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Girraween High School
2020 HIGHER SCHOOL CERTIFICATE TRIAL EXAMINATION
Physics
General Instructions
- Reading Time – 5 minutes
- Working Time – 3 hours
- Write using black pen
- Draw diagrams using pencil
- Calculators approved by NESA may be used
- A data sheet, formula sheet and Periodic Table are provided
Total marks: 100
Section I – 20 marks (pages 1 – 9)
- Attempt questions 1 – 20
- Allow about 35 minutes for this section Section II – 80 marks (pages 10 – 26)
- Attempt questions 21 – 37
- Allow about 2 hours and 25 minutes for this section
4 Calculate the energy released from an electron-positron annihilation. (A) 8.19 × 10−14^ eV (B) 1.638 × 10−13^ eV (C) 0.51 MeV (D) 1.02 MeV
5 A man stands on a train moving at an extremely high velocity, v , pointing a torch in the direction of motion. A woman stands next to the track. A metre ruler lies on the floor of the train as shown.
Which of the following correctly describes an observation that could be made?
(A) Both observers would measure the speed of light and length of the rule to be the same. (B) The woman observes the ruler to be less than one metre and the speed of light to be ( c + v ) (C) The man observes the speed of light to be ( c – v ) and the metre rule to be one metre long. (D) Both observers measure the speed of light be c , but do not agree on the length of the ruler.
6 What is the energy of a photon of blue light with wavelength 475 nm? (A) 475 J (B) 4.18 x 10-19^ J (C) 3.15 x 10-40^ J (D) 1.05 x 10 -48^ J
Metre ruler
7 Light from a green laser passes through a double-slit arrangement, as seen below. An interference pattern is observed on the screen.
Which of the following actions would increase the spacing between the bands? (A) Increasing the separation of the laser and the double slit. (B) Decreasing the distance between the double slits and the screen. (C) Changing from a green laser to a blue laser. (D) Changing from a green laser to a red laser.
8 A permanent bar magnet is dropped from rest through a number of hollow solenoids, as shown in the diagrams below. All solenoids have the same length. Two of the solenoids have a connecting wire between the ends of the solenoid. In which case would the magnet experience the greatest resistive force as it passes into the solenoid?
200 coils 500 coils
200 coils 500 coils
12 An electron moving with a velocity of 3.0 × 10^3 ms -1^ passes at 90° through a magnetic field of strength 2 × 10 -2^ T. Identify which expression gives the magnitude of force on the electron due to the magnetic field. (A) F = 1.602 × 10-19^ × 3000 × 0.02 × sin 90° (B) F = 1.602 × 10-19^ × 3000 × 200 × sin 90° (C) F = 1 × 3.0 × 10 3 × 2 × 10-2^ × cos 90° (D) F/l = 1.602 × 10-19^ × 3000 × 200 × cos 90°
13 What is the main advantage that follows from the use of transformers in power systems? (A) Transformers allow the high voltages at which power is generated to be stepped down to usable levels. (B) Transformers allow voltages to be stepped up so that larger currents can be generated and transmission efficiency can be improved. (C) Transformers allow the low voltages at which power is generated to be stepped up to usable levels. (D) Transformers allow voltages to be stepped up for transmission with lower currents so that transmission efficiency can be improved.
14 A bar magnet is lowered at constant speed through a wire ring, as shown in the diagram.
Which of the following graphs best represents the variation of the current induced in the ring, 𝐼𝐼, with time, 𝑡𝑡?
15 A powerful light is shone onto a metallic surface in a vacuum but initially no electrons are observed emitted from the surface. Which of the following circumstances is most likely to follow? (A) Electrons are emitted after sufficient time has passed for them to accumulate enough energy from the light. (B) Electrons are emitted after increasing the power of the light. (C) Electrons are emitted after decreasing the frequency of the light. (D) Electrons are emitted after decreasing the wavelength of the light.
16 Two long conductors are suspended parallel as shown in the diagram below. The current in both wires is equal, but opposite in direction.
The distance, d, between the two wires is decreased at a steady rate. Which graph below shows how the force between the wires will change over time?
d
I 1
I 2
20 Plane-polarised light is incident normally on a polariser which is able to rotate in the plane perpendicular to the light as shown below.
In diagram 1, the intensity of the incident light is 8 W m -2^ and the transmitted intensity of light is 2 W m -2^. Diagram 2 shows the polariser rotated 90º from the orientation in diagram 1. What is the new transmitted intensity? (A) 0 W m - (B) 2 W m - (C) 6 W m - (D) 8 W m -
2020 EXAMINATION HIGHER SCHOOL CERTIFICATE TRIAL
Physics Section I – Multiple Choice Answer Sheet
1. A B C D
2. A B C D
3. A B C D
4. A B C D
5. A B C D
6. A B C D
7. A B C D
8. A B C D
9. A B C D
10. A B C D
11. A B C D
12. A B C D
13. A B C D
14. A B C D
15. A B C D
16. A B C D
17. A B C D
18. A B C D
19. A B C D
20. A B C D
Student Number
Instructions for answering questions in Section I
- Complete your answers in either blue or black pen
- Multiple choice Select the alternative A, B, C or D that best answers the question. Fill in the response oval completely. Sample 1: 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 change your mind and have crossed out what you consider to be the correct answer, then indicate the correct answer by writing the word correct and drawing an arrow as follows. A B C D correct
Question 21 (5 marks) A GPS satellite with a mass of 11 000 kg orbits the Earth at an altitude of 20 000 km. a) Calculate the magnitude of its gravitational potential energy. 2
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b) Calculate its orbital velocity. 3
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Question 22 (5 marks) A catapult releases its projectile 4.0 m above the ground with an initial velocity of 50 ms-1 at 40° to the horizontal, as shown in the diagram below.
a) Determine the maximum height reached above the ground by the projectile. 2
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Question 22 (continued)
b) What is the range of the projectile? 3
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Question 23 (3 marks) Solar activity generates streams of very fast charged particles that travel outwards into space. a) A relativistic electron is generated by such activity and travels towards the Earth at 0.9 times the speed of light. If the Earth–Sun distance is 150 000 000 km, calculate how long it takes the electron to get here as measured on the Earth.
b) How much time would have passed in the reference frame of the electron? 2
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End of Question 23
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Question 26 (6 marks) The diagram below shows the end-on view of a simple DC motor, consisting of a square coil of 20 turns, within a uniform magnetic field of 2.5 × 10-2^ T provided by permanent magnets.
The square coil of side length 5 cm and it is situated at an angle of 25º to the field. The current in the coil is 0.45 A and is directed away from the observer on side A.
a) Determine the force acting on side B, including its direction. 2
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b) Calculate the torque acting on the coil in the position shown. 2
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c) What will be the effect of adding extra coils at regular angles on the operation of the motor? 2
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End of Question 26 Please turn over
Question 27 (3 marks) Assuming a transformer is close to 100 per cent energy efficient, explain how energy is conserved if the transformer is used to step voltage down.
Question 28 (4 marks) Outline the requirements necessary for a satellite to orbit the Earth in a geostationary orbit. Include any relevant calculations in your answer.
End of Question 28 Please turn over
Question 30 (4 marks) One of the cathode ray tubes you studied contains a metal cross as shown in the picture below.
a) Describe the observations a student would be able to make when observing this tube in operation.
b) Identify two inferences that can be made from the observations made from the cathode ray tube. 2
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Question 31 (4 marks) The CERN physics program uses powerful accelerators such as the Large Hadron Collider (LHC) and detectors to study fundamental particles. Some huge amounts of electrical energy are consumed when the LHC is in operation and accelerating protons.
Each proton in the LHC is typically accelerated to reach 0.999c before it collides into another proton travelling in the opposite direction at the same speed.
a) Determine the relativistic momentum of a colliding proton in the LHC. 2
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b) The LHC seeks, among other things, to give clarity to aspects of the Standard Model of matter. Part of that model includes quarks and the composite particles known as hadrons. With reference to the Standard Model, describe the composition of a proton.
End of Question 31 Please turn over
