2018 Senior External Examination

PhysicsPaper One — Question book

Thursday 1 November 20189 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 — Multiple-choice response sheet• Paper One — Response book• Paper One — Resource book

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

DirectionsDo not write during perusal time.Paper One has two parts:

• Part A — Knowledge of subject matterSection 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 sessionThe supervisor will collect 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).

Section 1 is worth 15 marks. Section 2 is worth 25 marks.

Suggested time allocation: 1 hour and 30 minutes.

Section 1 — Multiple-choiceSection 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 1Einstein’s equation linking mass and energy is given below.

E=mc2

where in this case:

Mass (m) = 0.032 g

Speed of light (c) = 3 0 108 1

. × −ms

How many significant figures should be present in the answer?A OneB TwoC ThreeD Four

Question 2The graph below shows the change in velocity over time for an object.

According to the graph, the object first experienced its maximum force atA 0 s.B 2 s.C 4 s.D 6 s.

2

Question 3A person travels 60 m in a straight line in 10 s, rests for another 10 s and then travels 50 m in the opposite direction in 20 s. Their average velocity is

A 0.25 ms–1.

B 2.75 ms–1.

C 3.50 ms–1.

D 4.25 ms–1.

Question 4The gravitational attraction between two bodies is given by the equation below. G is the universal gravitational constant; M is the mass of one of the bodies; m is the mass of the other body; and d is the distance between their two centres of mass.

2GMmF

d=

If both bodies increased their mass by a factor of 2 and their separation is also increased by a factor of 2, by what factor would the original gravitational force be multiplied to describe the new gravitational force between them?

A 0

B 1

C 2

D 8

Question 5After leaving a rifle, a bullet travels horizontally at 800 ms–1. It reaches its target 1 second later. Its vertical velocity as it hits the target is

A 0.0 ms–1.

B 1.0 ms–1.

C 800 ms–1.

D 9.8 ms–1.

Question 6The relationship between force and extension for a spring is given by the equation

F kx=where F is force and x is displacement. The units of k are therefore

A kg s.

B kg m s.

C kg s–2.

D kg m s2.

3

Question 7In a longitudinal wave, the direction of energy flow

A is perpendicular to any temporary displacement of mass.

B is in the same direction as any temporary displacement of mass.

C depends on the maximum temporary displacement of mass.

D depends on the phase of the wave.

Question 8Four different devices are set up and the current flowing through them and the potential difference across them were recorded and displayed on the following graphs.

Which of the devices has a constant resistance?

A Device A

B Device B

C Device C

D Device D

4

Question 9Magnetic flux is a measure of

A the angle of a magnetic field to an area of space.

B the area of space through which field lines pass.

C how the magnetic field fluctuates in any given area of space.

D the intensity of a magnetic field passing through any given area of space.

Question 10Assuming a power source with a constant voltage and an identical task, an electric drill with a rating of 500 W

A draws more current than a 650 W drill.

B has a higher resistance than a 650 W drill.

C uses less voltage than a 650 W drill.

D expends the same amount of energy in the same time as a 650 W drill.

Question 11An electric field line that connects two point charges is only possible if

A the two charges are positive.

B the two charges are negative.

C one charge is positive and one charge is negative.

D the two charges are of different magnitude.

Question 12A magnetic field exists around a current carrying wire that is pointing into the page at X as indicated in the diagram below.

Which of the following claims is not true?

A A field line connects C to D.

B The field is weaker at A than D.

C The field strength at points A and B is the same.

D The field at D points upwards.

5

Question 13The circuit below can act as

A a PNP transistor.

B a full wave rectifier.

C a half wave rectifier.

D an amplifier.

Question 14The element represented by 94 X is

A fluorine.

B aluminium.

C boron.

D beryllium.

Question 15The effectiveness of carbon-14 dating does not extend typically beyond eight half-lives. The fraction of the original carbon-14 left after this time is approximately

A 5 104× − .

B 7 104× − .

C 2 103× − .

D 4 103× − .

End of Section 1

6

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

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

Question 1State the number of significant figures in each of these examples.

i. 0.0056

ii. 30 07 104. × −

(1 mark)

Question 2Convert the percentage error into an absolute error.

200 ± 3 %

(1 mark)

Question 3A 500 kg rocket travelling at 50 ms–1 experiences a constant force in the direction of motion of 250 N for 30 s. Calculate the final velocity of the rocket.

(3 marks)

Question 4A go-cart and rider weigh 120 kg together. From rest, the cart rolls from the top of a 15 m high hill down the slope, gathering speed as it goes until it reaches the bottom. Calculate the maximum possible speed of the cart at the bottom of the hill.

(3 marks)

Question 5Two in-phase point sources, A and B, generate audible sound waves as indicated in the diagram below, in which the full lines indicate compressions and the dotted lines indicate rarefactions. Using the terms ‘loud’ and ‘soft’, describe how the sounds change as a person walks in a straight line from P to Q.

(3 marks)

7

Question 6In a Young’s double-slit experiment, light was passed through two slits 0.235 mm apart and a pattern of bright and dark fringes appeared on a screen 4.00 m away. The distance between pairs of adjacent bright fringes was found to be a constant 1.00 cm. From this data determine the wavelength of the light used in the experiment.

(3 marks)

Question 7How much work is done in moving a charge of 1 5 10

12. × − C across a potential difference of 2.5 kV?(3 marks)

Question 8A label from an air conditioner is shown below.

WINDOW TYPE AIR CONDITIONERMODEL CCINVR 37COOLING CAPACITY 12660 KJ/hHEATING CAPACITY ———EXCESSIVE OPERATING PRESSURE

DISCHARGE 4.8 MPaSUCTION 1.7 MPa

POWER SOURCE 220–230 V ~ 60 Hz, 1PhREFRIGERANT R32/480 g

STANDARDRATINGCONDITIONS

COOLINGCURRENT 4.5 AINPUT 1005 W

HEATINGCURRENT ———INPUT ———

ELECTRICAL HEATER INPUT ———OUTSIDE RESISTANCE CLASS IP 24

CROWNE-AIRE

Calculate the resistance of the air conditioner.

(3 marks)

Question 9A proton having a charge of 1 6 10

19. × − C enters a magnetic field of strength 1.5 T at an angle of 60 degrees to the field lines with a velocity of 5 0 10

3 1. × −ms . Calculate the force experienced by the

proton as a result of interacting with the field.(3 marks)

Question 10When the cobolt-60 isotope decays to nickel-60 gamma radiation is emitted.

What other type of radiation is produced?(2 marks)

End of Section 2End of Part A

8

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 1The diagram below shows information regarding relative respiratory and lung volumes typical of humans.

The following text explains the sections of the diagram.

TV The tidal volume is the total amount of air inhaled or exhaled during regular respiration or relaxed breathing.

IRVAn inspiratory reserve volume is a supplementary volume, approximately ranging between 2 500 to 3 100 mL of air, which could be effectively inhaled after the inspiration of a standard tidal volume.

ERV An expiratory reserve volume refers to the additional capacity of air, which is about 1 200 mL that could be forcibly exhaled after the expiration of a standard tidal volume.

RV The residual volume is the total volume of air 1 100 mL to 1 200 mL, residing in the lungs after the reserve volume is emitted or breathed out.

TLC The total lung capacity applies to the total volume of air in the lungs after a forced inspiration. The lung capacity of a healthy man is estimated to be 6 000 mL.

VC The vital capacity is the total volume of air that can be expired after maximum inhalation and is approximately 80 percent of TLC.

IC The inspiratory capacity is the total volume of air that can be inspired, which is about 3 600 mL.

FRC The functional residual capacity is the total volume of air residing within the lungs after an exhalation process, and it is about 2 400 mL.

Label the equations and statements below as supported or unsupported by the data in the diagram.

a. FRC = ERV + RVb. FRC = VC – ERVc. The residual volume (RV) of the lungs can be forcibly exhaled.d. The tidal volume of the lungs is approximately 500–1 000 mL.

(4 marks)

9

Question 2Respond to this question on page 26 of your response book. Spare diagram is provided on page 28.

The diagram below shows a ray of light travelling through a semicircle block of glass. The glass has a higher optical density than air. The dotted line is at right angles to the base and goes through point P, the centre of the radius of curvature.

Sketch a plausible path for the ray before it enters the block and after it leaves.

(2 marks)

Question 3Respond to this question on page 26 of your response book. Spare diagram is provided on page 28.

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

Sketch the wave shapes 1.0 second after the starting position shown in the diagram.

(4 marks)

10

Question 4Respond to this question on page 27 of your response book. Spare grid and response space are provided on page 29.

The table below contains temperature data for an experiment measuring coffee temperature versus time. Trials 1 and 2 involved adding milk to the coffee at different times as indicated by the double asterisk.

Temperature (°C)

Time (min) Trial 1 Trial 2

0 67 67

1 64 65

2 63** 64

3 54 63

4 53 62

5 52 60

6 51 59

7 50 58

8 49 57

9 48 56

10 48 55

11 48 54

12 47 53**

13 47 45

14 45 45

15 45 43

a. Plot the data in the table on the axes provided in the response booklet. Include a key to indicate which lines represent which trials.

b. Suggest from this data whether it is better to place milk in coffee earlier or later to keep the temperature as high as possible for drinking immediately after the experiment.

(6 marks)

Question 5Two students are arguing about whether a person would get wetter by running across a given uncovered length of ground if it is raining or by walking at a normal pace. They are also concerned that the length that has to be traversed is an important factor to consider.

Design an experiment that will address these issues.

(6 marks)

11

Question 6Respond to this question on page 27 of your response book. Spare diagram is provided on page 29.

The diagram below shows the voltage versus time relationship for a coil rotating in a magnetic field. The internal resistance of the coil is 1.6 Ohms.

On the same graph sketch the current versus time in the coil.

(3 marks)

End of Part BEnd of Paper One

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