NSW INDEPENDENT TRIAL EXAMS – 2011
PHYSICS – YR 11 PRELIMINARY EXAMINATION
MARKING GUIDELINES
Section I
1
D
2
C
3
A
4
D
5
B
6
A
7
D
8
C
9
B
10
C
11
D
12
A
13
C
14
A
15
B
Section II
16(a)
Criteria
Provides correct answer
Sample answer: 8x10–8 m
Marks
1
16(b)
Criteria
Provides correct answer using wavelength above
Sample answer: 8x10–8 x 4.2x109 = 336 ms–1
Marks
1
17(a)
Criteria
Marks
Identifies each type of modulation
1
Sample answer: AM has the information encoded (superimposed) on the carrier wave by amplitude
modulation and FM has it encoded by frequency modulation.
17(b)
Criteria
Marks
Identifies the use of radio and microwaves and provides some frequency details
2
Identifies radio and microwaves
1
Sample answer: Radio waves between 500 kHz to 1600 MHz are used for broadcasting, while microwave
frequencies up to 30 GHz are used for mobile telephone communication.
18
Criteria
Marks
Provides a clear explanation outlining relevant physical principles
3–4
Provides some explanation of the physical principles involved
1–2
Sample answer: CD technology: CD’s are plastic disks, metal coated, then plastic coated again, used to store
digital data. Data is “burnt” onto the disk by a 780 nm laser beam which cuts a groove into the disk with
deeper, squarer pits, when the digital pulse is “1” rather than “0”. The sequence of pits encodes the data. The
data is read back when a similar laser is reflected from the pits and the light is read by a photo detector and
decoded by computer technology.
19(a)
Criteria
Marks
Calculates correct angle and shows angle on diagram
3
Provides calculation using incorrect refractive index and shows angle on diagram
2
Correct substitution only
1
Sample answer: For glass to air, n= 1/1.64 sin35° /sin r = 1/1.64
angle of refraction, r = 70°
70°
NSW Independent Trial Exams 2011– Physics Yr 11 Preliminary Exam: Marking Criteria - Page 1
19(b)
Criteria
Marks
Provides correct diagram for sending signals, diagram for receiving signals, identifies
4
focus and parallel rays and reason for large disc size
Provides THREE of the following: correct diagram for sending signals, diagram for
3
receiving signals, identifies focus and parallel rays and reason for large disc size
Provides TWO of the following: correct diagram for sending signals, diagram for
2
receiving signals, identifies focus and parallel rays and reason for large disc size
Provides EITHER correct diagram for sending signals OR diagram for receiving signals
1
OR reason for large disc size
Sample answer: Satellite dishes use large curved parabolic collectors – large so they can send a strong signal,
or receive a large amount of a weak signal from space, and curved so that the outgoing signal can be sent
from the focus to the dish surface and parallel beams reflected into space, or so that beams from space can
reflect from the curved surface and be collected at the focus.
Sending signals
Receiving signals
Parallel rays
Curved surface
Focus
20
Criteria
Marks
Names TWO sources of energy AND identifies TWO consequences for each
4
Names TWO sources of energy AND identifies ONE consequence for each
3
Names ONE source of energy AND identifies TWO or more consequences
2
Names ONE source of energy AND identifies ONE consequence OR names TWO
1
sources of energy
Sample answer: The advent of energy from coal rather than wood rapidly increased environmental pollution,
leading to the breathing problems associated with this, like asthma and bronchitis. Transport changed from
horses to steam trains which transported goods and people more rapidly. Electrical energy from coal fired
power stations also polluted the atmosphere but was safer and resulted in more production, more jobs, more
money and more affordable commodities for people.
21(a)
Criteria
Draws correct diagram with symbols for ammeter, voltmeter, globe, energy source
Draws circuit diagram with ONE of above incorrect or missing
Focus
Sample answer:
Marks
2
1
A
V
NSW Independent Trial Exams 2011– Physics Yr 11 Preliminary Exam: Marking Criteria - Page 2
21(b)
Criteria
Marks
Provides answer which identifies the source of the heating causing increased resistance
1
Sample answer: As current increases, the interaction of current electrons with particles in the resistor
increases and hence more electrical energy is converted into kinetic energy of motion of the lattice
particles. These particles then interact even more strongly with the current electrons. The temperature of
the conductor increases because of these heating effects.
22(a)
Criteria
Provides correct answer
Sample answer: Same current through points X, Y and Z
Marks
1
22(b)
Criteria
Marks
Provides correct answer for voltage AND current
2
Provides correct answer for voltage OR current
1
Sample answer: Same voltage across resistors B and C but current through C is half that through B
22(c)
Criteria
Marks
Provides correct comparison of potential difference and reason
2
Provides correct comparison OR identifies that resistance of B and C in parallel is less
1
than resistance of X
Sample answer: Potential difference across XY is greater than across YZ because resistance of B and C in
parallel is less than resistance of A and V = IR.
23
Criteria
Marks
Provides a comparison of the magnetic fields, the cause of each field and permanent
3
nature of magnet’s field
Provides TWO of the following: a comparison of the magnetic fields, the cause of each
2
field and permanent nature of magnet’s field
Provides ONE of the following: a comparison of the magnetic fields, the cause of each
1
field and permanent nature of magnet’s field
Sample answer: The magnetic field of a solenoid is generated by the electrons moving in the wire coils while
that of a bar magnet is continually present and results from the lined up magnetic dipoles of the spinning
electrons in the iron atoms. The fields are identical outside the magnet and solenoid with field lines coming
from one end and looping around towards the other end.
24
Criteria
Marks
Identifies a safety feature, describes its operation AND the application of a physics
3
principle
Identifies a safety feature and describes its operation OR the application of a physics
2
principle
Identifies a safety feature
1
Sample answer: Seat belts – during a front end collision, the inertia of the driver and passenger will cause
them to move forwards until the seat belt stops them (Newton’s first law). The belt will stretch a little, and
therefore the person will lose their momentum over a longer period of time than if they hit the hard
windscreen. The impact of the force applied to them by the belt will therefore be significantly less than if
they hit the windscreen (law of conservation of momentum). Seat belts will also prevent people being thrown
out of a vehicle.
NSW Independent Trial Exams 2011– Physics Yr 11 Preliminary Exam: Marking Criteria - Page 3
25(a)
Criteria
Marks
Identifies valid experiment AND reason
2
Identifies valid experiment
1
Sample answer: Given that validity judges whether or not the experiment is determining what you want it to determine, the first experiment is more valid as it determines the acceleration due to gravity. The second experiment may be in error value because the small effect of rolling friction between the ball and the incline has not been allowed for. The second experiment therefore may determine an acceleration less that the true value.
25(b)
Criteria
Marks
Identifies averaging of results AND eliminating outliers as reason
2
Identifies averaging of results as reason
1
Sample answer: The act of repeating an experiment allows you to judge whether or not your results are reliable (if they are all very close to each other). If outliers are detected and eliminated from the set of results, then the reliability of the result will be improved.
26
Criteria
Marks
Provides a correct assessment of EACH statement AND a statement of the correct
3
physics
Provides a correct assessment of ONE statement AND a statement of the correct physics
2
OR TWO correct assessments
Provides a correct assessment of ONE statement OR a statement of the correct physics
1
Sample answer:
Mike is totally wrong. The action is the force of the horse pulling the cart; the reaction will be the resistance
of the cart pulling backwards on the horse.
Susan is correct with the action but her reaction is incorrect. The reaction is the pull of the cart on the horse. Action and reaction pairs must always be forces (not movement) acting at the same point in opposite directions and between the same two objects.
27(a)
Criteria
Provides correct answer and units
Sample answer: Acceleration = gradient at 3 s = 0.5 ms–2 Marks
1
27(b)
Criteria
Calculates displacement and average velocity
Calculates average velocity using incorrect displacement
Sample answer: vave. = r / t = 16/10 =1.6 ms–1 Marks
2
1
27(c)
Criteria
Calculates work done correctly with correct units
Provides correct formulae but calculates incorrectly
Sample answer: Work done = KE gained = 1/2 mv2 = 4 J Marks
2
1
27(d)
Criteria
Calculates impulse correctly with correct units
Provides correct formulae but calculates incorrectly OR incorrect units
Sample answer: Impulse = change in momentum = 2x2 – 0 = 4Ns Marks
2
1
NSW Independent Trial Exams 2011– Physics Yr 11 Preliminary Exam: Marking Criteria - Page 4
28
Criteria
Marks
Provides a clear description of a model AND makes an assessment with justification
4
Provides a clear description of a model AND makes an assessment without justification
3
Identifies a model AND makes an assessment without justification
2
Identifies a model
1
Sample answer: Ptolemy stated that each planet moved on a small circle that moved on a larger circle with
the Earth off centre. The stars moved on a celestial sphere around the outside of the planetary spheres. The
complex geometry was able to explain the apparent retrograde motion of planets. His model accounted for
most of the observed motion of the planets and stars and therefore was useful for navigation purposes,
making it a good model.
29(a)
Criteria
Marks
Provides a correct statement of relationship
1
Sample answer: The brightness of a star is inversely proportional to the square of its distance from the
observer. 29(b)
Criteria
Provides diagram with axes labelled and main sequence and white dwarf areas labelled
Provides diagram with axes labelled or main sequence and white dwarf areas labelled
Sample answer:
Marks
2
1
Main sequence
Luminosity
White dwarfs
Temperature
29(c)
Criteria
Provides TWO characteristics
Sample answer: Strong magnetic activity and low temperature
Marks
1
30
Criteria
Marks
Provides a statement about each of the FOUR stages in correct order
4
Provides a statement about THREE of the four stages in correct order
3
Provides a statement about TWO of the four stages OR names four stages in order
2
Provides a statement about ONE of the four stages OR names four stages out of order
1
Sample answer: Theories suggest that the stages were:
1. Initially the Universe was exceedingly small and exceedingly hot and in an event called the Big Bang, it
exploded and expanding outwards, its temperature continually decreasing.
2. As it cooled, the particle motion decreased i.e. the KE decreased. By the time the Universe was just a few
minutes old, fundamental particles (quarks and electrons) existed and some combined to form protons
(hydrogen) and neutrons. Eventually helium nuclei were formed. After further cooling, hydrogen
molecules appeared.
3. Gravitational forces acted on the hydrogen and helium gas particles attracting them together so that some
areas had a greater density of gas than others. The matter in the Universe became “lumpy”.
4. Such clumping on a relatively small scale resulted in the birth of stars and clumping together under the
gravitational force caused stars to be concentrated into galaxies.
NSW Independent Trial Exams 2011– Physics Yr 11 Preliminary Exam: Marking Criteria - Page 5
NSW INDEPENDENT TRIAL EXAMS – 2011
PHYSICS – YR 11 PRELIMINARY EXAMINATION
MAPPING GRID
Question
Marks
Content
Outcomes (P)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16(a)
16(b)
17(a)
17(b)
18
19(a)
19(b)
20
21(a)
21(b)
22(a)
22(b)
22(c)
23
24
25(a)
25(b)
26
27(a)
27(b)
27(c)
27(d)
28
29(a)
29(b)
29(c)
30
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
4
3
4
4
2
1
1
2
2
3
3
2
2
3
1
2
2
2
4
1
2
1
4
8.2.1
8.2.3
8.2.1
8.2.4
8.3.4
8.3.2
8.3.2
8.3.3
8.4.2
8.4.2
8.4.1
8.4.4
8.5.3
8.5.2
8.5.2
8.2.2
8.2.1
8.2.3
8.2.3
8.2.5
8.2.4
8.2.4
8.3.1
8.3.2
8.3.2
8.3.2
8.3.2
8.3.2
8.3.5
8.4.4, 8.4.5
8.4.2
8.4.2
8.4.4
8.4.2
8.4.1
8.4.3
8.4.4
8.5.1
8.5.3
8.5.3
8.5.4
8.5.2
8
7
8,14
14
14
9, 12
9, 12
14
6
6, 14
14
6, 14
12
10
10
7
12
8
4, 8
4
12
5
1
13
14
14
14
14
9
4
2, 12
2, 12
14
12
12, 14
14
6, 14
1, 13
13
13
10
10, 13
Targeted
performance
bands
2-3
4-5
4-5
3-4
3-4
5-6
4-5
3-4
3-4
4-5
2-3
3-4
5-6
2-3
2-3
2-3
2-3
2-3
3-4
5-6
5-6
4-5
4-5
3-4
4-5
3-4
4-5
5-6
3-5
4-5
5-6
4-5
5-6
3-4
5-6
3-4
3-4
4-5
3-4
3-4
2-3
5-6
NSW Independent Trial Exams 2011– Physics Yr 11 Preliminary Exam: Marking Criteria - Page 6