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MAC short physics facts > Energy > Flashcards

Energy Flashcards

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1
Q

What are the 8 types of energy store?

A

chemical
kinetic
gravitational
elastic
thermal
magnetic
electrostatic
magnetic

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2
Q

What are the 4 methods of energy transfer?

A

Mechanically (whenever a force acts)
Electrically
By heating (conduction, convection, radiation)
by radiation of light and sound

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3
Q

Equation: Efficiency =

A

Efficiency = useful energy output / total energy input

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4
Q

What are the 3 methods of transfer of heat?

A

Conduction
Convection
Radiation

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5
Q

Describe conduction of heat.

A

Best in metals (as they have delocalised electrons)
Worse in air (particles long way apart)
Energy passed on by particles gaining energy and colliding with neighbouring particles to pass the energy along.

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6
Q

Describe convection.

A

Happens in liquids and gases
Region of air heated, particles move quicker, take up more space.
This less dense air rises
Cooler air is more dense and sinks
This forms a convection current

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7
Q

Describe radiation.

A

An electromagnetic waves that can travel in a vacuum
Shiny, white surfaces reflect radiation
Matt black surfaces absorb radiation so are the best emitters too

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8
Q

Describe the changes to radiation emitted is the surface becomes hotter.

A

More radiation emitted if the temp increases

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9
Q

Which 2 heat transfer types are prevented by cavity wall insulation?

A

conduction as air is trapped and air is a good insulator
convection as air is trapped and cannot form convection currents

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10
Q

How does a puffer jacket keep you warm?

A

trapped air stops heat transfer by conduction as air is a god insulator
trapped air also stops heat transfer by convection

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11
Q

Why wrap a marathon runner with a foil blanket at the end of the race?

A

shiny foil reflects the heat back to the runner preventing heat loss by radiation

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12
Q

Name the energy transfers when generating electricity by wind power.

A

kinetic energy store in the wind
transferred mechanically to
kinetic energy in the turbine
transferred electrically to peoples homes

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13
Q

Name the energy transfers when generating electricity by water power.

A

gravitational energy store in the water
transferred mechanically to
kinetic energy in the turbine
transferred electrically to peoples homes

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14
Q

Name the energy transfer when generating electricity using geothermal resources.

A

thermal energy store in the ground
transferred by heating to
thermal energy in steam
transferred mechanically to
kinetic energy store in the turbine
transferred electrically to our homes

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15
Q

Name the energy transfer when using solar heating systems.

A

energy transferred by radiation from the sun
thermal energy store in the solar heating panels

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16
Q

Name the energy transfer when generating electricity using solar cells.

A

energy transferred by radiation from the sun
transferred electrically to our homes

17
Q

Name the energy transfer when generating electricity using fossil fuels.

A

thermal energy store in the fossil fuels
transferred by heating to
thermal energy in steam
transferred mechanically to
kinetic energy store in the turbine
transferred electrically to our homes

18
Q

Name the energy transfer when generating electricity using nuclear power.

A

nuclear energy store in uranium nuclei
transferred by heating to
thermal energy in steam
transferred mechanically to
kinetic energy store in the turbine
transferred electrically to our homes

19
Q

Equation Work done = force x distance moved

A

Work done = force x distance moved

20
Q

How are work done and energy transferred related?

A

Work done = energy transferred

21
Q

Equation gravitational PE =

A

GPE = mgh

22
Q

Equation Kinetic energy =

A

KE = 1/2 mv2

23
Q

What is the principle of conservation of energy?

A

Energy cannot be created or destroyed only tranformed

24
Q

Fall a falling object, the energy transfer is ….

A

GPE lost = KE gained
mgh = 1/2 mv2

25
Q

For a car stopping, the energy transfer is …

A

KE lost = Work done by brakes
1/2mv2 = f x d

26
Q

Power =

A

Power = work done / time = energy tranfer / time
P = E/t

27
Q

Advantages and disadvantage of large scale electricity generation using wind

A

advantages:
renewable
no CO2 emmision so no green house gases
disadvantages:
unreliable as not always windy
location specific

28
Q

Advantages and disadvantage of large scale electricity generation using water

A

advantages:
renewable
no CO2 emmision so no green house gases
does not contribute to global warming

disadvantages:
unreliable as not always windy
location specific
can effect local habitat

29
Q

Advantages and disadvantage of large scale electricity generation using geothermal

A

advantages:
renewable
no CO2 emmision so no green house gases
so does not contribute to global warming
reliable

disadvantages:
location specific, eg Iceland due to needing thin crust

30
Q

Advantages and disadvantage of large scale electricity generation using solar heating systems

A

advantages:
renewable
no CO2 emmision so no green house gases
so does not contribute to global warming

disadvantages:
unreliable as require daylight so won’t work at night

31
Q

Advantages and disadvantage of large scale electricity generation using solar

A

advantages:
renewable
no CO2 emmision so no green house gases
so does not contribute to global warming

disadvantages:
unreliable as require daylight so won’t work at night

32
Q

Advantages and disadvantage of large scale electricity generation using fossil fuels

A

advantages:
reliable as can generate 24 /7
cheap to build

disadvantages:
CO2 emmision so green house gases given off
contributes to global warming
non renewable

33
Q

Advantages and disadvantage of large scale electricity generation using nuclear

A

advantages:
no CO2 emmision so no green house gases
so does not contribute to global warming
reliable as can generate 24 /7

disadvantages:
need to dispose of radiactive waste
dangers of melt down causing radiation leaks

MAC short physics facts (10 decks)

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