# Band

## Band 1/2

### Module: From Ideas to Implementation

#### Student Responses (3)

Band 1/2 response 1 Band 1/2 response 2 Band 1/2 response 3

### Question 24

Section I Question 24 - 2002 HSC

In terms of band structures and relative electrical resistance, describe the differences between a conductor, an insulator and a semiconductor.

#### Student Responses (3)

Band 1/2 response 1 Band 1/2 response 2 Band 1/2 response 3

### Question 24-26

Written Paper Section I Question 24-26 - 2001 HSC

Q24. Describe one way in which an understanding of crystal structure has impacted on science. Outline the methods of X-ray diffraction used by the Braggs to determine the structure of crystals. Q25. Graph the results of measurements of frequency of incident radiation and photoelectron energy taken in an experiment on the photoelectric effect, including the line of best fit. Explain how the reliability of the experiment could be improved. Q26. In the context of semiconductors, explain the concept of electrons and holes.

#### Student Responses (3)

Band 1/2 response 1 Band 1/2 response 2 Band 1/2 response 3

### Question 25

Section I Question 25 - 2002 HSC

For two parallel metal plates that are separated by a fixed distance and have a given potential difference applied; (a) Calculate the magnitude of the electric field strength between the plates. (b) Calculate the magnitude of the electrostatic force acting on an electron between the plates, (c) If a beam of electrons is fired with a given velocity between the plates, calculate the magnitude and direction of the magnetic field that must be applied between the plates to cancel the force and stop the deflection of the electron beam.

### Module: Motors and Generators

#### Student Responses (3)

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### Question 21-23

Written Paper Section I Question 21-23 - 2001 HSC

Q21. Explain why no resistance is required when a large d.c. motor is running at high speed, but a substantial resistance is needed when the motor is starting up. Q22. Identify the direction of the force that exists between two parallel wires, each with a current flowing in the same direction along the wires. On a set of axes, sketch a graph that shows how the force between the two wires would vary if the length of the shorter wire were increased. Explain how these results demonstrate the moto-effect. Q23. Discuss the effects of the development of electrical generators on society and the environment. Outline the methods of X-ray diffraction used by the Braggs to determine the structure of crystals.

#### Student Responses (3)

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### Question 22

Section I Question 22 - 2002 HSC

(a) Identify the function of the brush in a generator. (b) Determine which of the generators illustrated is a DC generator and justify your choice. (c) Outline why AC generators are used in large-scale electrical power production.

#### Student Responses (3)

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### Question 23

Section I Question 23 - 2002 HSC

(a) State Lenz’s law. (b) Determine which end of a metal rod is negative if an electromagnetic field is induced between the two ends when it is moved through an illustrated magnetic field. Explain how the emf is produced in the rod. (c) Explain how the principle of induction can be used to heat a conductor.

### Module: Option: Astrophysics

#### Student Responses (3)

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### Question 30

Section II Question 30 - 2002 HSC

(a) Describe the observations made by astronomers on Earth to identify a star as an eclipsing binary. Explain how the total mass of a binary star system can be calculated. (b) Use a table showing distance, apparent visible magnitude and colour index; to determine which star is most blue in colour; to calculate the difference in brightness between two stars; and to sketch a labelled diagram indicating the information required to use the trigonometric parallax method to determine the distance to a star. Part (c) is not in the current syllabus. Describe a nuclear reaction taking place in a main sequence star. (d) Discuss how adaptive optics and at least one other development have improved resolution and sensitivity of ground-based astronomy.

### Module: Option: From Quanta to Quarks

#### Student Responses (1)

Band 1/2 response 1

### Question 30

Written Paper Section II Question 30 - 2001 HSC

(a) Define nucleon and contrast one property of nucleons. (b) Use the data provided in a table to calculate the energy of the photon emitted when an electron makes a transition between quantum levels. Draw the energy level diagram for hydrogen, indicating where the energy levels lie for quantum numbers greater than 4. Part (c) is not in the current syllabus. (d) Discuss the significance of the Manhattan Project for society. (e) Analyse how Chadwick’s and Fermi’s work resulted in a greater understanding of the atom.

### Module: Physics skills

#### Student Responses (3)

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### Question 16

Section I Question 16 - 2002 HSC

For an experiment to determine the acceleration due to gravity using a simple pendulum, (a) Outline TWO changes that could be made to the experimental procedure to improve its accuracy, (b) Compare two students' methods of calculating g and identify the better approach, (c) Calculate the value of g from the line of best fit on a graph.

#### Student Responses (3)

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### Question 20

Section I Question 20 - 2002 HSC

Using activities carried out in a boat on a large, calm lake and the observed results for each activity, justify the conclusion that: ‘The boat can be regarded as an inertial frame of reference’.

#### Student Responses (3)

Band 1/2 response 1 Band 1/2 response 2 Band 1/2 response 3

### Question 24-26

Written Paper Section I Question 24-26 - 2001 HSC

Q24. Describe one way in which an understanding of crystal structure has impacted on science. Outline the methods of X-ray diffraction used by the Braggs to determine the structure of crystals. Q25. Graph the results of measurements of frequency of incident radiation and photoelectron energy taken in an experiment on the photoelectric effect, including the line of best fit. Explain how the reliability of the experiment could be improved. Q26. In the context of semiconductors, explain the concept of electrons and holes.

### Module: Space

#### Student Responses (3)

Band 1/2 response 1 Band 1/2 response 2 Band 1/2 response 3

### Question 16-17

Written Paper Section I Question 16-17 - 2001 HSC

Q16. Name the effect demonstrated by the observation that high-speed muons have a lifetime of 5.0 microseconds but, when brought to rest, their lifetime is 2.2 microseconds; calculate the velocity of the muons as they leave the accelerator. Q17. Using a graph of velocity and time, compare the acceleration of a rocket launched vertically at t = 20s with its acceleration at t = 100s; account for the shape of the graph over the range of time shown.

#### Student Responses (3)

Band 1/2 response 1 Band 1/2 response 2 Band 1/2 response 3

### Question 18-20

Written Paper Section I Question 18-20 - 2001 HSC

Q18. Calculate the force acting on a projectile when it is at its maximum height after being fired from a cannon and the time it takes to reach the ground from its maximum height. Describe and compare the vertical forces at the object's maximum height with the forces on an identical object attached to a mechanical arm and moved at a constant speed in a vertical half-circle. Q19. Outline how Einstein’s Theory of Special Relativity explains the result of the Michelson–Morley experiment. Q20. Explain why transformers are used in an a.c. network between the generating stations and the final consumer.