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# 2016 AQA Physics Unit 1 - Unofficial Mark scheme watch

1. Will I get 48w for the correct answer
2. (Original post by Mahrez)
The comparision one is to get same efficnetcy as A you need twice of C which cost 4 times less
Buying 8 solar cells of C has a greater output than 1 of A
Exactly what i put and i also put 8 solar cells would total up to 80% efficiency much more than solar panel A
3. (Original post by PrinceKian)
Well the energy was 46,200 and the time was two hours, and you had to convert that to seconds, so it ended up being 46,200/7200 which equals 6.4
I forgot to convert it to seconds - would I still get 1 mark?
4. (Original post by SunnyBoys)
Surely if you decrease volume, there is less surface area, so there is a slower rate of evaporation.
That's what I thought but everyone's saying its wrong

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5. (Original post by CaSama9)
Exactly what i put and i also put 8 solar cells would total up to 80% efficiency much more than solar panel A
8 solar cells doesnt total up to an efficentcy of 80% it stays at 10%
6. (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
renewable resource
doesn't produce as much noise as wind
No CO2

could ruin ecosystem by preventing free movement of fish
May need maintenance unlike wind
Lower power output - 8W compared to 10W

higher average output
Needs little maintenance
renewable resource
Easily expanded
No CO2

Eyesore
noise pollution
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
Wouldn't you say the vacuum contains air which is a good insulator and poor conductor therefore reducing the rate of energy transfer.
7. (Original post by Mahrez)
8 solar cells doesnt total up to an efficentcy of 80% it stays at 10%
but you can get more power by using 8 rather than solar panel a right?
8. (Original post by Snoozinghamster)
Same. Totally forgot about the conversion! Blanked on joules etc!
What were the figures does anyone know????

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9. (Original post by CaSama9)
but you can get more power by using 8 rather than solar panel a right?
Yep more power output
Wouldn't you say the vacuum contains air which is a good insulator and poor conductor therefore reducing the rate of energy transfer.
this is incorrect as a vacuum has no particles, thus no air particles.
11. (Original post by ihatehannah)
this is incorrect as a vacuum has no particles, thus no air particles.
Oh alright,well I lost 2 marks then
12. Would a control variable for the investigation not be concentration?

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13. (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
renewable resource
doesn't produce as much noise as wind
No CO2

could ruin ecosystem by preventing free movement of fish
May need maintenance unlike wind
Lower power output - 8W compared to 10W

higher average output
Needs little maintenance
renewable resource
Easily expanded
No CO2

Eyesore
noise pollution
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
I only put background radiation for Q7, will i still get the mark?
14. (Original post by PrinceKian)
Erm I think you would get 1 mark out of two
How come only one though?
15. i dont get how increasing the volume has any effect on the RATE of evaporation ?
16. I've lost a solid 10 marks at least
17. (Original post by ihatehannah)
b) why is the data logger better(2): more accurate (1) , easier to read(1) , more precise (1)

I don't agree with your answer for 14)b). Using a thermometer is already accurate if it is used properly. There is nothing in a thermometer that could make it inaccurate and I'm not sure if precision counts here either. I would rather give the second mark for the datalogger preventing human error.

(Original post by ihatehannah)
16) why a vacuum reduces energy transfer (2) : no particles so stops energy transfer by conduction , convection and radiation
Also, vacuum reduces energy transfer by conduction and convection ONLY - NOT radiation.
18. (Original post by LaliG)
Do you remember how you got that answer?
Hi, I got that as well
I converted the 2 hours into seconds by doing 2 * 60 * 60 = 7200.
46200/7600 = 6.4166666666
rounded that to 6.42
19. (Original post by gy7gy7gy7)
Wasnt the answer that x100 because there was x100 at the end of the equation?
I'm fairly sure you did have to multiply 0.48 by 100 as that gives you the efficiency.
20. (Original post by dh12345)
i dont get how increasing the volume has any effect on the RATE of evaporation ?
I think it's to do with the surface area: volume ratio?
The greater the surface area in comparison to the volume, the greater the rate of energy transfer (ie. evaporation).
The surface area stays the same since they used the same apparatus, but the volume was decreased which had an effect on the ratio above
Spoiler:
Show
I think - just taking this from my biology adaptations revision

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