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# GCSE OCR Physics B P1P2P3 15 June 2016 UNOFFICIAL MARK SCHEME P1

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1. P1:

1ai: What did governments tell industries?
To stop making products that used CFCs. [1]

1aii: What did governments tell consumers?
To stop using and dispose of products that used CFCs. [1]

1bi: How did they test about CFCs?
Carried out experiments many times/different locations etc. [1]

1bii: How did they increase confidence?
After stopping using CFCs they saw that the hole got no bigger. [1]

[Range of answers will be available for Q1]

Question 1 = [4 marks]

2a: 3000 - 1200 = 1800 [1]

[I think this was the value]

2b: 600 / 1000 = 0.6 [2] or 60% is % is labelled [2]

2c: Least energy is put into the slow cooker so will take longer to input the same amount of energy.
Diagrams showed that it had the highest output for input so highest efficiency (0.8) [3]

Question 2 = [6 marks]

3a: Calculated payback time for double glazing as 25 years, longest payback time of all of them. [2]

3b: Red and yellow shows hot areas so more energy lost. Blue shows cool areas so less energy lost. Shows what is well insulated and what isn't. [2] I believe the roof and windows were red and yellow and the walls were blue.

3c: Conduction and convection explanations in terms of the question.

Kinetic energy increases inside and the particles vibrate. This energy is then passed on through these vibrations. Particles become trapped. Convection current starts: kinetic energy raises where they expand and become less dense and rise and pass through to outside. [6]

Question 3 = [10 marks]

4a: Convection current in liquid.

Change in density so rise and replaced by denser particles forming a current. [2]

4bi: Temperature change.

Water - 60°
Cup - 40°C [2]

4bii: Why will the water have a higher change?

Because microwaves are absorbed by water particles and not plastic particles. [1]

Question 4 = [5 marks]

P1 = [25 marks]

P2:

5a: Write down two advantages of photocells.

Renewable energy.
No need for fuel.
No pollution.
Little maintenance.
Long life.

2 needed for [1]

5b: How do photocells work?

Light energy causes electrons to be 'knocked loose' from the silicon atoms in the crystal so electrons flow freely. [DC] [2]

5c: How does surface area increase output?

Increased surface area means more electricity produced and light can be collected from different places and at different angles. [2]

[Again a range of answers for 5c]

Question 5 = [5 marks]

6a: What causes these gases?

Water vapour: Evaporation
Carbon dioxide: Respiration
Methane: Decomposing material [3] [1 mark for each]

6b: How does the Earth treat infrared?

Infrared is absorbed by greenhouse gases. [1]

6c: Anita and her evidence.

Global warming effects the globe. Cold winters could contribute. [2]

6d: Natural phenomena.

Idea of factories warming the earth.
Volcanic ash reflects radiation into space. [1]

Question 6 = [7 marks]

7a: Which has the highest current?

Oven with current of 7.83 [3]

[1 mark for identifying oven and 2 marks for calculation current of answer to that part]

7b: Paying for electricity.

Uses 1.5Kw for 20 hours so 30KwH x 18 = 540 pence [2]

7c: National grid and voltage.

Increasing the voltage reduces the current which means that the cables get less hot and therefore less energy is lost as heat. [2]

Question 7 = [7 marks]

8: What type of radiation is coming from each source?

Source A - Gamma
Source B - Alpha
Source C - Beta
Source D - Gamma

Alpha stopped by few sheets of paper.
Beta stopped by few mm of aluminium.
Gamma stopped by few cm of lead.

A stays constant and drops at lead so Gamma.
B drops at paper and then stays constant so Alpha.
C stays constant then drops at aluminium so Beta.
D reduced slightly by paper and then drops fully at lead so Gamma.

[6]

Question 8 = [6 marks]

P2 = [25 marks]

P3:

9a: Tick boxes, different forces on cars.

Car

A - Increasing
B - Constant
C - Decreasing

[2]

9bi: Describe the speed acceleration graph.

As speed increases acceleration decreases. [1]

9bii: Forces on car causing acceleration to change.

Idea that as the car gets faster it reaches constant speed and therefore stops accelerating. [2]

Question 9 = [5 marks]

10a: Scientists collecting data about seat belts.

They could use dummies. Force using different seat belts measured and compared to show effectiveness. [2]

10b: How seat belts reduce injury in a crash.

Seat belts are designed to stretch, this reduces the acceleration and therefore the force.
Newton's second law of motion F = ma (acceleration reduction reduced force for same mass). [2]

10c: Safety features in cars.

Crumple zones.
Air bags.
ABS brakes. [1]

Any other safety feature really.

Two correct answers needed for 1 mark.

10di: Is Chloe correct?

NO!
This is because although thinking distance increases linearly:
Braking distance increases in a square rule.
Therefore stopping distance will not be double.
[Data from information can be used to justify this]. [2]

10dii: Factors that increase braking distance.

Increased mass.
Effectiveness of the brakes.
Braking force.
Friction between tyres and the road. [1]

Two correct answers needed for 1 mark.

Question 10 = [8 marks]

11: Speed and acceleration throughout the journey.

A shows acceleration.
B shows constant speed.
C shows deceleration.
D shows no movement.

Explain how the graph shows this.

You may use calculations to work out speed and acceleration and different points.

[6]

Question 11 = [6 marks]

12a: What is the acceleration?

2m/s^2 [1]

12b: What is the work done?

100 x 2800 = 280 000 J [3]

[2 marks if you forgot to divide distance by ½ and got 200 for distance]

12c: What is the power?

2800 x 20 = 56000 W [2]

Question 12 = [6 marks]

P3 = [25 marks]

Paper = [75 marks]

[These are approximate answers and not all might be correct]

This paper was easier than expected though still provided challenge. It covered some areas of the specification that were nice and some that weren't so nice. There were some things in there designed to trick people such as more information than you needed for some calculations (paying for electricity in particular). Therefore I would say that the grade boundaries will increase slightly, but not by too much. Good luck with P4P5P6!
2. I agree with all of these, it's what I got for all of them are you working on p2 and 3 as well?

Posted from TSR Mobile
3. for why will the water have a higher change?
i wrote that the oils Specfic heat capactity is less than the waters
4. (Original post by HouseOfRichman)
I agree with all of these, it's what I got for all of them are you working on p2 and 3 as well?

Posted from TSR Mobile
Yeah might need a bit of help with P3 though because I can't remember the answers to the back page calculations
Yeah might need a bit of help with P3 though because I can't remember the answers to the back page calculations
For the back page calculations i got 2m/s^2 for acceleration (20/10). 56000 J for part 2 and 560000 W for part 3.

I could be wrong though :/
6. (Original post by Irf00)
For the back page calculations i got 2m/s^2 for acceleration. 56000 J for part 2 and 560000 W for part 3.

I could be wrong though :/
I got these, however, for the work done someone corrected me and apparently it should be the following:
Work done = Force x Distance
Work done = 2800N x (0.5 x 10s x 20m/s) --- because to find the distance you need to find the area under the gradient
Work done should therefore equal 280 000J supposedly ??
Yeah might need a bit of help with P3 though because I can't remember the answers to the back page calculations
I got 2m/s^2, 280000J and 28000W
P1:

1ai: What did governments tell industries?
To stop making products that used CFCs. [1]

1aii: What did governments tell consumers?
To stop using and dispose of products that used CFCs. [1]

1bi: How did they test about CFCs?
Carried out experiments many times/different locations etc. [1] [I believe I wrote something along the lines of the scientists using satellites to monitor the levels of Ozone.]

1bii: How did they increase confidence?
After stopping using CFCs they saw that the hole got no bigger. [1] [Not too sure about this one, but I can't quite remember what I wrote.]

[Range of answers will be available for Q1]

2a: 3000 - 1200 = 1800 [1]

[I think this was the value]

2b: 600 / 1000 = 0.6 [2] or 60% is % is labelled [2]

2c: Least energy is put into the slow cooker so will take longer to input the same amount of energy.
Diagrams showed that it had the highest output for input so highest efficiency
(0.8) [3] [I worked out the energy efficiency for all of the appliances.]

3a: Calculated payback time for double glazing as 25 years, longest payback time of all of them. [2]

3b: Red and yellow shows hot areas so more energy lost. Blue shows cool areas so less energy lost. Shows what is well insulated and what isn't. [2] I believe the roof and windows were red and yellow and the walls were blue.

3c: Conduction and convection explanations in terms of the question.

Kinetic energy increases inside and the particles vibrate. This energy is then passed on through these vibrations. Particles become trapped. Convection current starts: kinetic energy raises where they expand and become less dense and rise and pass through to outside. [6] [Incredibly similar to the six mark question here: http://www.ocr.org.uk/Images/101014-...er-january.pdf]

4a: Convection current in liquid.

Change in density so rise and replaced by denser particles forming a current. [2]

4b: Temperature change.

Water - 60°
Cup - 40°C [2]

4c: Why will the water have a higher change?

Because microwaves are absorbed by water particles and not plastic particles. [1] [I'm not sure if this is right, but I wrote about something to do with the energy transfer being less with microwave radiation.]

[Total: 25]

[These are approximate answers and not all might be correct]
Hope this helps!
9. Hello, I have this paper with me and will post it on this thread once I have filled in the answers. If you wish, you can private message me if you're interested in some photos of the paper with the answers to use for this thread. Thanks, Callum
10. Here's a couple of the questions that I can remember from P2.

Photocells [first question]
Two advantages of photocells [2 marks]: They are robust and do not need to be replaced frequently, they do not have any long power cables, they do not produce pollution, they are not reliant on a fuel, etc.
How does a photocell work [2 marks?]
Why must the sign have a large area of photocells(?) [2 marks]
x
Hey, wasn't 1 (a) (ii) about humans? I wrote about the sun's exposure lol wtf.
12. (Original post by Chittesh14)
Hey, wasn't 1 (a) (ii) about humans? I wrote about the sun's exposure lol wtf.
Idk it could've been either but I interpreted it as CFCs and not UV.
Idk it could've been either but I interpreted it as CFCs and not UV.
No as in, I thought it said humans not consumers.
I wrote that they advised them to spend less time in the Sun because increased chance of skin cancer etc.
14. (Original post by Chittesh14)
No as in, I thought it said humans not consumers.
I wrote that they advised them to spend less time in the Sun because increased chance of skin cancer etc.
I get you, but I just interpreted the question as asking about the use of CFCs and not UV radiation.
6d: Natural phenomena.
Volcanic ash reflects radiation into space. [1]
Volcanoes cause a cooling effect, not global warming. The question was about global warming I think?
I get you, but I just interpreted the question as asking about the use of CFCs and not UV radiation.
Oh right, but did it say what governments advise humans?
17. (Original post by Chittesh14)
Oh right, but did it say what governments advise humans?
I can't really remember. But it is most likely both will be on the mark scheme.
I can't really remember. But it is most likely both will be on the mark scheme.
Okay
19. (Original post by CallumHawkitheus)
Hello, I have this paper with me and will post it on this thread once I have filled in the answers. If you wish, you can private message me if you're interested in some photos of the paper with the answers to use for this thread. Thanks, Callum
Thanks mate, much appreciated.

Could you post a picture of the first 6 maker mate.
20. What was the answer to that stupid acceleration and speed graph one?

What happens to the acceleration as the speed increases? The graph seriously was confusing, the acceleration decreased so I wrote it decreased as the speed increases.
But, in reality like science, the speed increases so the acceleration increases?

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