap between two sheets of glass.
How do draught excluders help with energy transfer?
They reduce energy transfers by convection around doors and windows.
This helps maintain indoor temperatures.
Fill in the blank: Reducing the difference between the _______ inside and outside a house will reduce the rate of energy transfer.
temperature
What is the primary reason useful devices are considered useful?
They can transfer energy from one store to another.
What happens to some of the input energy in most energy transfers?
It is usually wasted by being transferred to a useless energy store, typically a thermal energy store.
How is the efficiency of a device determined?
The less energy that is wasted in the energy store, the more efficient the device is.
What are three methods to improve the efficiency of energy transfers?
- Insulating objects
- Lubricating them
- Making them more streamlined
What is the formula for calculating efficiency in energy transfers?
Efficiency = Useful output energy transfer / Total input energy transfer
How can you express efficiency as a percentage?
Multiply the decimal efficiency by 100.
If a blender is 70% efficient and has a total input power of 600 W, what is the useful output power?
420 W
What is the first step to calculate useful power output from efficiency?
Change the efficiency from a percentage to a decimal.
What is a key characteristic of electric heaters regarding efficiency?
They are usually 100% efficient.
What typically happens to energy in devices after use?
It ultimately ends up in thermal energy stores.
Fill in the blank: NO device is ______ efficient.
100%
True or False: All energy transfers can be 100% efficient.
False
What are the three main fossil fuels?
1) Coal
2) Oil
3) (Natural) Gas
These fossil fuels will eventually run out and contribute to environmental damage.
What are renewable energy resources?
1) The Sun (Solar)
2) Wind
3) Water waves
4) Hydro-electricity
5) Bio-fuel
6) Tides
7) Geothermal
Renewable energy resources can be replenished as they are used and generally cause less environmental harm.
True or False: Renewable energy resources will never run out.
True
Unlike non-renewable resources, renewable resources can regenerate.
What is a common use of energy resources in transportation?
Fuel for vehicles
Both renewable and non-renewable resources are utilized for various transportation methods.
What type of vehicles use petrol and diesel?
Most cars
Petrol and diesel are derived from oil, a non-renewable resource.
Fill in the blank: ______ is used in some old-fashioned steam trains to boil water.
Coal
Coal is a non-renewable energy source.
What types of energy can power vehicles?
1) Petrol and diesel
2) Electricity
3) Bio-fuels
Electricity can be generated from both renewable and non-renewable sources.
What is the most widely used fuel for heating homes in the UK?
Natural gas
Natural gas is a non-renewable energy resource.
What device uses geothermal energy to heat buildings?
Geothermal heat pump
This system pumps heated water into radiators throughout the home.
Fill in the blank: Solar water heaters use the sun to heat ______.
Water
The heated water is then pumped into radiators.
What type of heaters use electricity generated from non-renewable resources?
Electric heaters
These are sometimes referred to as storage heaters.
What is a characteristic of renewable energy resources?
They can be renewed as they are used.
However, they may be less reliable due to dependence on weather conditions.
True or False: Burning bio-fuel is a renewable method of heating.
True
Only the bio-fuel part is renewable; if mixed with petrol or diesel, only the bio-fuel contributes to renewable energy.
What are the three main fossil fuels?
1) Coal
2) Oil
3) (Natural) Gas
These fossil fuels will eventually run out and contribute to environmental damage.
What are renewable energy resources?
1) The Sun (Solar)
2) Wind
3) Water waves
4) Hydro-electricity
5) Bio-fuel
6) Tides
7) Geothermal
Renewable energy resources can be replenished as they are used and generally cause less environmental harm.
True or False: Renewable energy resources will never run out.
True
Unlike non-renewable resources, renewable resources can regenerate.
What is a common use of energy resources in transportation?
Fuel for vehicles
Both renewable and non-renewable resources are utilized for various transportation methods.
What type of vehicles use petrol and diesel?
Most cars
Petrol and diesel are derived from oil, a non-renewable resource.
Fill in the blank: ______ is used in some old-fashioned steam trains to boil water.
Coal
Coal is a non-renewable energy source.
What types of energy can power vehicles?
1) Petrol and diesel
2) Electricity
3) Bio-fuels
Electricity can be generated from both renewable and non-renewable sources.
What is the most widely used fuel for heating homes in the UK?
Natural gas
Natural gas is a non-renewable energy resource.
What device uses geothermal energy to heat buildings?
Geothermal heat pump
This system pumps heated water into radiators throughout the home.
Fill in the blank: Solar water heaters use the sun to heat ______.
Water
The heated water is then pumped into radiators.
What type of heaters use electricity generated from non-renewable resources?
Electric heaters
These are sometimes referred to as storage heaters.
What is a characteristic of renewable energy resources?
They can be renewed as they are used.
However, they may be less reliable due to dependence on weather conditions.
True or False: Burning bio-fuel is a renewable method of heating.
True
Only the bio-fuel part is renewable; if mixed with petrol or diesel, only the bio-fuel contributes to renewable energy.
What is the primary function of wind turbines?
To produce electricity through a generator powered by rotating blades
Wind turbines are placed in exposed locations to harness wind energy.
What are the environmental impacts of wind turbines?
Minimal pollution, but they spoil the view and can be noisy
Noise can be an issue for people living nearby.
How many wind turbines are needed to replace one coal-fired power station?
About 1500 wind turbines
This large number covers significant ground, affecting scenery.
What is a key limitation of wind power generation?
Turbines stop when there’s no wind or if the wind is too strong
This leads to challenges in meeting extra demand.
What percentage of time do wind turbines typically produce electricity?
70-85% of the time
This indicates their reliability but also their limitations.
What are the financial aspects of wind power?
High initial costs but no fuel costs and minimal running costs
The absence of fuel costs contributes to long-term savings.
What happens to the landscape if wind turbines are removed?
The noise and view return to normal
There is no permanent damage to the landscape.
What is the main function of solar cells?
To generate electric currents directly from sunlight
They are often used for small-scale applications like charging batteries.
Where is solar power commonly utilized?
In remote places, electric road signs, and satellites
It’s particularly useful where other energy sources are limited.
What is a drawback of solar power generation?
Cannot increase power output during extra demand
This is similar to wind power limitations.
What are the initial and running costs associated with solar cells?
High initial costs, but energy is free afterward and running costs are minimal
This makes solar energy cost-effective in the long run.
What is geothermal power derived from?
Energy in underground thermal energy stores
It is sourced from the decay of radioactive elements deep within the Earth.
What are the advantages of geothermal power?
Reliable and does very little environmental damage
It can be used for electricity generation or direct heating.
What are the main drawbacks of geothermal power?
Limited suitable locations for power plants and high building costs
These factors can affect the feasibility of geothermal energy projects.
What is hydro-electric power?
Hydro-electric power is generated by flooding a valley and allowing water to flow through turbines.
What is a major environmental impact of hydro-electric power?
Flooding of the valley can lead to rotting vegetation, releasing methane and CO₂, and loss of habitat for species.
What is a significant advantage of hydro-electric power?
It can provide an immediate response to increased demand for electricity.
When does reliability of hydro-electric power become an issue?
Reliability is affected during times of drought.
What are the initial costs associated with hydro-electric power?
Initial costs are high, but there are no fuel costs and minimal running costs.
How can hydro-electric power be beneficial in remote areas?
It can generate electricity on a small scale.
How is wave power generated?
By using lots of small wave-powered turbines located around the coast.
What are the main problems associated with wave power?
Disturbing the seabed, spoiling the view, and being a hazard to boats.
Why is wave power considered unreliable?
Waves tend to die out when the wind drops.
What is a limitation of wave power for large-scale energy production?
It is unlikely to provide energy on a large scale but can be useful on small islands.
What is a tidal barrage?
A tidal barrage is a big dam built across river estuaries with turbines.
How do tides generate electricity?
Tides fill up the estuary and water is released through turbines at a controlled speed.
What natural forces produce tides?
The gravitational pull of the Sun and Moon.
What are the main environmental concerns with tidal barrages?
Preventing free access by boats, spoiling the view, and altering wildlife habitats.
How reliable are tides for energy generation?
Tides happen twice a day without fail and are predictable.
What is a drawback of tidal power related to tide heights?
Lower (neap) tides provide significantly less energy than bigger (spring) tides.
What are the initial costs associated with tidal power?
Initial costs are moderately high, but there are no fuel costs and minimal running costs.
What is the potential of tidal power?
It has the potential for generating a significant amount of energy in suitable estuaries.
What are bio-fuels made from?
Bio-fuels are made from either plant products or animal dung
Bio-fuels can be solid, liquid, or gas.
True or False: Bio-fuels are always carbon neutral.
False
Bio-fuels are considered carbon neutral only if plants are grown at the same rate they are burned.
What is a reliability feature of bio-fuels?
Crops can be grown all year round
Bio-fuels are continuously produced and stored for energy needs.
What is a concern regarding the cultivation of bio-fuels?
Growing crops for bio-fuels may limit space and water for food crops
The cost to refine bio-fuels is also very high.
What environmental issue can arise from clearing forests for bio-fuel production?
Loss of natural habitats for species
The decay and burning of vegetation increases CO2 and methane emissions.
How do fossil fuels and nuclear energy respond to demand?
They can respond quickly to changes in demand
There is enough fossil and nuclear fuel to meet current demand.
What is a drawback of fossil fuels?
They are slowly running out
Some fossil fuel stocks may run out within a hundred years.
What are the running costs of fossil fuel power plants compared to setup costs?
Running costs are not that expensive
Setup costs can be quite high.
What gas is released into the atmosphere when coal, oil, and gas are burned?
CO2
This contributes to the greenhouse effect and global warming.
What does burning coal and oil release that causes acid rain?
Sulfur dioxide
Acid rain can harm trees, soils, and ecosystems.
How can acid rain be reduced?
By taking sulfur out before burning fuel or cleaning emissions
This is a method to mitigate environmental impact.
What is a significant environmental impact of coal mining?
It spoils the landscape, especially with open-cast mining
Fossil fuel power plants can also spoil views.
What are the consequences of oil spillages?
They affect mammals and birds living in and around the sea
Oil spillages are serious environmental problems.
What is a major drawback of nuclear power?
Nuclear waste is very dangerous and difficult to dispose of
Nuclear power has high overall costs due to power plant and decommissioning expenses.
What risk is associated with nuclear power?
Risk of major catastrophes like the Fukushima disaster
Radiation can be very dangerous to humans.
What has caused changes in the types of energy resources we use over time?
Breakthroughs in technology, understanding environmental impacts, changes in cost
These factors contribute to the evolution of energy resource use.
What has been the trend in electricity use in the UK since the 21st century?
Electricity use has been slowly decreasing
This decrease is due to increased efficiency in appliances and careful energy use.
What are the primary sources of electricity in the UK?
Fossil fuels and nuclear power
This includes oil for cars and gas for heating and cooking.
Why do people want to use more renewable energy resources?
Environmental damage from fossil fuels, awareness of non-renewables running out
There is a growing desire to reduce reliance on non-renewable resources.
What pressure has led governments to introduce targets for renewable resource use?
Pressure from other countries and the public
This pressure affects energy providers to adopt renewable energy.
What types of vehicles are gaining popularity due to the shift towards renewable energy?
Electric cars and hybrids
Hybrids use two fuels, such as petrol and electricity.
What are the main limitations on the use of renewable energy resources?
Reliability, cost, and political issues
These factors hinder the transition to renewable energy.
What is a significant financial challenge for energy providers in building renewable power plants?
The high cost of building new renewable power plants
Providers are often reluctant due to the cost-effectiveness of fossil fuels.
What ethical concerns arise from the placement of new renewable power plants like wind farms?
Protests from people who do not want to live near them
There are debates about the ethics of imposing such facilities on communities.
Why is wind power considered less reliable than traditional fossil fuels?
Wind power cannot increase its output on demand
This lack of reliability necessitates a mix of power sources.
What is a financial barrier for individuals regarding renewable energy options like hybrid cars and solar panels?
These options are generally expensive
Although costs are decreasing, they remain unaffordable for many.
Fill in the blank: The _______ of switching to renewable power must be covered by customers or through government taxes.
cost
There are ethical discussions surrounding the financial burden on customers.
True or False: Research on improving the reliability and cost of renewables can be completed quickly.
False
Improvements may take years, necessitating continued use of non-renewable power.
