external assessment 2020: physics question and response
TRANSCRIPT
Cle
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ter
com
plet
ion
of a
sses
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LUI School code
School name
Given name/s
Family name
Attach your barcode ID label here
Book of books used
PhysicsPaper 2
Time allowed• Perusal time — 10 minutes
• Working time — 90 minutes
General instructions• Answer all questions in this question and
response book.
• Write using black or blue pen.
• QCAA-approved calculator permitted.
• QCAA formula and data book provided.
• Planning paper will not be marked.
Section 1 (37 marks)• 9 short response questions
External assessment
Question and response book
Do not write outside this box.
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Section 1
Instructions• If you need more space for a response, use the additional pages at the back of this book.
– On the additional pages, write the question number you are responding to.
– Cancel any incorrect response by ruling a single diagonal line through your work.
– Write the page number of your alternative/additional response, i.e. See page …
– If you do not do this, your original response will be marked.
DO NOT WRITE ON THIS PAGE
THIS PAGE WILL NOT BE MARKED
Do not write outside this box.
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QUESTION 1 (1 mark)Explain why an object with mass cannot travel at the speed of light in a vacuum.
QUESTION 2 (6 marks)A physicist measured the electric field strength at different distances away from a point charge. The data is plotted in the graph.
Elec
tric
fi eld
stre
ngth
(N C
–1)
2500
2000
1500
1000
500
00 0.005 0.01 0.015
(m–2)0.02 0.025 0.03
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a) Identify the mathematical relationship between E and [3 marks]
b) Use the mathematical relationship identified in 2a) to deduce the magnitude of the charge creating the electric field. [3 marks]
Charge = C (to 1 decimal place)
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4 of 17
QUESTION 3 (5 marks)The diagram shows the atomic energy levels of the atoms in an unknown gas.
Ionisation
–5.6 eV
–1.3 eV
–2.7 eV
–4.1 eV
Predict the shortest wavelength of visible light that could be emitted from this unknown gas. (Note: The range of visible wavelengths of light is between 400 nm and 700 nm.)
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QUESTION 4 (5 marks)Describe how experiments on the photoelectric effect provide evidence of the quantised nature of photons.
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QUESTION 5 (4 marks)An electron is situated halfway between two nuclei that are separated from each other by a distance of 4.5 × 10-10 m. The first nucleus contains two protons. The second nucleus contains three protons.
Calculate the magnitude of the overall electromagnetic force experienced by the electron.
Force = N (to 1 decimal place)
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QUESTION 6 (4 marks)The diagram shows a particle, Q, entering a uniform magnetic field of 0.090 T. The particle has a speed of 1.5 × 10 m s-1. Once in the magnetic field, the particle moves in a circular path as shown.
Q
B = 0.090 T
r = 0.348 m
It is suspected that Q is one of the particles listed in the table.
Particle number Charge, q (C) Mass, m (kg)
1 – 1.60 × 10 9.11 × 10
2 + 1.60 × 10 9.11 × 10
3 + 1.60 × 10 1.67 × 10
4 + 1.60 × 10 3.34 × 10
5 – 1.60 × 10 3.34 × 10
Determine which particle Q is most likely to be.
Particle Q =
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QUESTION 7 (3 marks)A photoelectric effect experiment is conducted by shining different frequencies of light on a sample of aluminium. The kinetic energy of the ejected photoelectrons was measured. The data is plotted in the graph.
6
0
4
–2
2
–4
5
–1
3
–3
1
–5
–6Incident frequency (1014 Hz)
Kin
etic
ene
rgy
(10–1
9 J)
0 4 82 6 10 131 5 9 123 7 11 14
Identify the mathematical relationship between kinetic energy, E , and incident frequency, f.
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QUESTION 8 (4 marks)The diagram shows an object sliding down a frictionless inclined plane.
θi
Object
Not drawn to scale
The graph shows the velocity of the object measured at various times.
35
20
30
10
0
15
25
5
1 3 52 4 60
Velo
city
(m s–1
)
Time (s)
Determine the angle of incline, θ , of the inclined plane. Show your working.
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QUESTION 9 (5 marks)Nine planets orbit the same star. The orbital radius and orbital period of each planet was measured. The graph shows the cube of the orbital radius of each planet, r , compared to its orbital period squared, T .
18
12
16
8
4
0
10
14
6
2
10 000 30 000 50 00020 000 40 000 60 0000 70 000
Orb
ital r
adiu
s cub
ed, r
3 (10
32 m
3 )
Orbital period squared, T 2 (days2)
Determine the mass of the star. Show your working.
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ADDITIONAL PAGE FOR STUDENT RESPONSESWrite the question number you are responding to.
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15 of 17
ADDITIONAL PAGE FOR STUDENT RESPONSESWrite the question number you are responding to.
Do not write outside this box.
16 of 17
ADDITIONAL PAGE FOR STUDENT RESPONSESWrite the question number you are responding to.
Do not write outside this box.
17 of 17
ADDITIONAL PAGE FOR STUDENT RESPONSESWrite the question number you are responding to.
Clear zone —
margin trim
med off after com
pletion of assessment
© State of Queensland (QCAA) 2020Licence: https://creativecommons.org/licenses/by/4.0 | Copyright notice: www.qcaa.qld.edu.au/copyright — lists the full terms and conditions, which specify certain exceptions to the licence. | Attribution: © State of Queensland (QCAA) 2020