# Edexcel A-level Physics 1 (20th May) Unofficial MS [9PH0/01]

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#1
As in the title: post anything you remember from Monday's Edexcel physics paper.

I'll keep a summary of everything that's been covered on this Google sheet: feel free to suggest additions either here or there.

Some questions/question topics I remember are:
• Superconductors as a replacement for copper-based power grids.
• How much power is dissipated in a copper wire if 40MW are transmitted at 100kV over copper with a length of __ km and a resistivity of __ Ωm ? [Should have been 19kW so much more than the 7kW required by the cooling system. Use P=I^2 R because V^2/R would only work if this is the voltage across the wire, whereas it's actually the voltage across the supply - the components at the other end probably have a higher resistance and so have a higher potential across them.]

• Why do muons appear at sea-level despite having a lifetime of just 2.2μs? [6*]
• Talk about relativistic contraction/dilation due to v~=c: either A) the muon is travelling faster so its time is slower and, although it lasts a normal lifetime by its frame of reference, it lasts longer in ours. or B) the muon is travelling faster so the Earth appears contracted by its frame of reference - although it travels a normal distance in its frame of reference it travels further in ours.

• Flowers use electric fields to attract bees.
• What is the field strength at this point?
• Bees have hairs which can carry charge. How could they sense the electric field?
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#2
Which were 11 and 17?

(Original post by _gcx)
I am 99% sure this mark distribution is correct. Question order isn't correct bar q11 and q17:

• MCQs - 10
• Circular motion - 9
• Coins - 12 (6 + 4 + 2)
• Particle physics - 16 (3 + 3 + 2 + 2 + 6)
• Diode - 9 (2 + 2 + 2 + 3)
• Transformers - 9 (4 + 5)

• https://www.youtube.com/watch?v=EVCrmXW6-Pk - 10 (1 + 3 + 2 + 2 + 1 + 1)

• Hall voltage - 15 (3 + 1 + 4 + 3 + 2 + 2)
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3 years ago
#3
Final question
• Why electrons accumulate - FLHR means that there is an upwards force on the electrons causing them to move upwards and accumulate.
• Marking pd - top and bottom of the cuboid, some people put lines.
• Derivation of V = BI/(nte). Use either F = BIL = VQ/d or F = BQv = VQ/d then transport equation I = nave with a = dt
• Consistency of units - I used P/I with P = mgh/t to show that has units . Then use having units and having units
• Maximise (or minimise?) hall voltage - pick minimum (or maximum) value of . This was silicon either way.
• Angle - arctan(49/19) = 68.8 degrees?
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3 years ago
#4
(Original post by speedstyle)
Which were 11 and 17?

circular motion and hall voltage respectively
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3 years ago
#5
The length was 1.05km and resistivity was 2x10^-8 (measured from the graph)

(Original post by speedstyle)
• Superconductors as a replacement for copper-based power grids.
• How much power is dissipated in a copper wire if 40MW are transmitted at 100kV over copper with a length of __ km and a resistivity of __ Ωm ? [Should have been 19kW so much more than the 7kW required by the cooling system. Use P=I^2 R because V^2/R would only work if this is the voltage across the wire, whereas it's actually the voltage across the supply - the components at the other end probably have a higher resistance and so have a higher potential across them.]
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3 years ago
#6
I got 1.1x10^-8 from the graph
(Original post by AtomicCow)
The length was 1.05km and resistivity was 2x10^-8 (measured from the graph)
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#7
(Original post by Jr331)
I got 1.1x10^-8 from the graph
The scale was really weird (a log scale with nine divisions instead of ten) but it should have been around 2×10⁻⁸ Ωm as AtomicCow said. (When I saw how weird the scale was I measured it with a ruler and ended up with 2.1)

In general with log scales like that, each 'big' division is an exponent (so 10⁻⁹, 10⁻⁸, 10⁻⁷ etc.) and each 'little' division is a number within that exponent (so 1×10⁻⁸, 2×10⁻⁸, 3×10⁻⁸ etc.) so the little divisions get closer and closer together.
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3 years ago
#8
Hey Lemur14 would you be able to change the title of this thread for OP please? They would like it to say "Edexcel A Level Physics (9PH0) Unofficial Markschemes".
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#9
The reason for the name change is that I am adding today's paper 2 (and probably in a week or so paper 3) to the same spreadsheet. Again feel free to add anything you remember either here or as a suggestion on the sheet.
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3 years ago
#10
Off the top of my head:
• 14.9 for magnification
• 5.something * 10^-14 m^3 for volume
• 1356 for RMS speed
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3 years ago
#11
for the velocity displacement graph i got A because v=-wx so its a striaght line with a negative gradient. is this correct?
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3 years ago
#12
(Original post by CaptainCurry56)
for the velocity displacement graph i got A because v=-wx so its a striaght line with a negative gradient. is this correct?
No, not .
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3 years ago
#13
oh yeah, crap.
(Original post by _gcx)
No, not .
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3 years ago
#14
i remember that 18a was about why the plastic bag was suitable, 18bi was the activity of the sample and 18bii was the volume of helium produced.
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3 years ago
#15
15a was calculate the wavelength of the sound, 15b was define superposition and 15c was evaluate the student's statement about standing waves.
1
3 years ago
#16
17a was to find the magnification of the lens. 17bi was asking why only certain wavelengths appeared in the emission spectrum. 17bii was asking which slit separation was best. 17c was drawing the arrow to show the change in energy level.
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3 years ago
#17
MCQ
Binding energy per nucleon - increase | increase
SHM, velocity-displacement graph - n shaped curve (but a lot of people is getting circle)
H-R diagram - 3-5-1 (Main sequence-Red giant-white dwarf)
Polarising filter - 135
Stiffness constant - 1/2E
PE - Intensity affects rate of photoelectric emission
Luminosity - 4L
Upthrust - Vpg

I can't remember the last two
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3 years ago
#18
(Original post by sixsevennine)
MCQ
Binding energy per nucleon - increase | increase
SHM, velocity-displacement graph - n shaped curve (but a lot of people is getting circle)
H-R diagram - 3-5-1 (Main sequence-Red giant-white dwarf)
Polarising filter - 135
Stiffness constant - 1/2E
PE - Intensity affects rate of photoelectric emission
Luminosity - 4L
Upthrust - Vpg

I can't remember the last two
btw - there were two options . Iirc it was because was the density of the fluid?
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3 years ago
#19
(Original post by _gcx)
btw - there were two options . Iirc it was because was the density of the fluid?
Yeah sorry, I meant Vp(2)g because upthrust is the mass of FLUID displaced.
Do you remember the other 2 mcq? And did we get similar answers for mcq?
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3 years ago
#20
(Original post by sixsevennine)
Yeah sorry, I meant Vp(2)gbecause upthrust is the mass of FLUID displaced.
Do you remember the other 2 mcq? And did we get similar answers for mcq?
all the same answers but I think it was a full circle. I put 1/4 E in the exam but then I realised that the spring constant doubles too...

Other two were decay of radium into lead. I can't remember the answer but I think the option was C. And comparing electric and gravitational fields (I was prepared for a six marker on it, sad), the similarity was that potential was inversely proportional to separation. Remember they were all obviously wrong except A and D, but A is wrong because neutrally charged bodies don't feel a force in electric fields.
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