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AQA GCSE Combined science Physics trilogy 23rd May 2018 Unofficial Markscheme

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for the power question I did 15×10^6 ÷(10×60)= 25000w is that right
Sorry I don't remember the question numbers.

1.


A few answers I got were:

25000J
30 Coulombs for the second last 6 mark question.
19.1°C for the temperature after 30 minutes.
Uncertainty was 80 kg

Original post by Zak_I
Same here. If i'm correct, you use the formula p=I^2R and rearrange it so its I^2=P/R and then you square root the answer - giving me 2 C

Did you convert mins to seconds?
it was 25000w coz it's talking about the power I got the same as well except the 30 colomubs
Original post by ibbyakram16
for the power question I did 15×10^6 ÷(10×60)= 25000w is that right


Yeah I got that too.
Original post by zacdavis123
what did everyone get for the radius question on Magnesium? You had to measure it with a ruler?


I have no idea if this is right but I got 0.6cm for the radius of the small one and 3.8cm for the radius of Magnesium the big one, so I divided 3.8 by 0.6 to see how much smaller it was and then timesed that by the standard form number it gave you and I got 5x10(to the -11) but none of my friends got that so idk
Original post by lukeharris1505
I got 15 for the charge but I'm not sure that's right

correct
units were coulombs
Original post by Dil007
Sorry I don't remember the question numbers.

1.


A few answers I got were:

25000J
30 Coulombs for the second last 6 mark question.
19.1°C for the temperature after 30 minutes.
Uncertainty was 80 kg



What was the uncertainty question?
I got 30 for charge, you had to use the two equations “power = current^2 x resistance” and “charge = current x time” and rearrange them or whatever. Could someone explain the uncertainty question please? Just guessed it
Original post by Shidskdh
I have no idea if this is right but I got 0.6cm for the radius of the small one and 3.8cm for the radius of Magnesium the big one, so I divided 3.8 by 0.6 to see how much smaller it was and then timesed that by the standard form number it gave you and I got 5x10(to the -11) but none of my friends got that so idk


I did 6 rimes the radius of the small one to give the magnesium one. you had to work out the radius using your ruler
the ration from small to big was 6
I Did some of the magnesium question but not all of it
Original post by ibbyakram16
the practical question was easy was about density
you menna say
put the object on the balance and weigh it
then put it in a eureka can filled with water and place a measuring cylinder next to it the volume of the object is in the measuring cylinder plug the mass and volume into density equation and find out the density

how many marks do u think is that out of 6


The 6 mark questions are also marked on English, up to 2 marks, It should probably get full marks if your English was fine.
my ratio was 5.5
Original post by fishtosea
I got 30 for charge, you had to use the two equations “power = current^2 x resistance” and “charge = current x time” and rearrange them or whatever. Could someone explain the uncertainty question please? Just guessed it

range divide by 2
Q2) why do all elements have the same positive charge as other atoms of that element?

I put because atoms of the same element all have the same amount of protons, so therefore the same positive charge as each other because protons are positively charged. Anyone else put that?? Not sure if it’s enough to get the 3 marks
Original post by Zak_I
Same here. If i'm correct, you use the formula p=I^2R and rearrange it so its I^2=P/R and then you square root the answer - giving me 2 C


FINALY someone that used that formula. I got worried that I was the only one
Original post by ibbyakram16
my ratio was 5.5


my measurements were in .5 and .25
Original post by lukeharris1505
I got 15 for the charge but I'm not sure that's right

What calculation did you do, I got 30 and most other people did too? Do you remember if the question had a diagram?
it's out of 2 marks u would have got both of them
The charge question was 60C, the question gave you the power and resistance for one of the lamps, you had to work out the current (which was 0.5A) and then multiply by 2 because there were 2 lamps, then you had to multiply it by the time (60s) which gave you the final answer of 60C.
Formulas used:

- P= I(2)R, rearranged to give: I(2)=P/R. 12/3 gave 0.5A.
- Q = I x T, 1A x 60s gave 60C.
(edited 5 years ago)

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