Download QAT Trial 2013

Centre Number
Student Number
2013 HSC TRIAL EXAMINATION
Physics
General Instructions
Total marks – 100
 Reading time – 5 minutes
Section I
 Working time – 3 hours
 Write using black or blue pen
 Draw diagrams using pencil
 Board-approved calculators may be used
 Use the multiple-choice answer sheet
provided on page 27
 Write your Centre Number and Student
Number at the top of this page, page 11
and the Multiple Choice Answer Sheet
Pages 3-19
75 marks
This section has two parts, Part A and Part B
Part A – 20 marks
 Attempt Questions 1-20
 Allow about 35 minutes for this part
Part B – 55 marks
 Attempt Questions 21-31
 Allow about 1 hour and 40 minutes for this
part
Section II
Pages 21-25
25 marks
 Attempt ONE question from Questions 32-34
 Allow about 45 minutes for this section
Disclaimer
Every effort has been made to prepare this Examination in accordance with the Board of Studies documents. No guarantee or warranty is made or
implied that the Examination paper mirrors in every respect the actual HSC Examination question paper in this course. This paper does not constitute
‘advice’ nor can it be construed as an authoritative interpretation of Board of Studies intentions. No liability for any reliance, use or purpose related to
this paper is taken. Advice on HSC examination issues is only to be obtained from the NSW Board of Studies. The publisher does not accept any
responsibility for accuracy of papers which have been modified.
TRPHY13B_EXAM
Page 1
BLANK PAGE
TRPHY13B_EXAM
Page 2
2013 HSC TRIAL EXAMINATION
PHYSICS
Part A – 20 marks
Attempt Questions 1-20
Allow about 35 minutes for this part
Use the multiple-choice answer sheet provided for Questions 1-20
Select the alternative A, B, C or D that best answers the question. Fill in the response oval
completely.
Sample
2 + 4 = (A) 2
(B) 6
(C) 8
(D) 9
A
B
C
D
If you think you have made a mistake, put a cross through the incorrect answer and fill in the
new answer.
A
B
C
D
If you have changed your mind and have crossed out what you consider to be the correct
answer, then indicate this by writing the word correct and drawing an arrow as follows:
correct
A
B
C
D
1
Following an arduous trip to the Moon, astronaut Aung San decides to relax throwing
darts at the dartboard on the wall of the settlement’s rest and recreation room. Taking
aim at the bullseye exactly 3.0 m away, she throws the first dart horizontally.
Relative to the time the dart would have taken had it been thrown when the craft was at
rest on the launching-pad on Earth, which of the following best describes the time it
takes on its current flight?
(A)
It takes less time
(B)
It takes more time
(C)
It takes the same amount of time
(D)
The time taken depends on the Moon’s gravitational acceleration.
TRPHY13B_EXAM
Page 3
The mass of the planet Neptune is 1.025  1026 kg. Its equatorial
radius is 24 766 km.
An astronaut with a mass of 80 kg is in a satellite moving in a
circular orbit directly over Neptune’s equator with a radius that
makes the acceleration due to gravity there exactly 9.8 m s-2.
Which of the given answers most correctly shows the orbital
radius of the satellite and the gravitational force on the astronaut?
2
(A)
rorb = 26 413 km; Fw = 0 N
(B)
rorb = 24 766 km; Fw = 891 N
(C)
rorb = 26 413 km; Fw = 784 N
(D)
rorb = 6.9765  108 km; Fw = 784 N.
3
Source - NASA – Image of the Day
gaery
Source - Wikipedia
On 4th October, 1957, the former USSR launched the first artificial satellite, Sputnik 1,
into a low-Earth orbit. Syncom-2, launched on 26th July, 1963, was the first satellite to
be placed in a circular geostationary orbit around the Earth.
Which of the following best describes the orbit of Syncom-2 compared with the orbit of
Sputnik 1?
(A)
Greater altitude, lower speed, longer period, lower gravitational acceleration
(B)
Greater altitude, greater speed, longer period, lower gravitational acceleration
(C)
Greater altitude, lower speed, shorter period, greater gravitational acceleration
(D)
Greater altitude, greater speed, shorter period, lower gravitational acceleration.
TRPHY13B_EXAM
Page 4
4
A rocket carrying a data-logger in its nose-cone is launched from the
ground, as shown in the diagram. The mass of the data-logger is 2.0 kg,
and the combined mass of the launch vehicle is 100 kg.
The thrust force applied by the rocket engine is 1540 newtons.
Which of the following alternatives most correctly identifies the initial
acceleration of the rocket, and the initial normal reaction force that is
measured by the data-logger, which rests on the floor of the nose cone?
http://www.photographyblogger.net/20-awesomerocket-launch-pictures-by-steve-jurvetson/
(A)
The initial acceleration is 5.6 m s-2 ↑; the initial data-logger reading is 19.6 N
(B)
The initial acceleration is 5.6 m s-2 ↑; the initial data-logger reading is 30.8 N
(C)
The initial acceleration is 15.4 m s-2 ↑; the initial data-logger reading is 19.6 N
(D)
The initial acceleration is 15.4 m s-2 ↑; the initial data-logger reading is 1540 N.
5
0.8 c
Consumed by his implacable hatred for Earthlings the Zaxxon
Warlord launched a solid metal sphere at 0.8 c directly at our
planet. It missed. However, a photograph was taken by one of
Earth’s space cameras as evidence for the Intergalactic Court.
Which of the following diagrams would most closely resemble the photographic image?
(A)
6
(B)
(C)
(D)
The planet Mars has two satellites, Phobos and Deimos. The orbit of Deimos, the small
outer satellite, is almost perfectly circular, having a radius of 23 458 km, and an orbital
period of 1.0908  105 s. From this data, which of the following answers most closely
identifies the orbital speed of Deimos and the mass of the planet Mars?
Orbital speed of Deimos
Mass of Mars
(A)
1.351 m s-1
1.09  1012 kg
(B)
1.351 m s-1
6.42  1014 kg
(C)
1.351  103 m s-1
6.42  1023 kg
(D)
1.351  103 m s-1
9.63  1024 kg
TRPHY13B_EXAM
Page 5
7
The half-life of a certain radioactive isotope is known to be 1 second when measured in
a laboratory on Earth. Nevertheless, when a stream of these isotopes is accelerated to a
very high speed, and then sent a distance of 6.0  108 m across space, the number of
particles arriving at a particle detector reveals that their actual half-life is 2 seconds. If
external influences and effects can be ignored, which of the following would be their
speed?
(A) 0.92 c
(B) 0.87 c
(C) 0.75 c
(D) 0.50 c
This diagram shows a rough 2-dimensional
representation of a 3-dimensional field.
Which of the following alternatives best
identifies which type of field it could be?
8
(A)
An electric field around two objects carrying equal like charges
(B)
A magnetic field around two like magnetic poles of equal strength
(C)
A gravitational field around two objects in space with identical masses
(D)
The field shown here would correctly represent two of these alternatives.
For Questions 9 and 10 consider the diagram below.
9
REGION 1
4.0 A
3.2  10-2 m
REGION 2
REGION 3
6.0 A
Two straight parallel wires 2.0 metres long and 3.2  10-2 m apart carry currents in the
directions shown. The wire on the northern side carries 4.0 A due west; that on the
southern side carries 6.0 A due east.
What is the strength and direction of the force acting on the wire on the southern side?
(A)
750 N due north
(B)
1500 N due south
(C)
1.5  10-4 N due north
(D)
3.0  10-4 N due south.
TRPHY13B_EXAM
Page 6
10
Consider once again the parallel wires shown in the diagram of Question 9.
Not only is there a force applied between the wires, there is a combined magnetic field
within the three regions identified in the diagram.
In which region are there points where this combined magnetic field is zero?
(A)
In Region 1
(B)
In Region 2
(C)
In Region 3
(D)
In both Region 1 and Region 3.
11
N
S
I
When electric current passes through the solenoid, a magnetic pole is created on its
right-hand end, and this interacts with the field of the horseshoe magnet.
Which pole is created, and what effect does it have on the solenoid?
12
(A)
A north pole is created at that end; the solenoid is forced to the left
(B)
A south pole is created at that end; the solenoid is forced to the left
(C)
A north pole is created at that end; the solenoid is forced to the right
(D)
A south pole is created at that end; the solenoid is forced to the right.


 P


.
f 

.



g



 I



 Q
.


The diagram shows a thin coil having only 10 loops, which is
free to rotate around the axis fg.
When direct electric current is passed through the coil when it
is located within the uniform magnetic field as shown, what is
the coil most likely to do?
(A)
The coil would remain stationary
(B)
The coil would rotate around fg so point P comes out of the page
(C)
The coil would rotate around fg so point Q comes out of the page
(D)
The coil would rotate through 180º in either of these two directions.
TRPHY13B_EXAM
Page 7
The device shown in this diagram is called an Aragó disc.
The actual disc is a circular plate made of aluminium or
copper, which can rotate freely on a crank handle. There
is a long horseshoe magnet attached to the crank handle,
so when it is turned the poles of the magnet move across
the surface of the plate, which is observed to rotate in the
same direction as the magnet is moving.
Why does the copper or aluminium disc turn while the
magnet continues to rotate as the handle is turned?
13
(A)
(B)
(C)
(D)
14
The metal of the disc is attracted by the moving magnet
Since the crank handle cannot be frictionless, the disc turns by the friction
The changing field induces an emf that opposes the motion of the magnets
The magnet’s poles attract or repel electrons as they move across the metal.
The Aragó disk is an excellent example of a significant principle of Physics.
Which of the following concepts does it portray?
15
(A)
Ohm’s law
(B)
The motor effect
(C)
The law of conservation of energy
(D)
The principle of the AC induction motor.
Paddle wheel
–
+
Glass “rails”
The “paddle wheel” tube originally made by Sir William Crookes demonstrated a
number of the various properties of cathode-rays.
Which of the following properties did this particular tube uniquely display?
(A)
Cathode-rays are emitted from the cathode
(B)
Cathode-rays are electrically charged particles
(C)
Cathode-rays possess momentum and kinetic energy.
(D)
Cathode-rays cause fluorescence when they strike certain materials.
TRPHY13B_EXAM
Page 8
Consider this uniform electric field, one essential part of the
Thomson experiment being carried out in a school laboratory.
16
Which of the following pairs of parallel plates is able to establish
the particular field displayed?
(A)
(B)
+ 25 V
(C) – 50 V
+ 150
V
(D)
More than one
of these could
 25 V
17
+ 200
V


..
.. ..





(A)
horizontal sweep
fluorescent screen
vertical sweep
electron-gun
(B)
vertical sweep
fluorescent screen
horizontal sweep
electron-gun
(C)
horizontal sweep
fluorescent screen
electron-gun
vertical sweep
(D)
electron-gun
horizontal sweep
fluorescent screen
vertical sweep
Maximum K.E. [eV]
18
set up this field.
This diagram shows the fundamental components
of an oscilloscope. Arrows point to these various
components, numbered from  to .
Which of the following answers correctly identifies
what the numbers refer to?
.

0V
The line on the graph indicates the relationship
between the frequency of the light illuminating
the surface of a particular metal and the
maximum kinetic energy of the photoelectrons
emitted from its surface, as measured by the
stopping voltage of those photoelectrons.
4
3
2
1
0
5
10
15
20
frequency [ 1014 Hz]
25
30
Which of the alternatives most correctly
identifies the work function of the metal (eV)
and its threshold frequency (Hz)?
(A)
Its work function is 0 eV; its threshold frequency is 8  1014 Hz
(B)
Its work function is 3.3 eV; its threshold frequency is 8  1014 Hz
(C)
Its work function is 2.5 eV; its threshold
frequency is 15  1014 Hz
.
(D)
Its work function is 3.5 eV; its threshold frequency is 17.5  1014 Hz.
TRPHY13B_EXAM
Page 9
ant
p
19
Although superconductivity was discovered in 1911, no plausible explanation of the
phenomenon was proposed until the BCS theory of John Bardeen, Leon Cooper and
Robert Schreiffer in 1957. In 1972 it won the Nobel Prize for Physics. Although it is
unable to explain the superconductivity of the ‘high temperature’ superconductors
nowadays commonly found in high school laboratories, it has not yet been replaced by
any alternative theory that can also explain the behaviour of these materials.
Apart from one, all the following are precepts of the BCS theory for a superconductor
at and below its critical temperature; which is the exception?
(A)
The electrical resistance drops sharply at its critical temperature, then decreases
uniformly to zero at Absolute Zero
(B)
All the electron pairs move at exactly the same speed as one another as they
pass through the crystal lattice of the material
(C)
Pairs of the material’s electrons ‘team up’ in a special electron-lattice-electron
interaction such that the first electron assists the passage of the second
(D)
p-type dopant
20
1
Forbidden gap
Acceptor level
The positive ions of the material’s crystal lattice are attracted inwards by the
first electron,
creating a positive
p-typeregion
dopantthat draws the second electron inwards.
p-type dopant
Conduction band
Conduction band
Conduction band
2
3
Forbidden gap Valence band
Forbidden gap
Valence band
Valence band
Forbidden gap
Forbidden gap
Forbidden gap
Acceptor level Other electron band
Acceptor level
Other electron band
Other electron band
Use this key to interpret these diagrams:
4
Conduction band
Valence band
Forbidden gap
Other electron band
Bands overlapping
Acceptor level
Donor level
The above Band Theory diagrams represent four different materials, an electrical
conductor, an insulator, a semiconductor doped with a p-type impurity and another
semiconductor, but doped with an n-type impurity.
Identify which of the four different materials is which.
(A)
1
Conductor
2
p-type S/C
3
Insulator
4
n-type S/C
(B)
Conductor
n-type S/C
Insulator
p-type S/C
(C)
Insulator
p-type S/C
Conductor
n-type S/C
(D)
Insulator
n-type S/C
Conductor
p-type S/C
TRPHY13B_EXAM
Page 10
2013 HSC TRIAL EXAMINATION
Centre Number
Student Number
Part B – 55 marks
Attempt Questions 21-31
Allow about 1 hour and 40 minutes for this part
Answer the questions in the spaces provided.
Show all relevant working in questions involving calculations.
Question 21 (5 marks)
Marks
The mass of the Moon is 7.35 × 1022 kg; its radius is 1737 km.
There are plans for Chinese astronauts to establish a permanent base
on the Moon in 2021, in order to mine its surface for minerals. It will
be necessary to bring air and food from Earth, whilst the ice found at
the bottom of many lunar craters will be used for water.
(a)
State what is meant by the term ‘escape velocity’.
1
(b) Find the escape velocity of an object projected from the Moon [show working].
2
(c)
2
Give reasons why projecting a 1000-kg object carrying lunar minerals from the
lunar surface to send it to Earth would be far more successful than projecting the
same mass from the surface of Earth for it to get to the Moon.
TRPHY13B_EXAM
Page 11
Question 22 (3 marks)
v m s-1
A frictionless glider is moving at a uniform
speed v m s-1 across a smooth horizontal
table 1.225 m high when it reaches the
edge, and falls to the floor and lands 1.8 m
away from the table.
1.225 m
Glider
Marks
1.80 m
(a) How long after leaving the table does it take to strike the floor?
2
(b) What is the speed v of the glider as it leaves the table?
1
Question 23 (4 marks)
(a) Describe one advantage of using multi-stage rockets to launch vehicles into space
and beyond.
2
(b) Identify which of the space pioneers Esnaut-Pelterie, Goddard, Oberth, O’Neill,
Tsiolkovski or Von Braun you investigated. Apart from multi-stage rockets, state
one of the concepts for which he was responsible, and describe its significance.
2
TRPHY13B_EXAM
Page 12
Question 24 (6 marks)
Marks
From Source
To detector
M1
SSM
M2
The Michelson-Morley experiment has been called
‘the most important null result in the history of
Physics’. This schematic diagram shows how light
from a source enters the device, is split, reflected,
split again, and after all that almost half of it is
transmitted to the detector.
(a) Using words or a labelled diagram, describe what is observed by the detector.
2
(b) Why did the scientists of that time believe that a ‘luminiferous aether’ had to
exist?
1
(c) Identify how the light pattern observed by the detector should have varied had the
aether in fact existed.
1
(d) The experiment carried out by Michelson and Morley was accurate, valid and
reliable but produced a null result. Other experiments in Physics have also been
known to produce null results.
Outline why this particular outcome was significant enough to warrant such a
description ‘the most important null result in the history of Physics’.
2
TRPHY13B_EXAM
Page 13
Question 25 (6 marks)
    
   A 
    
    
Liquid Na
    B  from reactor
    
Marks
A technique called magnetohydrodynamics, MHD, was
trialled as a means of producing electricity directly from
a nuclear reactor. Sodium, a metal that normally melts
at 97.7  C, is used as the coolant for the reactor core. It
is trapped inside pressurised pipes, and forced through
the reactor core. It heats up, turns to liquid, expands and
forces its way through a powerful magnetic field.
Potential difference is generated between the plates.
(a) Identify the Physics principle involved in MHD.
1
(b) In the diagram above, identify which of the plates A or B would become charged
negatively as the sodium flows in the direction marked. Justify your answer.
2
(c) Unfortunately, the efficiency of MHD for generating electricity in this way is far
too low to make it viable. However, applications of the principle described here,
where a metal is forced through a magnetic field to produce potential difference is
very common.
Use at least one labelled diagram to assist you to explain one example of an
efficient means of generating D.C. electricity.
3
TRPHY13B_EXAM
Page 14
Question 26 (6 marks)
Marks
Scale
Pointer
Spring
×
N
.
Current-carrying coil
S
Soft iron core
(a)
Identify two functions of the light coiled spring in this type of galvanometer.
2
(b)
Why is it necessary that the magnetic field is radial (using curved pole-pieces)?
1
(c)
What is the maximum angle through which the pointer can turn to allow a
reading to be taken? Justify your answer.
2
(d)
Consider a situation where a galvanometer such as this is designed to measure a
maximum current of 200 μA, which causes full-scale deflection. What would be
observed if the current were to be increased to 250 μA?
1
TRPHY13B_EXAM
Page 15
Question 27 (4 marks)

D

B1
B2






 p



A







Marks

C

q
Each side of the square coil ABCD is 10 cm long. It has 100
loops of wire. ABCD is free to rotate on the axis pq. Initially
it is perpendicular to a uniform magnetic field of 0.25 T. The
coil is contacted by two graphite brushes: B1 is in contact
with CD, and B2 is connected to AB.

B

The coil is now rotated through 90, AB coming upwards.
  the
 change

(a)  Determine
in magnetic flux passing through the coil during this
manoeuvre, showing working and providing the correct S.I. units.
2
(b) Indicating your reasoning, identify which brush becomes positive during this
manoeuvre?
1
(c) Which brush becomes positive if this is turned in the opposite direction instead?
1
Question 28 (2 marks)
The coil is connected to a 12-volt battery.
The switch is initially open. At t = 2.0 s it is closed, staying
closed until t = 5.0 s, when it is opened again. A graph of V
against t is shown below from t = 0 to t = 8.0 s. On the same
graph, neatly draw the graph of I against t showing the effect
of the back-emf induced in the circuit because of the coil.
2
P.D. [V]
12
8
.
4
0
0
TRPHY13B_EXAM
1
2
3
4
Time [s]
5
6
7
8
Page 16
Question 29 (5 marks)
Justify Hertz’ conclusion that the radio waves produced in his experiment actually
demonstrated the invisible electromagnetic waves predicted by Maxwell.
TRPHY13B_EXAM
Marks
5
Page 17
Question 30 (8 marks)
Marks
(a)
Using labelled diagrams in each case, describe fundamental differences
between a photoelectric cell and a photovoltaic (or ‘solar’) cell.
3
(b)
Photons of electromagnetic radiation having a wavelength of 5.6  10-7 m
strike the cathode of a photoelectric cell, the threshold frequency of which is
7.23  1014 Hz.
They are also used to illuminate a photovoltaic cell which has a band-gap
(energy) of 1.22 eV. Showing your working, determine the outcome of each
of these interactions.
4
(c)
Identify why photoelectric cells are an obsolete technology, meaning that
they are very seldom used in modern times, having been replaced by solar
cells.
1
TRPHY13B_EXAM
Page 18
Question 31 (6 marks)
Marks
Section 9.4.2, column-3, dot-point 5 of the HSC Physics syllabus requires students
to “process information to discuss Einstein and Planck’s differing views about
whether science research is removed from social and political forces”.
Contrasting their differing views on this issue, consider the following problem.
In order to obtain the financial support necessary to carry out research, scientists
have three principal sources – government grants, industry and the military.
Discuss the potential limitations to their freedom to publish their results posed by
each of these sources.
6
END OF CORE SECTION
TRPHY13B_EXAM
Page 19
2013 HSC TRIAL EXAMINATION
Physics
Section II
25 marks
Attempt ONE question from Questions 32-34
Allow about 45 minutes for this section
Answer the question in a SEPARATE writing booklet.
Show all relevant working in questions involving calculations.
Page
Question 32
Medical Physics
21-22
Question 33
Astrophysics
23-24
Question 34
Quanta to Quarks
TRPHY13B_EXAM
25
Page 20
Question 32 – Medical Physics (25 marks)
(a)
Marks
Describe how an endoscope functions.
2
(b)
0
1
2
3
4
Time (days)
This graph relates to a certain radioactive isotope that is to be used as a
diagnostic tool for a patient with a suspected cracked elbow that an X-ray has
been unable to reveal.
(i)
What would be an appropriate label for the vertical axis of the graph?
1
(ii)
What is the half-life of this isotope?
1
(iii)
If the initial dose received by the patient was 0.48 μg of the isotope,
what mass would remain in her system after 72 hours?
1
(iv)
Outline how γ-radiation is produced and used in positron emission
tomography (PET).
Identify a potential hazard in the use of this diagnostic tool.
3
(v)
(c)
Material
Air
Fat
Muscle
Density [kg m-3]
1.3
925
1075
1
Velocity of sound [m s-1]
330
1 450
1 590
This table provides information about the properties of some tissues.
(i)
Determine the acoustic impedance of muscle tissue.
1
(ii)
Ultrasound passing through body fat strikes a boundary of muscle
tissue. Explain what occurs with the waves at this boundary, and
I
determine the ratio r at this boundary.
I0
3
Question 32 continues on the next page
TRPHY13B_EXAM
Page 21
Question 32 – Medical Physics (continued)
(d)
Well over a century since its discovery X-ray imaging continues to be a major
technique for medical diagnosis. CAT scanning is a more recent enhancement
of the X-ray principle, exploiting the development of solid state computing
during the past 25 years.
Jmage 1
(e)
Marks
Jmage 2
(i)
Identify a key reason why CAT scanning has not completely replaced
conventional X-ray imaging in medical applications.
1
(ii)
Explain the physics behind the way X-rays can produce visual contrast
between distinct types of body tissues.
2
(iii)
The images above show the lungs. Image 1 is a CAT scan showing a
horizontal slice across the thorax. Image 2 is a conventional X-ray
image with the front of the body facing.
Account for the different appearance of the CAT image in terms of the
way in which data from X-ray photon scanning is processed in this
imaging technique.
3
Explain the use of the MRI imaging technique for obtaining scans, comparing
its effectiveness and assumed level of risk against that of CAT scans.
6
TRPHY13B_EXAM
Page 22
Question 33 – Astrophysics (25 marks)
(a)
(i)
1
2
Marks
3
2
4
These images represent a binary in the constellation Circinus. The
photographs were taken one year apart.
What type of binary is shown in this set of images?
State the reasoning for your answer.
(ii)
(b)
(c)
(d)
Explain the appearance of this type of binary.
2
Consider the following table, which contains data about several stars:
Star
Spectral class Absolute magnitude Apparent magnitude
Achernar
B5
– 2.70
0.46
Betelgeuse
M2
– 5.50
0.70
Canopus
F2
–5.60
– 0.72
Deneb
A2
– 7.09
1.25
Elnath
B7
– 1.37
1.65
(i)
Which of the stars in this table has the greatest luminosity?
1
(ii)
Which of the stars above is closest to Earth?
1
(iii)
Which of this group is the largest? Justify your answer.
2
(i)
Describe the properties of a globular cluster.
4
(ii)
Neatly sketch the H-R diagram of a typical globular cluster.
2
(iii)
Why would it be highly unlikely for a hot blue star to be found there?
1
Cepheid variables have played a significant role in our understanding of the
Universe. Describe what Cepheid variables are, and the particular properties
of these objects that have led astrophysicists to significant discoveries that
have changed the concept of what the Universe is.
6
Question 33 continues on the next page
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Question 33 – Astrophysics (continued)
(e)
Marks
Spectrum from the 2dF Quasar Survey
(i)
The diagram above shows the radiation spectrum typical of a quasar.
Compare this with the typical radiation spectrum of a distant galaxy.
2
(ii)
Compare it with the radiation spectrum of an emission nebula.
2
End of Question 33
TRPHY13B_EXAM
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Question 34 – Quanta to Quarks (25 marks)
(a)
(b)
Marks
(i)
The colour of one of the Balmer hydrogen spectral lines is blue. Using
this information alone, what must be its nf in the Rydberg formula?
1
(ii)
The wavelength of a different line in the Balmer series is 389 nm.
Showing your working, determine the ni of that specific spectral line.
2
A partial solution to the energy crisis facing Earth’s future generations – that
of an increasing population with their demand for energy, tempered by the
fragile atmosphere – may lie in the fusion of helium-3 nuclei. Helium-3 is
very rare on Earth, but there is believed to be a vast supply embedded in rocks
on the Moon. The effective fusion reaction is: 2 23 He  42 He  2 11 H
(i)
The masses of the relevant nuclei are:
H-1: 1.007825 amu; He-3: 3.016029 amu; He-4: 4.002603 amu.
Determine the energy released if 1.00 kg of helium-3 is fused.
(ii)
Plasmas used for fusion are so hot they can only be contained by using
“magnetic bottles”. Describe why the fusion of helium-3 would be
ideal for this form of energy production.
(c)
Explain how de Broglie’s postulate of matter-waves was confirmed
experimentally.
The mass of a proton is 1.673  10-27 kg. If the nucleus of a hydrogen
atom is considered as a cube with sides 1.0  10-15 m wide, with the
proton “trapped” inside it, acting as a de Broglie matter-wave, what
would be the speed of the proton in the simplest case, for which it is
considered to behave as a single standing-wave?
3
Comment on the significance of Heisenberg’s Uncertainty Principle,
h
written as x p 
, in this situation.
2
Consider the simplified model of an interaction between two hadrons below:
1
(ii)
2
(iii)
u u
d
(e)
1
In 1924 Louis de Broglie suggested that since it was now
accepted that electromagnetic radiation (waves) also possessed
particle-like properties, then particles might also possess
wave-like properties. He based his proposal upon what he
called ‘symmetry of nature’ rather than any theoretical or
experimental evidence.
(i)
(d)
3
+
u
d
=> ?
(i)
Identify the two distinct types of hadron depicted here.
2
(ii)
Identify the quarks present.
2
(iii)
What is the outcome of this interaction?
1
Assess the impact of the development of nuclear power stations for electricity
production throughout the world.
TRPHY13B_EXAM
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