physics p2, energy resources and energy transfer

Question 1

9 types of energy- CLENT KEGS

Answer 1

1- CHEMICAL
2- LIGHT
3- ELECTRICAL
4- NUCLEAR
5- THERMAL
6- KINETIC
7- ELASTIC POTENTIAL
8- GRAVITATIONAL POTENTIAL
9- SOUND

Question 2

what are chemical and potential forms of?

Answer 2

stored energy

Question 3

what’s the principle of the conservation of energy?

Answer 3

energy can never be created nor destroyed- it’s only ever transferred from one to another

Question 4

efficiency=

Answer 4

useful energy output/ total energy input

Question 5

no device is 100% efficient and…

Answer 5

…the wasted energy is always dissipated as heat

Question 6

electrical devices convert ELECTRICAL ENERGY->

Answer 6

sound
light
heat

Question 7

batteries convert CHEMICAL ENERGY->

Answer 7

electrical-> kinetic, heat, sound, light

Question 8

GPE and ELASTIC POTENTIAL always get converted into ->

Answer 8

KINETIC ENERGY

Question 9

how can heat be transferred?

Answer 9

by radiation, conduction or convection

Question 10

what is thermal radiation the transfer of?

Answer 10

heat energy by electromagnetic waves- objects are continually absorbing and emmiting heat radiation. an object that’s hotter than its surroundings emits more radiation than it absorbs and vice versa

Question 11

what is conduction?

Answer 11

in a solid: the process where vibrating particles pass on their extra kinetic energy to neighbouring particles. the vibrations are passed on to the near by aprticles

Question 12

what is convection?

Answer 12

where more energetic particles move from the hotter region to the cooler region- and take their heat energy with them

Question 13

how does an immersion heater work?

Answer 13

1) heat energy is transferred from the heater coils to the water by conduction
2) the particles near the coils get more energy so move faster- more distance between them so water expands and becomes less dense
3) this reduction in density means that hotter water tends to rise about the denser, cooler water
4) as the hot water rises it displaces the colder water making it sink to the heater coils.
5) this cold water is then heated by the coils and rises-cycle is continuous. you end up with convection currents going up round and down, circulating the heat energy through the water

Question 14

where is convection most efficient?

Answer 14

in roundish or squarish containers- allow convection currents to work best

Question 15

convection currents=

Answer 15

change in density

Question 16

radiator convection=

Answer 16

hot, less dense air rises- displaces cooler air, cooler air flows to replace it

Question 17

what is work done?

Answer 17

the energy transferred

Question 18

what happens when a force moves an object?

Answer 18

energy is transferred and work it done

Question 19

work done (J)=

Answer 19

force x distance

Question 20

what is power?

Answer 20

the rates of energy transfer or the rate of doing work

Question 21

power (W) or (J/s)=

Answer 21

work done/time

Question 22

kinetic energy gained=

Answer 22

GPE lost

Question 23

what are 4 non-renewable energy resources?

Answer 23

1) coal
2) oil
3) natural gas
4) nuclear fuels (uranium and plutonium)

Question 24

what are the energy transfers in a power station?

Answer 24

CHEMICAL ENERGY (fuel)–> HEAT ENERGY (steam)–> KINETIC ENERGY(turbine-> spins generator) –> ELECTRICAL ENERGY (generator-> national grid)

Question 25

what are the energy transfers in nuclear reactors?

Answer 25

NUCLEAR ENERGY-> HEAT ENERGY-> KINETIC ENERGY-> ELECTRICAL ENERGY

Question 26

energy transfers in wind farms?

Answer 26

K.E ->ELECTRICAL in moors, on coast, out at sea

Question 27

energy transfers in geothermal energy?

Answer 27

HEAT-> KINETIC-> ELECTRICAL - water is pumped in pipes down to hot rocks and forced back up due to pressure to turn a turbine drives a generator

Question 28

energy transfers in solar cells?

Answer 28

LIGHT ENERGY-> ELECTRICAL- generate direct current solar panels- black water pipes inside glass box- glass lets heat and light from sun in and absorbed by black pipes to heat up water cooking with solar power- use curved mirror to focus sun's light and heat same in solar oven-slow bulky and unreliable

Question 29

energy transfers in wave power?

Answer 29

K.E of waves-> ELECTRICAL ENERGY - lots of wave converters around the coast- up and down motion of tide drives a generator

Question 30

energy transfers of tidal barrages?

Answer 30

K.E -> ELECTRICAL big dams built across river estuaries with turbines in them. tide fills them to 7m and water is allowed through turbines which drives them on the way in and a generator

Question 31

energy transfers in hydroelectric power?

Answer 31

GPE-> KE-> ELECTRICAL- flooding of valley by building a dam- rainwater is caught and allowed out through turbines

Question 32

energy transfers of pumped storage?

Answer 32

GPE-> KE-> ELECTRICAL- storing spare energy for later use most large power stations have boilers which are kept running all night even when demand is low- surplus of electricity at night- storing energy for later use. pumps water up to a higher reservoir which can be released quickly during periods of peak demand to supplement the steady delivery from the big power stations.a way of storing energy that has already been generated

Question 33

what are the advantages of burning fossil fuels?

Answer 33

1) releases a lot of energy, relatively cheaply 2) energy from fossil fuels doesn't rely on the weather like lots of renewable energy= reliable 3) already lots of fossil fuel power stations so don't need to spend money on new technology

Question 34

what are the disadvantages of burning fossil fuels?

Answer 34

1) release CO2 into the atmosphere which contributes to global warming and climate change 2) burning coal and oil releases sulfur dioxide SO2, which causes acid rain- harms trees and soils having a huge affect on wildlife 3) they will eventually run out

Question 35

what are the advantages and disadvantages of nuclear power?

Answer 35

ADV: doesn't produce any of the greenhouse gases still plenty of uranium left in the ground DISADV: - nuclear reactors are expensiveto build and maintain - take longer to start up than fossil fuels - processing the uranium before can cause pollution - always a risk of leaks of radioactive material or a major catastrophe like at Chernobyl - radioactive waste - when too old and inefficient, nuclear power stations have to be decommissioned= expensive

Question 36

what are the advantages and disadvantages of wind farms?

Answer 36

ADV:- quite cheap to run - tough and reliable - wind is free - doesn't produce any polluting waste - renewable DISADV: - spoil the view - need 1500 wind turbines to replace 1 coal-fired power station- covers a lot of ground - noisy - wind isn't always strong enough to generate any power so impossible to increase supply when there's extra demand - expensive to set up especially out at sea

Question 37

what are the advantages and disadvantages of geothermal energy?

Answer 37

ADV: free, renewable, no real environmental problems DISADV: cost of drilling down several km - cost of building a power plant is often high compares to the amount of energy we get out of it - few places where this seems to be an economic option

Question 38

what are the advantages and disadvantages of solar energy?

Answer 38

ADV: - the Sun provides renewable energy source - energy is free and running costs are almost nil - no pollution - the cells can be linked to rechargeable batteries to create a system that can store energy during the day for use at night - good to power calculators or watches as don't use much energy - used in remote places where not much choice and in satellites DISADV: - used to generate on a small scale- individual homes - not practical or too expensive to connect them to the National Grid - solar cells can only generate enough electricity to be useful if they have enough sunlight- problem at night

Question 39

what are the advantages and disadvantages of wave power?

Answer 39

``` ADV: - no pollution -renewable -useful on small islands DISADV: spoiling the view -hazard to boats - fairly unreliable- waves die out when wind drops -initial coast are high -unlikely to provide energy on a large scale ```

Question 40

what are the advantages and disadvantages of tidal barrages?

Answer 40

ADV: -no pollution - renewable - tides are pretty reliable - no fuel costs and minimal running costs DISADV: prevent free access by boats, - spoil the view - alter the habitat of the wildlife - height of the wave is variable so lower tides will provide less energy than higher ones - initial costs are moderately high

Question 41

what are the advantages and disadvantages of hydroelectricity?

Answer 41

ADV: - renewable - no pollution - immediate response to increased demand. - reliable except in a drought DISADV: big impact on the environment due to flooding the valley- rotting vegetation releases methane and CO2 and possible loss of habitat for some species - look unsightly when they dry up - initial costs are high