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

I put sealed in glass and stored under water

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 = 52.5jG.D.P = energy transferred, so 53.5 = 1/2x3.5kgx(velocity)^2Rearrange to get 30 = velocity ^2Velocity = 5.48m/s

2 (a) (i) around 12.5 seconds
(ii) 6.5 m/s
(b) (i) (I think this was where it was) The top tick box (can't remember what it said though)
(ii) Because it increases the current in the wire (I have a feeling this is wrong)
(c) reaction
(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 marker
-in a collision, the car comes to a stop very suddenly
-change in momentum = force x time for which the force acts, therefore as the change in momentum is constant and can't be changed, 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.

5 (a) Electromagnetic induction
(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

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

7 Resistance in parallel wires 6 marker
-the results show a negative correlation, as the number of wires increases, the resistance in the wires decreases
-really need more points as I can't remember mine!!

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

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
(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.
(c) line drawn from beta to second box down
line drawn from gamma to top box
(d) 4,500,000,000 J
(e) Is this the Eve and Ben question?
(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.

10 I think this was the irradiated vegetable 6 marker
-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 unsourced because the food is not radioactive, therefore she cannot become contaminated by eating the vegetables as she is not ingesting radiation
-any more points needed?

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

Anyone else give their answer to the nuclear energy question in standard form? I put 4.5x10^9 but i guess it should be okay

Yasss! Finally an OCR 21st century science mark scheme!
So many silly mistakes. On one I was like "lemme put 0.2a, but 0.8 looks better," then I was like "Eve seems right but Abe is such a cool name, so I putting Abe."

But I imagine the grade boundaries for all three sciences are going to be higher.

I actually want to cry, because of this and P123 I don't think I've got my target (an A*)

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 = 52.5jG.D.P = energy transferred, so 53.5 = 1/2x3.5kgx(velocity)^2Rearrange to get 30 = velocity ^2Velocity = 5.48m/s

2 (a) (i) around 12.5 seconds
(ii) 6.5 m/s
(b) (i) (I think this was where it was) The top tick box (can't remember what it said though)
(ii) Because it increases the current in the wire (I have a feeling this is wrong)
(c) reaction
(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 marker
-in a collision, the car comes to a stop very suddenly
-change in momentum = force x time for which the force acts, therefore as the change in momentum is constant and can't be changed, 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.

5 (a) Electromagnetic induction
(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

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

7 Resistance in parallel wires 6 marker
-the results show a negative correlation, as the number of wires increases, the resistance in the wires decreases
-really need more points as I can't remember mine!!

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

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
(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.
(c) line drawn from beta to second box down
line drawn from gamma to top box
(d) 4,500,000,000 J
(e) Is this the Eve and Ben question?
(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.

10 I think this was the irradiated vegetable 6 marker
-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 unsourced because the food is not radioactive, therefore she cannot become contaminated by eating the vegetables as she is not ingesting radiation
-any more points needed?

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

Does anyone know where the question with Ben and Eve was?

Thanks so much for this, really feel like we are lacking in mark schemes for OCR! Thought this test was a blessing after that awful P1-3 test (in my opinion).
This this is missing the question about how high level waste is disposed.
I put sealed in steal and glass canisters and then cooled, followed by being stored underground.

The guy who said "The temperature must have been constant" (I think Dan?) was the first answer, the "who is drawing a valid conclusion from this data" question.

The second one, the guy saying "this is because ____(I can't remember)" was Ben I think, for the "who is providing an explanation for this data" question.

Ye, the 6 markers were pretty generous in this test.

I know woo!
I made the odd couple of errors too - hahaha I wouldn't really class Abe as a cool name but whatever floats your boat apparently loads of people put 0.8, how did that answer even come about?

Lol @ that six marker about seatbelts and airbags, it was almost exactly the same question as in one of the past papers.

Also, I'm pretty sure the question about GPE of the box and tins was literally the same question as one in a past paper. Like, the wording was different, but the values they gave you were all the same and the answer was the same.

I know - I was shocked to see a 6 marker so similar to one id done before! I completely ruled out car safety as a 6 mark question tbh

I can't believe I read that question wrong - it was so easy as well. Can you get method marks in science like you can in maths? Haha

I think grade boundaries will be around 38-42 for this paper for an A*

I don't even know. I had 0.2 first then I doubted myself. There was a similar question in last year's paper and I flopped that to.
Parallel and series circuits will be the death of me.
P7 is going to be a killer. I have only one one past paper w/ the class and gave up. I'm fine with science questions but application questions killlllll.

You can! And they're often incredibly easy to get, like getting a mark for just writing down a formula. On three mark questions if you do everything right but make a simple mistake like missing off a 0 or not converting the units, then you'll usually get 2 marks.

for 2(b)(i) the top tick box was about the graph of the lorry. it said 'speed increases, then decreases until the lorry becomes stationary.'

I put mine in standard form too, but I got the wrong answer (I somehow wound up with 4.5x10²⁵!! )
I think you'll be fine in standard form


I know woo!
I made the odd couple of errors too - hahaha I wouldn't really class Abe as a cool name but whatever floats your boat apparently loads of people put 0.8, how did that answer even come about?


Aw no! I'm sure you didn't do badly - a lot of people did find the exam quite tricky while others found it really nice. So I think the boundaries will be average really - if you're predicted an A* then I'd say you're capable of getting it still are you doing triple? Cause don't forget there's always P7!