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OCR 21st Century Science Physics P4 P5 P6 *Unofficial Mark Scheme 2016*

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Original post by Ben.M
Well after that it seems you did learn :smile:

Well it was the right method at least, so you might get some marks for that, hopefully :smile:


Ah yeah true :smile:

Yeah exactly - hopefully the marker is feeling generous haha
Reply 81
Original post by NiamhM1801
Ah yeah true :smile:

Yeah exactly - hopefully the marker is feeling generous haha


My physics teacher marks GCSE papers and he's really nice so maybe others are too
Reply 82
Does anyone know the marks for the questions ?
Original post by Ben.M
My physics teacher marks GCSE papers and he's really nice so maybe others are too


Hope so!
Original post by Liana _F
Does anyone know the marks for the questions ?


Not really, I'd need a copy of the paper for that tbh
Original post by karen0217
That's wrong m8. Beta only goes through aluminium (which would be one of the boxes at the bottom) and gamma passed through both lead and aluminium so it was the last one.


No no no, beta is STOPPED by aluminium - so it can only pass through card
Gamma is STOPPED by lead, so it can only pass through card and aluminium
Original post by karen0217
That's wrong m8. Beta only goes through aluminium (which would be one of the boxes at the bottom) and gamma passed through both lead and aluminium so it was the last one.
No you're wrong m8 look in your physics books
Reply 87
Thank you so muxh for this, I could help you if you make ones for the 7s?
Original post by LokiiR
Thank you so muxh for this, I could help you if you make ones for the 7s?


Aw you're welcome, and yes that would probably be very helpful!!
I'm usually incredibly pushed for time in science papers so rarely have the chance to look back through my answers - today was a bit of a rarity :colondollar:, but since this has been quite popular I'll definitely try to really learn the content well so I can get the paper done and checked in 50 to memorise my answers (and the question order next time!!!)
This paper was dreadful, I thought that it completely ruined my physics grade and I was very worried. After reading this unofficial mark scheme however, it has definitely improved my mood, I did a lot better than I thought :smile: I definitely lost quite a few marks but I think there's a fair possibility that I still got an A* on this paper :biggrin:
Original post by DavidL2000
This paper was dreadful, I thought that it completely ruined my physics grade and I was very worried. After reading this unofficial mark scheme however, it has definitely improved my mood, I did a lot better than I thought :smile: I definitely lost quite a few marks but I think there's a fair possibility that I still got an A* on this paper :biggrin:


Now that's what we like to hear!! :biggrin:
Sorry to see that you found the paper hard though, although the fact that you still did well shows that you're obviously very capable!
Don't worry, everyone loses marks (well, except those robots who get 100% :tongue:) and you can still very comfortably get an A* by losing quite a considerable number of them!
I hope you get your A* :biggrin:
Original post by NiamhM1801
Now that's what we like to hear!! :biggrin:
Sorry to see that you found the paper hard though, although the fact that you still did well shows that you're obviously very capable!
Don't worry, everyone loses marks (well, except those robots who get 100% :tongue:) and you can still very comfortably get an A* by losing quite a considerable number of them!
I hope you get your A* :biggrin:


I wish you the best of luck as well :smile:
Original post by Ben.M
Change in GPE = Weight x Vertical Height Difference

You were given a 1.5m high shelf, a box with a mass of 3.2kg and a weight of 32N

So the GPE was 32 x 1.5, which equals 48

2KE/Mass = Velocity^2

48 x 2 = 96 so 96/3.2 = 30

Square root of 30 rounded to 5.5 for 2 d.p.

That's how I did it, not sure if it's right


Thank you :h:
Reply 93
Original post by florahill
Thank you :h:


You're very welcome, did it all make sense? :smile:
Mark per question, soon to be completed?
Reply 95
The formula for the velocity of a falling object is sqrt(20h)
Posted from TSR Mobile

For 9a do you think I'll still get marks for source B?
Original post by NiamhM1801
1 (a) (i) 22N
(ii) 11 J
(iii) conservation of energy is the idea that energy is never created or destroyed, only transferred or converted. It applies to Roy because his kinetic energy was converted into waste heat energy through conservation.
(b) 5.48 to 2dp - working below
35nx1.5m = 52.5j
G.D.P = energy transferred, so 53.5 = 1/2x3.5kgx(velocity)^2
Rearrange to get 30 = velocity ^2
Velocity = 5.48m/s

2 (a) (i) around 12.5 seconds
(ii) 6.5 m/s
(b) The top tick box, "speed increases, then decreases until the lorry becomes stationary" (1 mark)
(c) Reaction (1 mark)
(d) Because the forces are acting on different objects. The weight is acting on the road by the lorry and the reaction is acting on the lorry by the road.

3 Car crash seat belt and air bag (6 marks)
-in a collision, the car comes to a stop very suddenly
-change in momentum = resultant force x time for which the force acts, therefore as the change in momentum is constant and can't be changed, and as the time is very small, the resultant force is very large
-therefore passengers get injured because there is a large force acting on them, which causes a lot of pressure on the body in a short space of time.
-seat belts are slightly elastic so they stretch slightly. This means that, in a crash, the time taken for the body to stop moving is increased, so the force on the chest is reduced.
-air bags are released. Passengers' heads collide with these instead of the windscreen or dashboard, both of which are hard surfaces. As airbags are soft, they increase the amount of time taken for the passengers' heads to stop moving, so force to the head and neck is reduced.
-by reducing the amount of force, the pressure which the body undergoes is reduced, and so the risk and severity of injury are reduced significantly.

4 Explain how a transformer induces a voltage across the secondary coil: There is an alternating voltage on the primary coil which leads to an alternating current in the coil. This alternating current produces an alternating magnetic field in the iron core which induces an alternating voltage in the secondary coil. (3 marks)

5 (a) Electromagnetic induction (1 mark)
(b) You could have said a few for this one: putting the opposite pole of the magnet in (ie south instead of north), spinning the magnet, taking the magnet out (1 mark)
(c) Because it increases the size of the voltage (and therefore current) in the wire. (1 mark)

6 (a) Graph C (the one that looks like a sin graph) (1 mark)
(b) Iron (1 mark)

7 Resistance in parallel wires (6 marks)
-the results show a negative correlation, as the number of wires increases, the resistance in the wires decreases.
- increasing the number of pathways means the current gets shared, and therefore it is less in each wire
- this therefore reduces the resistance
- she could improve by using a wider range and more intervals to help get a clear trend
- she could use a different set of wires (possibly different length or width wires as both of these factors affect resistance)

8 If I remember rightly these were the calculation ones.
(a) (i) 5 Ω (1 mark)
(ii) 0.5 V (1 mark)
(b) (i) 1.5 V (1 mark)
(ii) 0.2 A (1 mark)

9 (a) Source C because:
- gamma radiation so it leaves the body quickly
- half life of around 1 hour so the exposure time is quite short and damage is limited (3 marks)
(b) Alpha radiation can't be detected by the badge because it is stopped by all 3 materials so can't pass through any of them. (2 marks)
(c) line drawn from beta to second box down
line drawn from gamma to top box (2 marks - 1 mark for each line)
(d) 4,500,000,000 J (or 4.5x10⁹ J)
(e) Eve, Ben (2 marks, 1 for each correct)
(f) He thinks that the perceived risk is higher than the statistical/calculated risk because he has no control over the plant, he doesn't know how it works and so might seem dangerous to him, past nuclear disasters, media and can't see radiation. (3 marks)

10 Irradiated vegetables (6 marks)
-irradiation means being exposed to ionising radiation without coming into direct contact with the source.
-irradiation is used on vegetables to sterilise them - ionising gamma radiation kills all the microbes on the food so it's safe to eat and has a long shelf life (no bacteria exist to grow as mould on it for a while)
-because irradiation doesn't involve contact with the source, the ionising effects stop as soon as the vegetables are removed from the source
-Donna's concerns are unfounded because the food is not radioactive, therefore she cannot become contaminated by eating the vegetables as she is not ingesting radiation

? Somewhere in the paper there was the question "how is high level radioactive waste dealt with?" But I don't know where it was: it is stored in glass and steel canisters in water for up to 50 years to cool, before being moved to more permanent storage (burial). (2 marks)

Feel free to add things, or change something you believe is wrong as I am in no way saying that my answers are definitely correct!

I thought I'd make a mark scheme because there have been an annoying lack of them for this board - and I know they're highly sought after. So enjoy! :smile:

Great set of answers but for the question about why the two forces aren't an interaction pair, you've said the forces act on different objects. However my OCR physics textbook states the forces are meant to act on different objects.
What I mentioned in my answer was the fact the lorry was stationary. This meant the force pairs here didn't have an overall effect or some sort of movement- something you would expect from balanced forces. Apart from supporting the weight, it has no real function.
I might not be fully right but just I would point out what was said in the textbook :smile:
Original post by MezmorisedPotato
Great set of answers but for the question about why the two forces aren't an interaction pair, you've said the forces act on different objects. However my OCR physics textbook states the forces are meant to act on different objects.
What I mentioned in my answer was the fact the lorry was stationary. This meant the force pairs here didn't have an overall effect or some sort of movement- something you would expect from balanced forces. Apart from supporting the weight, it has no real function.
I might not be fully right but just I would point out what was said in the textbook :smile:


Thank you :smile:

Hm yeah, bitesize says the same thing :s-smilie:
Ah - that's sounds about right, I guess for something to interact one of them needs to be moving. I'll change it as your answer is probably better than the one I've put down. That must have been why loads of people had a problem with that question, I just assumed they had to act on the same object.
Original post by thomas-cowley
Posted from TSR Mobile

For 9a do you think I'll still get marks for source B?


I think you could get 1 mark, as the half life is roughly one hour.
However source B was alpha radiation, which as in the picture you've attached, shouldn't be used for tracers.

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