PLACE
LABEL
HERE
Tasmanian Secondary Assessment Board
Tasmanian Certificate of Education
External Assessment
2001
PH866 PHYSICS
SECTION A
Time: 45 minutes
On the basis of your performance in this examination, the examiners will provide a rating of A, B,
C or D on each of the following criteria taken from the syllabus statement:
Criterion 2
Convey information in a variety of ways using established conventions
and appropriate language.
Criterion 7
Formulate generalisations and make realistic predictions based on
experimental data.
Pages:
Questions:
©
12
3
Copyright for part(s) of this examination may be held by individuals and/or organisations other than the Tasmanian
Secondary Assessment Board.
PH866 Physics
CANDIDATE INSTRUCTIONS
Answer ALL questions. Answers must be written in the spaces provided on the examination paper.
Recommended time:
Section A – 45 minutes
The PH866 Physics Formula Sheet can be used throughout the examination.
No other printed material is allowed into the examination.
The following will be taken into account when determining your assessment on Criterion 2:
•
•
•
numerical answers should have appropriate units and significant figures;
vectors should have magnitude and direction;
graphs should be in pencil and have appropriate scales, labelled axes, units, heading, clear
point placement and a suitable line of best fit;
•
diagrams should be used when appropriate (especially with vectors);
•
answers should be clearly and logically explained.
_______________________________________________________________________________
Question 1 (You should spend about 18 minutes in total on this question.)
The graphs opposite show how the distance travelled varies with time for two different cars A and
B travelling with slightly different initial speeds.
•
•
At time = 0, the drivers of the cars notice an obstacle on the road ahead.
After time = 1.5 seconds (which takes into account human reaction time) the drivers manage
to apply the brakes, so that the cars start to decelerate.
(a)
This question relates to the first 1.5 seconds of the motion for which both cars are travelling
at constant velocity.
(i)
Use the graph to determine total distance car B travelled in the first 1.5 seconds (ie
before the brakes first started to operate).
(2 minutes)
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(ii)
Car A was initially travelling at 16.0 ms-1, just under the current speed limit. Use the
graph to determine the initial speed of car B.
(4 minutes)
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Page 2
PH866 Physics
Distance travelled by two cars, A and B versus time after the drivers noticed the obstacle.
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Question 1 continues over the page.
Page 3
PH866 Physics
Question 1 (continued)
(b)
This question relates to the motion of the cars after the first 1.5 seconds when the cars are
decelerating.
(i)
If the obstacle was 43 m from the point at which the drivers first noticed the obstacle,
does car A hit the obstacle?
(1 minute)
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(ii)
Show that the speed of car B when it hit the obstacle was about 10 ms-1 – a speed which
can easily cause death in a collision.
(6 minutes)
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(iii) Comparing your answers to (i) and (ii), what can you conclude about the dangers of
travelling faster than the speed limit.
(5 minutes)
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Page 4
PH866 Physics
SPARE DIAGRAM
Distance travelled by two cars, A and B versus time after the drivers noticed the obstacle.
Page 5
PH866 Physics
Question 2 (You should spend about 20 minutes in total on this question.)
The data given below relates the distance a car travels before stopping while the brakes are applied
to its initial speed. The theoretical formula relating these quantities is:
s=
u2
2a
s = distance travelled before stopping (m)
u = initial speed (ms-1)
a = deceleration (ms-2)
s (m)
u (ms-1)
0.0
0
1.8
5
7.1
10
16.1
15
28.6
20
44.6
25
66
28
94
30
(a)
Modify the above data to enable you to plot a straight line graph relating s and u. Write your
modified data in the blank row of the table above.
(5 minutes)
(b)
Plot the straight line graph on the graph page opposite. (Some points may not fit a perfect
straight line.)
(5 minutes)
(c)
Use the graph to determine the value of the deceleration of the car for values of the initial
speed less than about 25 ms-1.
(6 minutes)
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(d)
For initial speeds greater than 25 ms -1 is the deceleration of the car more or less than the value
you obtained in part (c). Explain how you obtained your answer. (There is no need for any
calculation.)
(4 minutes)
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Question 2 continues opposite.
Page 6
PH866 Physics
Graph for Question 2(b)
Spare Graph for Question 2(b)
Page 7
PH866 Physics
Question 3 (You should spend about 7 minutes on this question.)
The graph opposite shows that the risk of having a casualty accident in a 60 km/h (about
16.7 ms -1) speed zone increases dramatically at speeds over 60 km/h. For example, cars travelling
at 85 km/h in a 60 km/h zone are about 57 times more likely to have a casualty accident than cars
travelling at 60 km/h.
How does the information presented in Questions 1 and 2 of this section help to explain the
dramatic increase in casualty rate?
(7 minutes)
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Page 8
PH866 Physics
Travelling Speed and the Risk of Involvement in a Casualty Crash Relative to Travelling at 60 km/h in a 60
km/h Speed Limit Zone.
60
50
40
Relative
risk of 30
casualty
20
10
0
35 40 45 50 55 60 65 70 75 80 85
Initial speed (km/h)
Data taken from Federal Office of Road Travel CR172 1997 Kloeden, C N et al
Page 9
PH866 Physics
BLANK PAGE
Page 10
PH866 Physics
BLANK PAGE
Page 11
PH866 Physics
FOR EXAMINERS USE ONLY
SECTION A
Question
Criterion 7
Criterion 2
1
2
3
Page 12
PLACE
LABEL
HERE
Tasmanian Secondary Assessment Board
Tasmanian Certificate of Education
External Assessment
2001
PH866 PHYSICS
SECTION B
Time: 75 minutes
On the basis of your performance in this examination, the examiners will provide a rating of A, B,
C or D on each of the following criteria taken from the syllabus statement:
Criterion 2
Convey information in a variety of ways using established conventions
and appropriate language.
Criterion 10
Incorporate techniques of analysis and mathematical manipulation
(algebraic, trigonometrical, numerical and graphical) to solve complex
problems.
Pages:
Questions:
©
12
5
Copyright for part(s) of this examination may be held by individuals and/or organisations other than the Tasmanian
Secondary Assessment Board.
PH866 Physics
CANDIDATE INSTRUCTIONS
Answer ALL questions. Answers must be written in the spaces provided on the examination paper.
Recommended time:
Section B – 75 minutes
The PH866 Physics Formula Sheet can be used throughout the examination.
No other printed material is allowed into the examination.
The following will be taken into account when determining your assessment on Criterion 2:
•
•
•
numerical answers should have appropriate units and significant figures;
vectors should have magnitude and direction;
graphs should be in pencil and have appropriate scales, labelled axes, units, heading, clear
point placement and a suitable line of best fit;
•
diagrams should be used when appropriate (especially with vectors);
•
answers should be clearly and logically explained.
_______________________________________________________________________________
Question 4 (You should spend about 15 minutes in total on this question.)
(a)
Two cars A and B approach each other at a right
angled corner and collide. After the collision they
remain together and initially travel as shown in the
diagram.
(i)
(ii)
Draw a vector triangle showing how
momentum is conserved during the collision.
(3 minutes)
Path after
collision
40 deg
A
B
If each car has mass 1000 kg and car B is known to have been travelling with speed
20 ms-1 before the collision, what was the speed of car A before the collision?
(4 minutes)
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Question 4 continues opposite.
Page 2
PH866 Physics
Question 4 (continued)
(b)
During the year 2001, the first space tourist spent a week on the new Space Station in orbit
around the earth.
(i)
What resultant force on the tourist (mass = 80 kg) would be required to give him an
upward acceleration of 25 ms-2?
(2 minutes)
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(ii)
While accelerating upwards, the tourist is supported by a padded chair. What force is
exerted by the chair on the tourist to give him the above upwards acceleration of
25 ms-2?
(3 minutes)
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(iii) The space station orbits the earth at a height above the earth’s surface of 400 km. If the
radius of the earth is 6378 km and its mass is 6.00 × 1024 kg, calculate the orbital period
of the space station about the earth.
(3 minutes)
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Page 3
PH866 Physics
Question 5 (You should spend about 15 minutes in total on this question.)
During periods in which the sun is particularly active (as it was in the year 2001), explosions on the
sun’s surface can result in high-energy protons and electrons leaving the sun and striking the earth
some time later.
(a)
(i)
If the protons have speed 6.0 × 107 ms-1 and the earth is 1.5 × 1011 m from the sun, how
long does it take for the protons to reach the earth?
(2 minutes)
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(ii)
What would be the radius of the circular path taken by these protons if they entered a
region in which the earth’s magnetic field had value 5.0 × 10-8 T, travelling
perpendicular to the field lines? Mass of proton = 1.67 10-27 kg
(3 minutes)
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(b)
The charged particles are deflected by the earth’s
magnetic field towards the earth’s poles where they
excite oxygen atoms (among others) in the upper
atmosphere. The oxygen atoms then emit red and
green light that can be seen in the sky as the
‘aurorae’.
The diagram opposite shows the relevant energy
levels within the oxygen atom and the electronic
transition responsible for the red light.
What is the wavelength of the red light?
6.77×10-19 J
3.59×10-19 J
Ground State
(4 minutes)
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Question 5 continues opposite.
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PH866 Physics
Question 5 (continued)
(c)
The ions bombarding the atmosphere can set up electric currents in the earth’s upper
atmosphere (the ‘ionosphere’).
Assume that the current is very thin as if flowing in a wire.
(i)
The current is 100 km above the earth’s suface and has value 5 × 10 6 A. At a point on
the earth’s surface directly beneath the current, what is the magnitude of the magnetic
field strength produced by this current?
(4 minutes)
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(ii)
If the current runs from south to north, what is the direction of the magnetic field in part
(i)?
(2 minutes)
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Page 5
PH866 Physics
Question 6 (You should spend about 15 minutes in total on this question.)
The following question illustrates some of the difficulties faced by architects in designing rooms
with good sound qualities. Take the speed of sound to be 320 ms-1.
(a)
Your examiner enjoys singing in the shower, which acts
as a closed organ pipe having length 2.4 m, width 1.0 m
and depth 1.0 m. The diagram opposite shows a side
view of the shower with a representation of one of the
standing sound waves that can be set up in the shower.
2.4 m
(i)
Show that the frequency of the sound wave
represented is 66.7 Hz.
(2 minutes)
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1.0 m
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(ii)
Give the frequency of the next harmonic produced by this 2.4 m long sound pipe.
(2 minutes)
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(iii) It is also noticed that there is a resonance at 160 Hz. Explain how this resonance comes
about. (Hint: Think of the horizontal direction.)
(3 minutes)
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Question 6 continues opposite.
Page 6
PH866 Physics
Question 6 (continued)
(b)
A
The diagram opposite shows two paths which
sound can take in travelling from an organ O
to a listener L in a theatre. The path OL is a
direct path of length 10 m while the path
OAL involves reflection of the sound off a
hard surface at A and has total length 15 m.
O
(i)
L
The organ plays a note of frequency 160 Hz. Show that the wavelength of the sound
produced is 2.0 m.
(2 minutes)
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(ii)
It is found that the sound of that note heard at L is quieter than at other parts of the
theatre. Explain this in terms of the interference between the two sound waves
travelling the two different paths.
(3 minutes)
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(iii) If the organ played a note of frequency 320 Hz would the sound heard by the listener at
L be louder or softer than at other parts of the theatre? Explain.
(3 minutes)
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Page 7
PH866 Physics
Question 7 (You should spend about 15 minutes in total on this question.)
(a)
An oil drop of mass 1.50 × 10 -16 kg is in the
space between two parallel metal plates
which are 1.00 cm apart. When a potential
difference of 46.0 V is applied to the plates
as shown, the drop remains suspended
without moving.
(i)
What is the gravitational force acting on the drop?
(1 minute)
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(ii)
Determine the charge on the drop.
(4 minutes)
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Question 7 continues opposite.
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PH866 Physics
Question 7 (continued)
(b)
In a cathode ray tube, electrons are fired from an electron gun and enter the space between
parallel plates, initially travelling parallel to the plates.
Electron
Gun
Electron beam
Parallel plates
(i)
If the electrons are accelerated through a potential difference of 1140 V in the electron
gun, show that their speed on leaving the gun is 2.00 × 107 ms-1.
(3 minutes)
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(ii)
If the plates have a length of 5.0 cm, what time does it take for the electrons to travel
horizontally the length of the plates?
(1 minute)
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(iii) In between the plates there is an electric field which imparts a sideways acceleration of
5.0 × 1015 ms-2 to the electrons. Show that the velocity component of the electrons
perpendicular to the plates when they leave the space between the plates is
1.25 × 107 ms-1.
(3 minutes)
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(iv) What is the direction of the electron velocity as the electrons leave the region between
the plates?
(3 minutes)
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Page 9
PH866 Physics
Question 8 (You should spend about 15 minutes in total on this question.)
(a)
A smoke detector uses the radioactive isotope americium–241. This emits alpha particles
ionizing the air around it and allowing an electric current to flow through the air. Smoke
prevents this current flowing.
(i)
Complete the following equation for the radioactive decay of americium–241 showing
all mass numbers and atomic numbers.
(2 minutes)
241
95Am
(ii)
→
Np
+
α
+
γ
α = alpha particle
γ = gamma ray
The activity of the americium in a smoke detector is about 35 kBq. If the half life of
americium–241 is 1.36 × 1010 seconds (432 yr), show that the number of atoms of
americium used in the smoke detectors is about 6.9 × 1014.
(4 minutes)
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(iii) Given the following isotopic masses, determine the energy released in the radioactive
decay of one atom of americium–241.
(4 minutes)
Americium–241
Neptunium–237
Helium–4
241.05862
237.04817
4.00260
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Question 8 continues opposite.
Page 10
PH866 Physics
Question 8 (continued)
(b)
The diagram shows a circuit set up to investigate the photoelectric effect. Photoelectrons
emitted from the photo detector travel to the collector to complete the circuit.
Variable Emf
power supply
Collector
Photo detector
Light beam
(i)
The photo detector is coated with caesium metal which has a work function of
3.09 × 10-19 J. If it is illuminated with light of wavelength 500 nm, show that the initial
kinetic energy of the emitted photoelectrons is 8.9 × 10-20 J.
(3 minutes)
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(ii)
If the photo detector is connected to the positive terminal of the power supply, what is
the largest emf (stopping potential) which will allow the photoelectrons to reach the
collector?
(2 minutes)
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Page 11
PH866 Physics
FOR EXAMINERS USE ONLY
SECTION B
Question
Criterion 10
Criterion 2
4
5
6
7
8
Page 12
PLACE
LABEL
HERE
Tasmanian Secondary Assessment Board
Tasmanian Certificate of Education
External Assessment
2001
PH866 PHYSICS
SECTION C
Time: 60 minutes
On the basis of your performance in this examination, the examiners will provide a rating of A, B,
C or D on each of the following criteria taken from the syllabus statement:
Criterion 2
Convey information in a variety of ways using established conventions
and appropriate language.
Criterion 9
Demonstrate and apply knowledge and understanding of terminology;
definitions and laws; concepts, theories and models; and uses of
measuring instruments of Physics.
Pages:
Questions:
©
16
3
Copyright for part(s) of this examination may be held by individuals and/or organisations other than the Tasmanian
Secondary Assessment Board.
PH866 Physics
CANDIDATE INSTRUCTIONS
Answer ALL questions. Answers must be written in the spaces provided on the examination paper.
Recommended time:
Section C – 60 minutes
NOTE:
Candidates have a choice in Question 10. Answer THREE of the four parts.
Candidates have a choice in Question 11. Answer parts (a) and (b) OR parts (c) and (d).
The PH866 Physics Formula Sheet can be used throughout the examination.
No other printed material is allowed into the examination.
The following will be taken into account when determining your assessment on Criterion 2:
•
numerical answers should have appropriate units and significant figures;
•
vectors should have magnitude and direction;
•
graphs should be in pencil and have appropriate scales, labelled axes, units, heading, clear
point placement and a suitable line of best fit;
•
diagrams should be used when appropriate (especially with vectors);
•
answers should be clearly and logically explained.
A set of spare diagrams has been provided in the back of the answer booklet for you to use if required.
If you use a spare diagram, please indicate you have done so in your answer to that question.
_______________________________________________________________________________
Question 9 (You should spend about 15 minutes in total on this question.)
(a)
The diagram shows a ray of light passing
between two different media, ‘Medium 1’
and ‘Medium 2’.
In which of the two media does light travel
with greater speed? Explain your reasoning.
(3 minutes)
Medium
Medium11
Medium22
Medium
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(b)
The diagram shows a ray of light undergoing
‘total internal reflection’ when it meets the
boundary of ‘Medium 3’ and ‘Medium 4’.
In which of the two media does light travel
with greater speed? Explain your reasoning.
(4 minutes)
Medium 3
Medium44
Medium
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Question 9 continues opposite.
Page 2
PH866 Physics
Question 9 (continued)
(c)
The diagram shows a series of wavefronts of
light approaching a narrow slit in a wall.
Complete the diagram showing the
wavefronts at the other side of the slit, and
explain how a person at point P will be able
to detect the light even though the wall
appears to block the light from reaching P.
(4 minutes)
P
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(d)
Radio waves can often travel around the surface of the earth by reflecting off the ionosphere
as shown in the diagram.
IONOSPHERE
A
EARTH
B
How might you explain the reflection of this radio wave? (Hint: consider your answer to
question (b) opposite.)
(4 minutes)
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PH866 Physics
Question 10 (You should spend about 30 minutes in total on this question.)
Answer THREE of the four parts to this question.
(a)
(i)
Using the principles of physics explain how the emission of high velocity exhaust gases
by a rocket engine causes the rocket to accelerate in the opposite direction. (5 minutes)
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(ii)
Older cars had very rigid bodies which tended to maintain their shape in a head on
crash. Newer cars are designed so that the front of the car ‘crumples’ in a crash. In
terms of the forces involved in a collision, explain why the newer cars are safer for their
occupants.
(5 minutes)
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Question 10 continues opposite.
Page 4
PH866 Physics
Question 10 (continued)
(b)
(i)
What is meant by Lenz’s Law which concerns the direction of a current induced in a
conductor by a changing magnetic field?
(2 minutes)
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(ii)
A bar magnet moves downwards into a
conducting coil as shown in the diagram
causing an induced current to flow in the coil.
S
On the diagram sketch:
N
•
•
•
The lines of magnetic force around the
bar magnet.
The lines of magnetic force produced by
the induced current in the coil.
The direction of the induced current in
the coil and external circuit.
G
Be sure to label clearly your additions to the
diagram.
(4 minutes)
(iii) What would happen to the direction and magnitude of the induced current as the bar
magnet fell through the coil and emerged from the bottom of the coil? Explain your
answer. A reasonable sketch graph of current against time will gain bonus marks.
(4 minutes)
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Question 10 continues over the page.
Page 5
PH866 Physics
Question 10 (continued)
(c)
A long elastic rope is fixed at one end. When a student holding the other end of the rope
vibrates the rope up and down the rope generally does not show any distinct pattern of
movement. However, at a certain frequency fo of vibration, the rope vibrates in the pattern
shown in the diagram:
(i)
Sketch the pattern that would be observed if the student vibrated the rope at twice the
frequency fo.
(2 minutes)
(ii)
Explain what is meant by the terms node and antinode as applied to the vibration in part
(i).
(4 minutes)
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(iii) During the year a new bridge in London was found to vibrate dangerously whenever a
large number of people walked across it. It was found that the people tended to walk in
step with each other at a frequency which corresponded to the frequency of vibration of
the bridge. Explain why the walking people should cause the bridge to build up such
large vibrations.
(4 minutes)
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Question 10 continues opposite.
Page 6
PH866 Physics
Question 10 (continued)
(d)
(i)
Briefly describe the production of X rays in a modern X-ray machine.
(5 minutes)
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(ii)
A beam of X-rays of wavelength λ0
strikes a piece of graphite. From the
other side of the graphite emerge Xrays having a new wavelength λ1 as
well as high velocity electrons. Draw
the
vector
triangle
showing
conservation of momentum in this
interaction, being sure to include the
two angles θ and φ shown on the
diagram.
(3 minutes)
(iii) Which is larger, λ0 or λ1 ? Explain.
λ1
θ
λo
φ
e-
(2 minutes)
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PH866 Physics
Question 11 (You should spend about 15 minutes in total on this question.)
Answer parts (a) and (b) OR parts (c) and (d) of this question.
(a)
(i)
A space tourist is within a rocket accelerating
upwards away from the earth. On the diagram
show the forces acting on the tourist. Using
the force diagram explain why the tourist has
an ‘apparent weight’ greater than his weight
on the surface of the earth.
(3 minutes)
..........................................................................
..........................................................................
Earth
(not to
scale)
..........................................................................
..........................................................................
............................................................................................................................................
(ii)
The space tourist is now within the
Space Station in orbit around the
Earth. Show the force(s) acting on
the tourist in this situation and explain
why
the
tourist
now
feels
‘weightless’.
(3 minutes)
............................................................
EARTH
............................................................
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Question 11 continues opposite.
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PH866 Physics
Question 11 (continued)
(iii) It has been proposed that a future
space station should be constructed as
a large rotating cylinder. A tourist
sits within this cylinder as shown.
Show the force(s) acting on the tourist
in this situation and explain why he
feels an apparent weight which is
greater than zero.
(Ignore any forces due to the earth.)
(3 minutes)
Direction
of rotation
............................................................
............................................................
............................................................
............................................................................................................................................
(b)
In an emergency, a car decelerates rapidly.
seat belt
(i)
A passenger who is wearing a seat
belt remains in contact with the seat
during the deceleration.
In the
diagram opposite show the horizontal
forces(s) acting on the person during
the deceleration.
(3 minutes)
(ii)
During the deceleration a passenger who is not wearing a seat belt moves forward
relative to the car and crashes into the front window of the car. In terms of Newton’s
laws explain why the passenger moves forward relative to the car.
(3 minutes)
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Question 11 continues over the page.
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PH866 Physics
Question 11 (continued)
OR
(c)
(i)
The diagram shows the magnetic field (dotted lines) around the earth (shaded). The
rectangle drawn inside the earth represents the bar magnet which would produce a
magnetic field equivalent to the earth’s magnetic field.
Label the diagram showing:
•
•
•
The north and south poles of the ‘bar magnet’.
The north and south magnetic poles of the earth.
Redraw the compass needle (shown) in the orientation it would take if it were
placed at point ‘A’ in the diagram, and it was free to rotate in any direction.
(4 minutes)
A
(ii)
S
N
Compass
What is meant by ‘angle of inclination’ (or ‘dip angle’). Illustrate your answer on the
diagram
(2 minutes)
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Question 11 continues opposite.
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PH866 Physics
Question 11 (continued)
Axis of rotation
(d)
(i)
The diagram shows a coil ABCD of
wire carrying a clockwise electric
current I in a magnetic field directed
to the right.
B
A
B
In the space below, give the direction
of the force acting on each side of the
coil:
(2 minutes)
D
AB
...................................................
BC
...................................................
CD
...................................................
DA
...................................................
C
I
Axis of rotation
(ii)
The diagram shows the same coil in a
magnetic field directed into the page.
On the diagram show the direction of
the forces acting on each side of the
coil.
(2 minutes)
B
I
(iii) If the coil is initially stationary, will the magnetic forces in part (ii) above cause it to
move?
(2 minutes)
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Question 11 continues over the page.
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PH866 Physics
Question 11 (continued)
(iv) A simple DC motor is constructed as shown in the diagram. A coil is free to rotate
(about the axis of rotation) in a magnetic field directed to the right in the diagram.
Label the diagram showing:
•
•
•
•
The commutator.
The brushes.
The position of the north and south poles of a magnet which would produce the
field shown.
The direction in which the coil will commence to rotate if it is initially
stationary.
(3 minutes)
Page 12
PH866 Physics
SPARE DIAGRAMS FOR SECTION C
Question 9 (c)
P
Question 10 (b)(ii)
S
N
G
Question 11 (a)(i)
Earth
(not to
scale)
Page 13
PH866 Physics
SPARE DIAGRAMS FOR SECTION C
Question 11 (a)(ii)
EARTH
Question 11 (a)(iii)
Direction
of rotation
Question 11 (b)(i)
seat belt
Page 14
PH866 Physics
SPARE DIAGRAMS FOR SECTION C
Question 11 (c)(i)
S
N
Compass
Question 11 (d)(ii)
Axis of rotation
B
I
Question 11 (d)(iv)
Page 15
PH866 Physics
FOR EXAMINERS USE ONLY
SECTION C
Question
Criterion 9
Criterion 2
9
10(a)
10(b)
10(c)
10(d)
11(a)(b)
11(c)(d)
Page 16