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iGCSE Physics > Energy Resources and Transfers > Flashcards

Energy Resources and Transfers Flashcards

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1
Q

State the 8 main stores of energy

A

-Chemical
-Gravitational
-Thermal
-Electrostatic
-Kinetic
-Elastic
-Magnetic
-Nuclear

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2
Q

Define conservation of energy

A

Energy cannot be created or destroyed, only change from one form to another.

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3
Q

What are the four main transfer types between energy stores?

A

-Mechanically (by force)
-Electrically (current flow)
-Heating (conduction, convection, radiation)
-Radiation (light and sound)

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4
Q

How can energy be changed through work done by forces?

A

A force converts energy mechanically by work done. Eg. If moving object is travelling upwards, its kinetic energy is converted to GPE by work done against its weight

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5
Q

A skateboarder starts at rest at the top of a hill, she pushes herself down a rough hill and comes to rest at the bottom. What energy changes take place?

A

-Start= GPE + Work by pushing herself
-Riding down =GPE→KE and friction
-All energy lost through heting the surroundings through the friction between the ground there is no KE and she’s at rest.

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6
Q

How can energy be transferred through electrical equipment?

A

Energy is stored as chemical in the battery. Then current converts chemical energy into other forms electrically.

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7
Q

State the equation used to calculate “efficiency”

A

Efficiency= useful energy/total energy x100

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8
Q

What changes are involved when a ball (initially stationary), rolls down a hill?

A

-GPE turns into KE as it rolls downwards
-The speed will increase

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9
Q

Define wasted energy

A

The energy that is not used up by the device for its desired purpose is the waste energy.

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10
Q

In which ways can thermal energy be transferred?

A

-Conduction
-Convection
-Radiation

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11
Q

Define conduction

A

When heat is transmitted in solids through collisions between neighboring atoms or molecules.

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12
Q

Define convection

A

Heat is transferred in gases and liquids by movement from hotter to cooler regions.

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13
Q

Define radiation

A

Energy that comes from a source and travels through space at the speed of light.

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14
Q

Explain how surfaces can be adjusted for heat transfer by radiation

A

-Black dull surfaces are good emitters/absorbers but bad reflectors of thermal radiation. White and shiny vice versa.

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15
Q

Define thermal conductivity

A

The thermal conductivity of a material is a measure of its ability to conduct heat.

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16
Q

How does the thickness of a building’s walls affect the rate of cooling?

A

The thicker the building walls are the further heat has to travel to escape, hence as you increase the thickness you decrease the rate of cooling

17
Q

How can you reduce unwanted energy transfer.

A

-Insulation in walls and ceilings.
-Double glazed windows
-Curtains

18
Q

Equation for the work done on an object

A

W = F x d

Work=Joules
Force=N
d=Metres

19
Q

Relationship between work done on an object and energy transfer?

A

W=∆E

20
Q

State the equation used to calculate the change in gravitational potential energy.

A

∆GPE = mxgx∆h

GPE=Joules
Change in vertical height=m

21
Q

Equation used to calculate kinetic energy.

A

KE= 1/2mv²

KE=Joule
mass=kg
speed=m/s²

22
Q

What is meant by power in physics

A

-Rate at which energy is transferred.
-Work done per unit of time

23
Q

State the equation used to calculate the power of a device

A

Power(Watts)=Work done(J)/Time (s)

W/PxT

24
Q

What is another way of describing a watt?

A

1 joule per second

25
Q

Describe the energy changes in a power station

A

-Heat energy released in the reaction (chemical, nuclear), is used to make steam
-Converted to kinetic energy as the steam moves the turbine
-More kinetic energy as the turbine movement moves the generator
-Electrical energy as the generator generates electricity

26
Q

What are the main energy sources that are available on earth?

A

-Fossil fuels
-Nuclear fuel
-Hydroelectricity
-The sun
-Geothermal resource
-The tides

27
Q

What is a non-renewable fuel?

A

A fuel that has limited supply and will eventually run out

28
Q

What is meant by a renewable energy source?

A

Sources that replenish themselves naturally and will not run out

29
Q

Give some examples of renewable energy sources

A

-Solar
-Tidal
-Waves
-Wind
-Geothermal
-Biomass
-Hydroelectric

30
Q

What are the benefits of using fossil fuels as an energy source?

A

-It doesn’t cost a lot to obtain the fuel
-It provides a lot of energy
-If there is a quick change in demand, fossil fuels can respond to that change quickly

31
Q

How is wind used as an energy source?

A

-Wind turns wind turbine blades
-Turbine turns generator, which causes electricity to be produced
-Initial store is kinetic energy of wind

32
Q

How does hydroelectric power produce energy

A

-Rainwater collects behind a dam
-When water is released, it is used to turn a turbine
-Turbine turns a generator which produces electricity
-Initial store is GPE

33
Q

What energy source uses light energy to create an electric current?

A

-Solar cells, Photovoltaic cells

34
Q

What are the advantages of tidal energy sources

A

-Do not produce greenhouse gases
-Reliable
-Cheap to run as tides are natural

35
Q

Disadvantages of hydroelectric power?

A

-Dam may cause flooding
-Cost a lot to install
-Cannot be used everywhere

36
Q

Why might people have problems with wind turbines?

A

-Lead to noise/visual pollution
-Can cause harm to bird flocks
-Take up large areas

37
Q

Advantages of solar panels?

A

-Dont cause damage to the environment
-Renewable
-Used in remote areas where other types of energy are less accessible

38
Q

What are the advantages of using nuclear energy for electricity production?

A

-Cheapest energy production per kWh
-Does not produce any greenhouse gas
-It is not location-specific. Can be used in most countries
-Not weather dependent therefore its reliable

39
Q

Disadvantages of using nuclear energy for electricity production?

A

-Produced nuclear waste which is radioactive and has a long half-life
-High commission fees for stations because they become radioactive
-Can be targets of terror attacks
-Risk of nuclear accidents

iGCSE Physics (8 decks)

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