(Original post by ihatehannah)
1. Frequency ( 1)
2. Echoes (1)
3. spread out, same as (2)
b) vibrations are parallel to the direction of energy transfer (2)
4. Expensive as National Grid is a long distance away from rural areas (1)
constant supply, little variation in output
£30k cheaper than wind turbine
doesn't produce as much noise as wind
could ruin ecosystem by preventing free movement of fish
May need maintenance unlike wind
Lower power output - 8W compared to 10W
Wind - ADVANTAGES
higher average output
Needs little maintenance
Wind speeds vary, meaning there could be times of under- or oversupply
Costs 50k, 30k more than HEP (6)
5. inefficient as less or little energy used to heat food as heat is lost as infrared radiation to the surroundings(2)
uses of infrared(1) : remote controls, optical fibres
uses of microwaves(1): mobile phones, satellites
b) properties of microwaves and infra red radiation (2): can diffract, can refract, travel same speed in vaccuum, both transverse waves, can be reflected transverse• same speed (through air)• can be reflected• can be refracted• can be diffracted• can be absorbed• transfer energy• can travel through a vacuum• can be polarised• show interference
calculation questions, 340 m/s for first one (2) then 78 degrees(3) , then 6.4 watts(2) then 0.07 degrees/s (2) efficiency question was 0.48 W (2)
6. Fins increase surface area and black matt a are good absorbers of heat (2)
7. cosmic microwave background radiation (1)
b) provides evidence for the big bang theory (1)
10. They keep costs as low as possible as efficiency does not increase as much but the cost goes up rapidly , ( give example and data figures to secure the marks) (2)
11. why france will still use nuclear power(2) : cost of electricity is cheaper(1) and produces much more electricity(1) , produces no greenhouse gases like co2(1)
12. Disadvantages of nuclear power stations(2): raw materials are non- renewable, high decommissioning costs, produces radioactive waste.
13. factors that affect rate of energy transfer of mug(2): room temperature, surface area , how shiny it is( not sure about this one) and colour of the mug
b) particles gain kinetic energy and collide more frequently, passing on their extra kinetic energy to other particles .(2)
c) how is a convection current formed in the mug(4): liquid at the bottom is heated and particles gain kinetic energy and move away from each other, this makes the liquid less dense , causing it to rise and displace the denser colder liquid at the top , the denser particles then fall and is heated again.
14) control variable for the investigation measuring rate of evaporation (1) : same beaker or same type of beaker, same position in the room., same thermometer .
b) why is the data logger better(2): more accurate (1) , easier to read(1) , more precise (1)
15 relationship of the graph comparing 3 types of beakers and their rate of evaporation(1): as time increases, rate of evaporation decreases.
b) Beaker A(1) gradient of the line is the lowest and the final temperature is the highest of em all
c) If investigation was repeated with lower volume , what effect would it have(1) : rate of evaporation will be higher (1)
Why evaporation causes temperature to decrease (3): particles with enough kinetic energy and travelling in the right direction will escape the liquid and evaporate and take their kinetic energy with them , which means average kinetic energy of particles in liquid is lower and thus temperature is lower.
16) why a vacuum reduces energy transfer (2) : no particles so stops energy transfer by conduction , convection and radiation