For all Queensland schools

2017 Senior External Examination

Physics Thursday 2 November 2017Paper One — Question book 9 am to 11:40 am

Time allowed• Perusal time: 10 minutes• Working time: 2 hours 30 minutes

Examination materials provided• Paper One — Question book• Paper One — Resource book• Paper One Part A — Multiple-choice response sheet• Paper One — Response book

Equipment allowed• QCAA-approved equipment• ruler graduated in millimetres• non-programmable calculator• graphing calculator

DirectionsYou may write in this book during perusal time.Paper One has two parts:

• Part A — Knowledge of subject matter:Section 1 — Multiple choiceSection 2 — Short response

• Part B — Scientific processesAttempt all questions.

Suggested time allocation• Part A: 1 hour 30 minutes• Part B: 1 hour

AssessmentPaper One assesses the following assessment criteria:

• Knowledge of subject matter• Scientific processes

Assessment standards are at the end of this book.

After the examination sessionTake this book when you leave.

Planning space

1

Part A — Knowledge of subject matterPart A assesses knowledge of subject matter and its simple application based on the topics in the Physics Senior External Syllabus 2000 (amended 2003).

Part A is worth 40 marks.

Suggested time allocation: 1 hour 30 minutes.

Section 1 — Multiple choice

Section 1 has 15 questions, each worth one mark. Attempt all questions.

Each question contains four options. Select the option that you think is correct or is the best option. Respond on the multiple-choice response sheet.

Question 1

The equation used to determine displacement is

12s = ut + at2

where in this case

initial velocity (u ) = 3.75 ms–1 acceleration (a ) = 0.3 ms–2

time (t ) = 5.0 × 102 s

How many significant figures should be present in the answer?

A one

B two

C three

D four

2

Question 2

The graph below shows the change in displacement over time for an object.

16

12

8

4

02.00.0 4.0 6.0 8.0 10.0

Time (s)

Displacement vs Time

Dis

plac

emen

t (m

)

According to the graph, the object first experienced a force at time

A 0.0 s.

B 4.0 s.

C 6.0 s.

D 8.0 s.

Question 3

A person travels 40 m in a straight line in 15 s, rests for 15 s and then travels 50 m in the same direction in 15 s. Their average velocity is

A 0.4 ms–1.

B 0.5 ms–1.

C 2.0 ms–1.

D 2.5 ms–1.

Question 4

The acceleration due to gravity on the Earth’s surface is represented by g . If a planet had a mass that was four times the mass of the Earth, how many times larger must the planet’s radius be than Earth’s to experience the same acceleration due to gravity, g , on its surface?

A 0.25

B 0.5

C 1.5

D 2.0

3

Question 5

An object thrown upwards at an angle to the horizontal in a gravitational field such as near the Earth’s surface will describe a parabola. Neglecting air resistance, the overall shape of the parabola is not a function of

A the mass of the Earth.

B the inital speed of the projectile.

C the mass of the projectile.

D the angle at which it is thrown.

Question 6

The momentum of an object is a product of its mass and its velocity. Impulse is a term that expresses the change in momentum. The unit of Impulse (I ) could therefore be expressed as

A kg.m.s

B kg.m.s–1

C kg.m.s–2

D kg.m.s–3

Question 7

Along a transverse wave, there is a net transfer of

A mass.

B energy.

C both mass and energy.

D neither mass nor energy.

4

Question 8

Four different devices are set up and the current flowing through them and the potential difference across them was recorded and displayed on the following graphs.

100v

50

50I (mA)

Device A

100

100v

50

50I (mA)

Device B

100

100v

50

50I (mA)

Device C

100

100v

50

50I (mA)

Device D

100

Which one of the devices is an Ohmic conductor?

A Device A

B Device B

C Device C

D Device D

Question 9

The value of the critical angle at which total internal reflection occurs at the boundary between media when light moves from a less optically dense medium to an optically denser medium is best given by

A the minimum possible angle of incident light.

B the maximum possible angle of incident light.

C the minimum possible angle of totally reflected light.

D the maximum possible angle of totally reflected light.

Question 10

The higher the power rating of an appliance the

A higher the resistance of the appliance.

B lower the cost of running the appliance.

C higher the rate of energy use by the appliance.

D lower the voltage applied to and current through the appliance.

5

Question 11

Consider the parallel charged plates represented below and the points between the plates as indicated by the letters.

A

D

G

B

E

H

C

F

I‒

+

Which statement below regarding the plates is false?

A A positive charge placed at point A experiences a stronger force from the positive plate than from the negative plate.

B A positive or negative charge placed at point D will experience zero net force.

C All of the points represent areas of equal field strength.

D Work is done by the field in moving a positive charge from C to I.

Question 12

A magnetic field exists around a current carrying wire as indicated in the diagram below. At point P the field strength is 2.0 × 10–5 T.

A

C

B

D

P

If the current through the wire is halved, then

A the field strength at A is 1.0 × 10–5 T out of the paper.

B the field strength at B is 2.0 × 10–5 T out of the paper.

C the field strength at C is 1.0 × 10–5 T into the paper.

D the field strength at D is 2.0 × 10–5 T into the paper.

6

Question 13

A full wave rectifier would not usually contain

A a PNP transistor.

B a PN diode.

C a capacitor.

D output terminals.

Question 14

The element represented by 2351X is

A vanadium.

B antimony.

C nickel.

D tungsten.

Question 15

A bone is unearthed by a scientist and is found to contain 25% of the carbon-14 present when it was a part of a living organism. Given the half-life of carbon-14 is 5 730 years, the bone is most likely

A 2 865 years old.

B 5 730 years old.

C 11 460 years old.

D 17 190 years old.

End of Section 1

7

Section 2 — Short response

Section 2 has 10 questions, worth a total of 25 marks. Attempt all questions.

Write your responses in the response book. Show all working.

Question 1

List the number of significant figures in each of these examples.

a. 5.02

b. 0.27 × 10–2

(1 mark)

Question 2

Convert the percentage error into an absolute error.

52.5 ± 2 %

(1 mark)

Question 3

A 100 kg object travelling at 30 ms–1 experiences an opposing force of 50 N for 30 s. Calculate the final velocity of the object.

(3 marks)

Question 4

A person pushes a 600 kg car along after running out of petrol. The car moves with a uniform velocity of 1 ms–1, and the person pushing must overcome a frictional force of 50 N.

a. How much work is done in pushing the car to a garage 100 m down the road and at an elevation 2 m higher than when the pushing began?

b. Calculate the power involved.

(4 marks)

8

Question 5

Respond to this question on page 25 of your response book. Two in-phase point sources, A and B, generate waves as indicated in the diagram below, in which the full lines indicate crests and the dotted lines indicate troughs. Comment on the difference in path length between the lines AP and BP with reference to the wavelength of the waves and the type of interference produced at point P.

P

A B

(2 marks)

Question 6

In a Young’s double-slit experiment light was passed through two slits 0.325 mm apart and a pattern of bright and dark fringes appeared on a screen 7.20 m away. The distance between pairs of adjacent bright fringes was found to be a constant 1.43 cm. From this data determine the wavelength of the light used in the experiment.

(3 marks)

Question 7

What power is required to move a charge of 2.0 × 10–14 C across a potential difference of 2.5 × 102 V in 2 s?

(2 marks)

9

Question 8

A label from a television is shown below.

What is the internal resistance of the television?

(3 marks)

Question 9

An electron having a charge of 1.6 × 10–19 C and a mass of 9.1 × 10–31 kg enters a magnetic field of 6.5 × 10–5 T at an angle of 30 degrees to the field lines with a velocity of 5.0 × 105 ms–1. Calculate the magnetic field of the force and the magnitude of the acceleration experienced by the electron as a result of interacting with the field.

(4 marks)

Question 10

Deep space probes such as Voyager, are powered by 'thermionic' devices which convert the heat from radioactive decay directly into electrical energy. The typical radioisotope used is Pu238 which decays to U234.

Write a balanced nuclear equation for this reaction and hence determine the type of decay occurring.(2 marks)

End of Section 2

End of Part A

10

Part B — Scientific processesPart B assesses scientific processes based on the topics in the Physics Senior External Syllabus 2000 (amended 2003) and practical work undertaken during your study of the subject.

Part B has six questions, worth a total of 25 marks. Attempt all questions.

Write your responses in the response book. Show all working.

Suggested time allocation: 1 hour.

Question 1

The diagram below shows maximum velocity vs mass for a number of animals, with Olympic runner Usain Bolt shown representing human achievement.

lesser fat-tailed jerboaIndian

elephant

Usain Bolt

Africanelephant

horse

aurochs

ostrich

foxhare

Severtzov jerboa

zebra

bison

cheetahgnu

onager

40

30

20

15

10

7

5

10 g 100 g 1 kg 10 kg

body mass

umax(m/s)

100 kg 1 t 10 t

Label the statements below as supported by the data in the diagram (S) or unsupported by the data in the graphs (U).

a. The heavier you are, the faster you can run.

b. A body mass of between approximately 30 to 100 kg is optimal for speed.

c. A cheetah has a larger maximum velocity to body mass ratio than a gnu.

d. Humans are an exception to the trends relating body mass and maximum velocity.

(4 marks)

11

Question 2

The diagram below represents displacement from the rest position of a point on a guitar string as it is allowed to oscillate freely over time.

Finger pluck excitation signal obtained via inverse filtering of guitar sample

0–0.8

–0.6

–0.4

–0.2

0

0.2

0.4

0.6

0.8

2 000 4 000 6 000 8 000 10 000 12 000 14 000 16 000

Sketch the graph of sound energy produced over time on the graph paper provided on page 25 of your response book.

(2 marks)

Question 3

Respond to this question on page 25 of your response book.

The diagram below shows two wave forms travelling in opposite directions with speeds as indicated. The wave coming from the right has half the amplitude of the wave coming from the left.

0 1 2 3 4 5

6 7 8

2.0 ms–1

2.0 ms–1

(distances in metres)

Use the principle of superposition to sketch the wave shapes 1.0 second after the time indicated on the graph.

(4 marks)

t (units)

disp

lace

men

t (un

its)

12

Question 4

The table below contains temperature data for an experiment measuring temperature vs height in the Earth’s atmosphere.

Height h (metres)

Temperature T (ºC)

0 15500 11.8

1000 8.51500 5.32000 22500 –1.33000 –4.53500 –7.84000 –114500 –14.35000 –17.55500 –20.86000 –24

a. Plot this information on the axes provided on page 26 of your response book.

b. Using the data from part a and the graph below, estimate the lowest temperature in the atmosphere and state in which atmospheric layer it occurs.

120 000

110 000

100 000

90 000

80 000

70 000

Alti

tude

(m)

60 000

50 000

40 000

30 000

20 000

10 000

0Lower temperature Higher temperature

Thermosphere

Mesosphere

Stratosphere

Troposphere

(5 marks)

13

Question 5

Two housemates are discussing how best to dry clothes as they share the job of hanging washing on a line. One says that the most important factor is wind, while the other maintains it is direct exposure to sunlight.

Design an experiment that determines which, if either, housemate is correct.

(5 marks)

Part B continues

14

Question 6

The diagram below shows how temperature and ocean salinity (amount of dissolved salt) vary as a function of latitude (distance either side of the equator).

30°C

38%

36%

34%

32%

20°C

10°C

0°C

80°N 80°S

Temperature

Salinity

23°NTropic of Cancer

0°Equator

23°STropic of Capricorn

A scientist claims, from looking at the first graph, that generally the warmer the ocean waters, the higher the salinity, noting also that a section of the graph does not support that claim. You, as a colleague of this scientist, have access to a second graph, shown opposite.

15

Use your knowledge of the second graph to support or otherwise critique the scientist’s claim with justification. Provide a possible explanation for the section of the first graph that does not support the claim. Write your justification and explanation on page 28 of your response book.

0.5

00 10 20 30 40 50 60 70 80 90–10–20–30–40–50–60–70–80–90

Precipitation rate vs latitude

2009200019901980197019601950

SouthernOceans Southern Canada,

Northern Europe& Northern Asia

SouthernSouth America

& Australia

Central North America &

Central Asia

2.5

3.5

4.5

5.5

6.5

3

4

5

6

1.5

1

2

(5 marks)

End of Part B

End of Paper One

16

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Queensland Curriculum & Assessment AuthorityPO Box 307, Spring Hill QLD 4004 AustraliaLevel 7, 154 Melbourne Street, South BrisbaneT + 61 7 3864 0299

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