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2016 AQA Physics Unit 1 - Unofficial Mark scheme

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Original post by milolj
I put that aswell i think its wrong


What I put 22
Reply 301
Ugh, I hate checking the unofficial mark scheme. Probably on around 45 marks at this rate :unimpressed:
For the CMBR question, I put 'cosmic BACKGROUND MICROWAVE radiation' Does it matter that I accidentally got the two middle words the wrong way round?
will you get marks if you cross out the right calculations and right answer?
Original post by Jem +
Ugh, I hate checking the unofficial mark scheme. Probably on around 45 marks at this rate :unimpressed:


can you get marks for putting the correct calculations and answers but crossing them out?
Question:
1) For the gas flame question i put: because heat is lost to the surroundings as it is only concentrated on one section of the pan, and the efficiency is decreased because the flame also produces sound and light so not all of it is useful output
2) For the mug question what effects the rate of transfer i put: amount of coffee in contact with the mug and the temperature difference between the coffee and the mug

How many marks do you think i will get??
Original post by robert113
will you get marks if you cross out the right calculations and right answer?


You will probably only get 1 mark
Original post by B3ASTy
for the rural one could i have put that it would be expensive connecting to the national grid so the amount of electricity generated wouldn't be worth it?


For the diffraction filling in the gap question, the second one was not the same as. This is because, although diffraction occurs when the gap (insect) is the same size as the wavelength, maximum diffraction, which is what the question asked, occurs when the wavelength is longer in comparison to the insect.
Original post by Omz123
I misread question and added it to make 122
Prob get 2/3 marks...we messed up,last step


It's so annoying
Original post by Krish235
For the diffraction filling in the gap question, the second one was not the same as. This is because, although diffraction occurs when the gap (insect) is the same size as the wavelength, maximum diffraction, which is what the question asked, occurs when the wavelength is longer in comparison to the insect.


That's what I thought
Original post by Krish235
For the diffraction filling in the gap question, the second one was not the same as. This is because, although diffraction occurs when the gap (insect) is the same size as the wavelength, maximum diffraction, which is what the question asked, occurs when the wavelength is longer in comparison to the insect.


Bitesize:

a gap similar to the wavelength causes a lot of spreading with no sharp shadow eg sound through a doorway

a gap larger than the wavelength causes little spreading and a sharp shadow eg light through a doorway

For the speed I got 0.34m/s because the formula is speed(m/s)=frequency(Hz)x wavelength(m) so its 0.0136m X 25Hz=0.34m/s?
Original post by 11alexandru-kore
For the speed I got 0.34m/s because the formula is speed(m/s)=frequency(Hz)x wavelength(m) so its 0.0136m X 25Hz=0.34m/s?


You had to convert from kWh's or something. The symbols were wrong
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)

4b) ADVANTAGES
constant supply, little variation in output
£30k cheaper than wind turbine
renewable resource
doesn't produce as much noise as wind
No CO2

DISADVANTAGES
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
renewable resource
Easily expanded
No CO2

DISADVANTAGES
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) avoids human error (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.

For the specific heat capacity question alot of people wrote 122 degrees I got 78 degrees the same as you but are you sure it's right because it said final temperature.
Original post by AsiyaAden9879
For the specific heat capacity question alot of people wrote 122 degrees I got 78 degrees the same as you but are you sure it's right because it said final temperature.


it's 78, 100 percent.
Original post by AsiyaAden9879
For the specific heat capacity question alot of people wrote 122 degrees I got 78 degrees the same as you but are you sure it's right because it said final temperature.


Yes but the final temperature was lower than the initial, and the initial was 100, so the temperature wouldn't rise during evaporation
Original post by 11alexandru-kore
For the speed I got 0.34m/s because the formula is speed(m/s)=frequency(Hz)x wavelength(m) so its 0.0136m X 25Hz=0.34m/s?


I got that too.
Can someone explain the specific heat capacity question?
If the temperature change = after - before, then 22 = after - 100,
So before = 22 + 100 =122 degrees?
Original post by ProbablyJade
Bitesize:

a gap similar to the wavelength causes a lot of spreading with no sharp shadow eg sound through a doorway

a gap larger than the wavelength causes little spreading and a sharp shadow eg light through a doorway



Yes, but if the wavelength is bigger than the gap, then there's more diffraction than if the wavelength and the gap are the same size.
[QUOTE="11alexandru-kore;65168821"]
Original post by ProbablyJade
You had to convert from kWh's or something. The symbols were wrong[/ did 25 have Hz next to it?


I can't remember honestly, but i remember that in several of the questions you had to change the units

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