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GCSE Physics > P1 - Energy > Flashcards

P1 - Energy Flashcards

1
Q

What are the 8 types of energy sortes?

A
  • Thermal
  • Kinetic
  • Gravitational
  • Elastic potential
  • Chemical
  • Magnetic
  • Nuclear
  • Electrostatic
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2
Q

What are the types of energy transfer?

A
  • Mechanically (by a force doing work)
  • Electrically (work done by moving charges)
  • By heating
  • By radiation (through the EM spectrum, e.g. light or UV radiation) Overall, energy can be transferred by heating or by doing work
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3
Q

What is a closed system?

A

Closed systems are ones where neither energy nor matter can leave. The net change in total energy is always zero

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4
Q

What is the equation for kinetic energy?

A

Kinetic energy (J) = ½ x mass (kg) x velocity2 (m/s)

Ek = ½ mv2

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5
Q

Kinetic energy (J) = ½ x mass (kg) x velocity2 (m/s) Ek = ½ mv2

A

Gravitational potential energy (J) = mass (kg) x gravitational field strength (N/kg) x height (m)

Ep = mgh

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6
Q

What is the law of conservation of energy?

A

Energy can be transferred usefully, stored or dissipated, but can never be created or destroyed.

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7
Q

Dissipated energy is often referred to as ___ energy

This is usually transferred to a useless ___ store

A

Wasted, thermal energy

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8
Q

What is power and what is it measured in?

A

Power is the rate of energy transfer / work done

Measured in watts (W)

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9
Q

What are the 2 equations for power?

A

1) Power (W) = energy transferred (J) ÷ time (s)

P = E/t

2) Power = work done (J) ÷ time (s)

P = W/t

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10
Q

No device is 100% efficient, except for ____

A

Electric heaters

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11
Q

What are the 2 ways to calculate efficiency?

A

1) Efficiency = useful energy output ÷ total energy input

2) Efficiency = useful power output ÷ total power input

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12
Q

What causes energy to be wasted?

A

When something moves, there’s usually at least one frictional force acting against it, causing some energy in the system to be dissipated

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13
Q

What are three ways to reduce unwanted energy transfers?

A
  • Lubrication
  • Streamlining
  • Thermal insulation
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14
Q

How can lubrication reduce unwanted energy transfers?

A

Lubrication reduces frictional forces between surfaces of objects that are being rubbed together

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15
Q

Why are lubricants usually liquids (e.g. oil)?

A

So that they coat objects and flow easily

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16
Q

How can streamlining reduce unwanted energy transfers?

A

Streamlining reduces air resistance. Air resistance transfers energy from an object’s kinetic to thermal energy store

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17
Q

In what two ways can heating occur?

A
  • Conduction

- Convection

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18
Q

How does heating occur by conduction?

A
  • When an object is heated, energy is transferred to the kinetic energy stores of its particles
  • This causes them to vibrate more and therefore collide more with each other
  • During these collisions, energy is transferred between the particles’ kinetic energy stores: this is conduction
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19
Q

How does heating occur by convection?

A
  • If particles are free to move (so in a gas/liquid), an increase in temperature means that energy is transferred to the kinetic energy stores of its particles
  • Particles move faster, so spacing between particles therefore increases
  • This causes the density of a heated region to decrease
  • The warmer, less dense region will rise above cooler, denser regions
  • So more energetic particles move from hotter to cooler regions: this is convection
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20
Q

What are three examples of thermal insulation? (conduction)

A
  • Having thick walls made from a material with low thermal conductivity
  • Cavity walls: an inner and outer wall with an air gap in the middle. The gap reduces the amount of energy transferred by conduction through the walls
  • Double glazing works in the same way: the air gap between two sheets of glass prevents energy transfer by conduction through the windows
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21
Q

What are three examples of thermal insulation? (convection)

A
  • Cavity wall insulation is where the gap between walls is filled with foam, which reduces energy transfer by convection in the wall cavity
  • Loft insulation can reduce convection currents (a cycle where air particles are constantly heated, so rise, then cool and sink back down) being created in lofts
  • Draught excluders around doors and windows reduce energy transfers by convection
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22
Q

What is specific heat capacity?

A

The amount of energy required to raise the temperature of 1 kg of a substance by 1ºC

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23
Q

The formula for specific heat capacity is given (ΔE = mcΔθ). What is its symbol and unit?

A

Symbol: c

Unit: J / kg°C

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24
Q

Describe how you would find the specific heat capacity of a solid block of a material.

A
  • You’ll need a solid block of the material, with 2 holes for the heater and thermometer to go into.
  • Measure the block’s mass using a balance.
  • Wrap it in an insulating layer (decreases energy dissipated from block to surroundings).
  • Connect a heater to a power supply and ammeter, and place it into one of the object’s holes.
  • Place a thermometer into the other and measure the initial temperature of the block.
  • Set the power supply at 10V, then turn it on and immediately start a stopwatch.
  • The current transfers energy to the heater’s thermal energy store, which is then transferred to the object’s.
  • The ammeter reading should remain constant.
  • Measure the temperature on the thermometer every 30 seconds. Turn off the power when you have 10 readings.
  • Find the energy transferred to the heater at each reading using the formula E = VIt (bc E = Pt and P = VI).
  • Assuming all the energy transferred to the heater was transferred to the block, find the SHC using the rearrangement c = ΔE/mΔθ.
  • The plotted relationship between energy transferred and temperature would be directly proportional
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25
Q

Describe how you could investigate the effectiveness of different insulators.

A
  • Boil water in a kettle and use a balance to pour a set mass into a beaker.
  • Use a thermometer to measure the initial temperature.
  • Seal the beaker with a lid and use a stopwatch to leave it for 5 minutes.
  • Remove the lid and measure the water’s final temperature.
  • Pour away the water; allow the beaker to cool to room temperature.
  • Repeat steps 1-4 (use same mass of water each time!), wrapping the beaker in a different material (foil, newspaper, bubble wrap) each time.
  • The most effective insulator is that which reduces the temperature difference by the largest degree.

This investigation could be modified to instead test how the thickness of an insulator affects heat loss

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26
Q

What are non-renewable energy resources?

A

Non-renewable energy resources are ones that cannot be replenished as they are used up. They usually do damage to the environment

27
Q

Specifically what are non-renewable energy resources?

A

They are nuclear fuel (uranium and plutonium) and fossil fuels (natural resources that form underground over millions of years, typically burnt to provide energy). The three main ones are coal, oil and natural gas

28
Q

Non-renewables provide most of our energy. Why?

A

They are reliable. There is enough fuel to meet current demand, and they are extracted at a fast enough rate that power plants always have fuel in stock, so they can respond quickly to changes in demand

29
Q

What are the pros of fossil fuels?

A
  • Reliable.
  • Enough to meet current demand and respond to changes in demand.
  • Cost effective: while the setup costs of power plants are high, running and fuel extraction costs are fairly low
30
Q

What are the cons of fossil fuels? Give at least three.

A
  • Finite/non-renewable.
  • They release CO2 into the atmosphere when burned, adding to the greenhouse effect and global warming.
  • Power plants ruin the view.
  • Burning coal and oil releases sulfur dioxide, causing acid rain. Reduced by taking sulfur out before combustion.
  • Coal mining, especially open cast, ruins the landscape.
  • Oil spillages cause serious environmental problems
31
Q

What are the pros of nuclear power?

A
  • Reliable.
  • Enough to meet current demand.
  • Power plants can respond to changes in demand
32
Q

What are the cons of nuclear power? Give at least three.

A
  • Finite/non-renewable
  • Power plants ruin the view.
  • Nuclear waste is dangerous and hard to dispose of.
  • Fuel is relatively cheap, but overall cost of nuclear power is high due to cost of power plants and final decommissioning.
  • Nuclear power carries the risk of a major catastrophe
33
Q

What are renewable energy resources?

A

Natural energy sources that will never run out if we replenish them as they’re used. Most of them do damage to the environment, but less than non-renewables do

34
Q

Why don’t renewables provide the majority of our energy?

A
  • They aren’t very efficient.
  • They are unreliable; they depend on the weather.
  • They often can’t respond to changes in demand
35
Q

What are all the types of renewable energy resources?

A
  • Solar
  • Wind
  • Water waves
  • Hydroelectricity
  • Biofuel
  • Tides
  • Geothermal
36
Q

What are the uses of non-renewable energy resources in transport?

A
  • Petrol and diesel powered vehicles use fuel from oil
  • Coal is used in old-fashioned steam trains to boil water and produce steam
  • Electricity is used to power vehicles and can be generated from non-renewable resources
37
Q

What are the uses of renewable energy resources in transport?

A
  • Vehicles that purely run on biofuels

- Electricity is used to power vehicles and can be generated from renewable resources

38
Q

What are the uses of non-renewable energy resources in heating?

A

-Natural gas is the most widely used fuel for heating homes in the UK. It’s used to heat water which is pumped into radiators, and to cook food. -Coal is commonly burnt in fireplaces. -Electric heaters can use energy generated by non-renewables

39
Q

What are the uses of renewable energy resources in heating?

A

-Ground source heat pumps use geothermal energy resources to heat buildings. -Solar water heaters use the sun to heat water, which is then pumped into radiators. -Electric heaters can use energy generated by renewables, or heat generated by burning biofuels

40
Q

What are the pros of tidal power?

A
  • No pollution.
  • Initial costs are moderately high, but no fuel costs and minimal running costs.
  • Reliable; tides happen twice a day without fail and always around the predicted height.
  • Has the potential for generating a significant amount of energy
41
Q

What are the cons of tidal power?

A

• Prevents boat access.

  • Spoils the view.
  • Alters the habitats of wading birds, sea creatures and beasties that live in the sand.
  • When tides are lower (neap tides), significantly less energy is supplied.
  • Tidal barrages don’t work when the water level is equal on either side of the barrage- happens 4 times a day.
  • Can only be used in some estuaries
42
Q

What are the pros of solar power?

A
  • Causes no pollution (apart from manufacturing panels). - Aside from the initial costs, energy is free and running them costs very little
  • Reliable source of energy, especially in sunny places
43
Q

What are the cons of solar power?

A
  • Panels require a lot of energy to manufacture
  • They only work in the daytime
  • Power output cannot be increased when there is extra demand
  • They can’t produce as much energy as other non-renewable sources
44
Q

What are the uses of solar energy?

A

Tends to be on a small scale:

  • Charging calculator and watch batteries which don’t require much energy
  • Used in remote places where there’s not much choice
  • Powering road signs and satellites
45
Q

What are the pros of wave power?

A
  • No pollution
  • Initial costs are high, but no fuel costs and minimal running costs
  • Useful way to generate energy on a small scale, on small islands
46
Q

What are the cons of wave power?

A
  • Disturbs the seabed and habitats of marine animals.
  • Spoils the view.
  • Hazard to boats.
  • Can’t respond to changes in demand.
  • Unreliable; waves tend to die out when the wind drops
47
Q

Where are wave and wind turbines located?

A

Wave: around the coast. Wind: exposed places, e.g. the coast or on moors

48
Q

What are the pros of wind power?

A
  • Causes no pollution (apart from manufacturing)
  • No fuel costs and minimal running costs
  • No permanent damage to the landscape
49
Q

What are the cons of wind power?

A
  • Production costs are quite high.
  • They spoil scenery; a lot of them are needed to replace one coal power station.
  • They can be very noisy.
  • Dependant on the weather.
  • Power output cannot be increased with demand
50
Q

Where and how is geothermal energy sourced?

A

Geothermal power is harnessed from underground stores of thermal energy. The source of much of the energy is the decay of radioactive elements (e.g. uranium) deep inside the Earth

51
Q

How is geothermal energy used?

A

It can be used to generate electricity or heat buildings directly

52
Q

Where is it possible to harness geothermal energy on a large scale?

A

In volcanic areas or where hot rocks lie close to the surface

53
Q

What are the pros of geothermal power?

A

-Free. -Reliable. -Does little damage to the environment

54
Q

What are the cons of geothermal power?

A

-There aren’t very many suitable locations for power plants. -The cost of power plants is high compared to the amount of energy they produce

55
Q

What reduces the effect of hydroelectric power on humans?

A

Putting them in remote valleys, although this still affects animals

56
Q

What are the pros of hydroelectric power?

A
  • No pollution
  • Initial costs are high, but no fuel costs and minimal running costs
  • It can provide an immediate response to an increased demand for electricity
  • Useful way to generate electricity on a small scale in remote areas
57
Q

What are the cons of hydroelectric power?

A
  • Flooding of valleys destroys habitats, causes the loss of villages, and causes vegetation to rot, releasing methane and CO2
  • Reservoirs can look ugly when they dry out
  • Unreliable; depends on the weather and is redundant during droughts
58
Q

What are biofuels?

A

Fuels taken from [recently] living materials, e.g. plant products and animal waste.

  • They can be solid, liquid or gas
  • They can be burnt to produce electricity, or run cars, in the same way as fossil fuels
59
Q

What are the pros of biofuels?

A
  • They can be carbon neutral (fuels that take in as much CO2 from the atmosphere as is released when they are burnt)
  • Fairly reliable; crops don’t take long to grow and different ones can be grown all year round
  • Can be stored for when needed to accomodate for increases in demand
60
Q

What are the cons of biofuels?

A
  • They can’t respond to immediate energy demands (but they can be stored for when needed).
  • The cost of refining biofuels is very high.
  • Growing crops specifically for biofuels risks leaving a lack of space and water to meet demands for food crops.
  • Causes deforestation; many populations have lost their natural habitats as a result.
  • The decay and burning of forest vegetation also increases CO2 and methane emissions
61
Q

Describe the trends in use of energy in the UK over time

A
  • Over the 20th century, there was a high increase in energy use as people began to use electricity for more things
  • Since the beginning of the 21st century, energy use has been slowly decreasing as appliances have been made more efficient and people have been pushed to be more careful with energy use in the home
62
Q

Why do people want to use renewable energy resources?

A

-Fossil fuels are damaging to the environment. -People and governments are becoming increasingly eager to get used to using renewables before non-renewables eventually run out

63
Q

What factors limit the use of renewables?

A

Reliability, money and politics

GCSE Physics (8 decks)

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