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Physics > Topic 1 - Energy > Flashcards

Topic 1 - Energy Flashcards

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1
Q

What are the 8 different energy stores?

A

thermal
kinetic
gravitaional potential
elastic potential
chemical
magnetic
electrostatic
nuclear

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2
Q

What are the four ways that energy can be transferred?

A

Mechanically, electrically, heating , radiation

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3
Q

WHat is a closed system ?

A

a system where neither matter nor energy can enter or leave
the net change in the total energy of a closed system is always 0

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4
Q

Describe the energy transfers when boiling water in a kettle.

A

energy is transfered electrically to the thermal energy store of the kettles heating element which transfers energy by heating to the waters thermal energy store.

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5
Q

When is kinetic energy transfered/ used?

A

in moving objects
when an object speeds up , energy is transfered to it.
when it slows down , energy is transferred away .

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6
Q

What is the equation for kinetic energy ?

A

E = 1/2 m v ^2
energy = 1/2 mass x velocity ^2

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7
Q

When in an object is there more gravitational potential energy ?

A

When the object is lifted high

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8
Q

What is the equation for gravitiaional potential energy ?

A

E = mgh
energy = mass x gravity x height

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9
Q

What is the link between kinetic and gravitational potentai lenergy >

A

energy lost from G.P .E store = energy gained in kinetic store

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10
Q

When is energy transfered to an objects elastic potential energy store?

A

WHen an object is stretched or squashed

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11
Q

What is the equation for elastic potential energy ?

A

E = 1/2 k x e ^2
energy = 1/2 spring constant x extension ^2

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12
Q

What is specific heat capacity?

A

the amount of energy needed to raise the temperature of 1 kg of a substance by 1 degree celsius

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13
Q

What is the equation for specific heat capacity?

A

^E = mc^0

change in thermal energy = mass x specific heat capacity x temperatue change

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14
Q

Describe how you would carry out an investigation to work out the specific heat capacity of a substance.

A

1) get a block of your chosen material with two holes in it.
2) place a heater connected to a power supply in one of the holes.
3) connect an ammeter to the power supply.
4) measure the mass of the block of material then wrap it in insulating material to reduce the energy transferred from the block to the surroundings.
5) add a drop of water in the other hole and place your thermometer inside,
6) measure the initial temperature of the block and set the potential different of the power supply to 10v .
7) turn on the power supply and start a stop watch .
take readings of the temperature and current every minute for ten mins.
8) when enough readings are collected, turn off the power supply then calculate the power supplied to the ehater using p = vi
9) use results to calculate specific heat capacity.

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15
Q

What is the conservation of energy principle?

A

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

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16
Q

what are the two equations for power?

A

power = energy transfered / time
power = work done / time

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17
Q

What is conduction ?

A

the process where vibrating particles transfer energy to neighbouring particles.

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18
Q

What is thermal conductivity?

A

a measure of how quickly energy is transferred through a material through conduction

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19
Q

describe how energy is transferred through a solid by heating.

A

the energy is transferred to the thermal store of the object,
the energy is shared across the kinetic energy store of the particles in the object,
the particles in the parts of the object being heated vibrate more and colliede with eachother.
these collisions cause enery ti be transfered between the particle’s kinetic energy stores.
the process continues throughout the object untill the energy is transfered to the other side of the object .

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20
Q

What is convection?

A

where energetic particles move away from hotter to cooler regions.

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21
Q

what state of matter does convection happen in?

A

liquid or gas

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22
Q

Describe how convection works.

A

energy is trasnfered by heating to the thermal store of the liquid or gas.
it is then shared across the kinetic energy store of the gas or liquids particles.
the particles move faster and the space between the individual particles increases.
this causes the density of the region being heated to decrease
the warmer and less dense region will rise above the denser cooler region.
if there is a constant heat sourcee , a convection current can be created

23
Q

Describe how radiators create convections currents.

A

energy is transferred from the radiator to the nearby air particles bu conduction.
the air by the radiator becomeswarmer and less dense.
the warm air rises and is replaced with cooler air.
the cooler air is then heated by the radiator.
at the same time, the previouslt heated airtransfers emergy to the surrounding .
it cools , beomces denser and sinks.
the cycle repeats cause a flow of air to cirsulate around the room

24
Q

Wht are the two ways that we can reduce unwanted energy transfers ?

A

lubrication and insulation

25
Q

How does lubrication reduce unwanted energy transfers?

A

reduce the frictions between objects’ surfaces when they move.

26
Q

How can we reduce energy losses through heating in a home?

A

cavity walls - inner and outer wall with an air gap in the middle , the air gap reduces ernergy transferred by conduction
cavity wall insulation - where the cavity wall is filled with a foam , reduce energy transferred by convection
loft insulation - reduce convection current in lofts
double glazed windows- have an air gap to prevent energy transfer by conduction
draught excluders around doors and windows- reduce energy transfers by convection

27
Q

Describe a method to investigate the effectiveness of materials as thermal insulators.

A

1) boil water in a kettle .
2) pour it in a sealable container e.g. a beaker and a lid. to asafe level .
3) measure the mass of the water in the container.
4) use a thermometer to measure the initial temperature
5) seal the container and leavr for 5 mins using a stopwatch
6) remove the lid and record the final temperature of the water.
7) pour away the water and allow the container to cool
8) repeat but wrap the container in different material
9) the lower the temp difference , the better the insulator.

28
Q

what is the equation for efficiency?

A

efficiency = useful output energy transfer/ total input energy transfer
efficiency = useful power output/ total power input

29
Q

What is a non renewable source?

A

energy sources that will run out one day

30
Q

What are the three main fossil fuels?

A

coal
oil
natural gas

31
Q

What are the different types of renewable energy resources?

A

the sun(solar)
wind
water waves
hydro-electricity
bio-fuel
tides
geothermal

32
Q

how are non renewable energy sources used for transport?

A

petrol and diesel powered vehicles use fuel created from oil.
coal is used in old fashioned steam trains to boil water to produce steam

33
Q

How are renewable energy sources used for transport?

A

vehicles that run on pure bio fuels or a mix of a bio fuel and petrol or diesel.

34
Q

how are non renewable energy resources used for heating?

A

natural gas is used to heat water which is then pumped into radiators thorughout homes.
coal is burnt in fireplaces.
electric heaters use electricity gernerated from non renewable energy resources

35
Q

how are renewable energy resources used for heating?

A

geothermal heat pump used geothermal energy resources to heat buildings.
solar water heaters work by using the sun to hreat water which is then pumped into radiators in the nbuilding.
burning bio-fuel or using electriicty generated from renewable resources can also be used for heating

36
Q

What are the benefits of wind power?

A

no pollution
no fuel costs
minimal running costs
no permanent damage to landscapess

37
Q

what are the disadvantages of wind power?

A

effect scenery/landscape view
noisy
no electricity porduced when the wind stops
high initial costs

38
Q

What are the advantages of solar cells/panels?

A

no pollution
low running costs
free energy
very reliable in sunny countries

39
Q

What are the disadvantages of solar cells/ panels?

A

generate electricity on a small scale
high initial costs
cannot increase power output when there is extra demand
only works in the sun or daytime

40
Q

What are the advantages of geothermal power?

A

free energy
reliable
does very little damage to the environment

41
Q

WHat are the disadvantages of geothermal power?

A

very few suitable locations for power plants.
cost of building a power plant is very high compared to the amount of energy it produces

42
Q

How do we get hydro-electric power?

A

requires the flooding of a valley by building a big dam.
water is allowed through turbines .

43
Q

What are the advantages of hydro-electric power?

A

there is no pollution
can provide an immediate response to an increased demand for electricity
no fuel costs
minimal running costs
usefull for generating electricity in remote areas
reliable except in times of drought

44
Q

What are the disadvantages of hydro-electric power?

A

negative impact on the environment
loss of habitat
destroy landscapes
high initial costs
flooding of the valley can lead to rotting vegetation which reelases methane and co2

45
Q

WHat are the advantages of wave power?

A

no pollution
no fuel costs
minimal running costs
usefull for small islands

46
Q

What are the disadvantages of wave power?

A

disturbs the seabed and habitats
spoils the view
hazard to boats
unreliable
high initial costs
produces little energy

47
Q

How do tidal barrages work?

A

a big dam is built across river estuaries, with turbines in them .
as the tide comes in it fill the estruary.
the water is then allowed out through the turbines at a controlled speed

48
Q

What are the advantages of tidal barrages?

A

no pollution
reliable(happen twice a day)
no fuel costs
minimal running costs
can generate a significant amount of energy

49
Q

What are the disadvantages of tidal barrages?

A

prevents feree acces by boats
spoils the view
alters habitats
high initial costs
amount of energy producs depends on the height of the tide

50
Q

What are the advantages of bio fuels?

A

supposedly carbon neutral
fairly reliable as crops take a relatively short time to grow and some crops can be grown all year round.

51
Q

What are the disadvantages of bio fuels?

A

cannot respond to immediate energy demands
cost to refine bio fuels is very high
requires large amounts of land
decay and burning of vegetation increases c02 and methane emmisions

52
Q

What are the advantages of non renewable energy resources?

A

reliable
can respond quickly to changes in demand
low running costs
fairly low extraction costs
cost effective way to produce energy

53
Q

What are the disadvantages of non renewable energy resouces?

A

will one day run out
release fossil fuels when burned which adds to the greenhouse effect
releases sulfur dioxide which causes acid rain
coal mining destroys the landscape
oil spillages cause environmental problems
nuclear waste is dangerous to get rid of

54
Q

Give reasons why we currently do not use more renewable energy resources in the uk.

A

building new renewable power plants costs a lot of money
energy providers are reluctant to do this especially when fossil fuels are so cost effective
cost of switching to renewable power with have to be paid by customers bill or taxes, some cant afford that
arguments over where to put new power plants
some renewable resources are not reliable
research on improving cost and reliability takes time

Physics (5 decks)

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