NAME: ………………………………….

 

CARESA EDUCATION SERVICES

 

TRIAL  HIGHER  SCHOOL  CERTIFICATE EXAMINATION

 

2003

PHYSICS

2 UNIT

 

Time allowed – Three hours

(Plus 5 minutes reading time)

 

DIRECTIONS TO CANDIDATES

 

Section I – Core

 

*Attempt  ALL questions.

 

*Part A           15 multiple choice questions, each worth 1 mark.

                        Mark your answers in pencil on the Answer Sheet provided.

 

*Part B           Core questions worth a total of 60 marks.

                        Answer this part in spaces provided in your examination book.

 

*Write your name on your question book for part A, your answer sheet for part A and your question and answer book for part B.

 

Section II – Option

 

*          Answer one option only.

 

*          Questions are provided for the Astrophysics and Quanta to Quarks options only.

 

*          The option is worth 25 marks.

 

*          Answer the option on separate paper.

 

*          Write your name on each option answer sheet.

 

*          You may ask for extra paper if you need it.

 

*          A periodic Table, list of formulae and Data Sheet are provided at the back of this paper.

 

 

PART A.

Questions 1 – 15 are worth 1 mark each.

Mark your answers on the Answer Sheet provided.

Select the alternative A, B, C or D that best answers the question.

 

  1. An object has a weight of 49N on Earth. What is its mass and weight on Jupiter where  g = 25 ms-2?

 

Mass (kg)

Weight (N)

A

49

1225

B

49

49

C

5

49

D

5

125

 

 

  1. What is the potential energy of a 1.0 kg mass 1.0 km above the surface of the Earth?

 

A.    9800J

B.     –9800J

C.     6.27x107J

D.    –6.27x107J

 

3.         Luke was on a sailing boat and climbed to the top of the mast as a vantage point to get a better photo. The boat was moving forward at a steady 10 knots and Julie was watching from the shore. Unfortunately Luke dropped the camera. What path would the camera appear to follow as observed by Julie from the shore?

 

A.    Parabolic path forwards.

B.     Parabolic path backwards.

C.     Straight line, vertically down.

D.    Straight line, at an angle to the vertical.

 

 

4.         Michelson & Morely performed an experiment in which they tried to demonstrate the existence of the aether. What was the reason put forward by scientists at that time to justify the existence of the aether?

 

A.    Light waves needed a medium through which to travel.

B.     The speed of light is the same in all directions.

C.     The speed of light is independent of the motion of the source and observer.

D.    Time dilation could not occur if there was no aether.

 

 

 

 

 

 

 

5.                  A satellite is in uniform circular motion about the Earth. What is the direction of the net force acting on the satellite at the instant shown in the diagram?

 

 

A.

 

 


            B.

 

 


      C.

 

 

 


D

 

 

6.

Oval: xOval: x                                                I1                                                      I2

                                                                                                  

 

 

                                                            *P

I1 and I2 represent two wires, each carrying a current into the page. The direction of the magnetic field at P is

 

 


(A)

 

 

 


(B)

                       

 

 

(C)

 

(D)

 

 

 

 

 

7.                  Which of the following changes will NOT produce a change in the torque of a coil in a magnetic field?

 

A.    Changing the strength of the magnetic field.

B.     Changing the magnitude of the current.

C.     Changing the number of turns in the coil.

D.    Changing the shape of the coil.

 

8.                  When is the magnetic flux cutting the coil of a simple D.C. electric motor greatest?

 

A.    When the coil is parallel to the magnetic field.

B.     When the coil is perpendicular to the magnetic field.

C.     When the coil is at 45o to the magnetic field.

D.    There is no variation of the magnetic flux cutting the coil.

 

9.                  Which of the following characteristics applies to an A.C. induction motor?

 

A.    They have low efficiency, resulting in a lot of lost energy.

B.     They have a stationary magnetic field.

C.     Current is transferred to the coil by means of brushes and slip rings.

D.    They can be adjusted to work on D.C. by changing the commutator.

 

10.              An ideal transformer is one in which there is no power loss. However transformers are not ideal and the power output is less than the power input. What is the main reason for the loss in power of a step-up transformer?

 

A.    The back emf opposes the supply emf in the secondary coil.

B.     Eddy currents are produced in the core and produce heat energy.

C.     What is gained in voltage is lost in current.

D.    The wires in the secondary coil are thinner and can’t carry as much current as the primary coil.

 

11.              The band theory is a theory put forward to explain the behaviour of conductors, semiconductors and insulators. Which of the following statements about the band theory is correct?

 

A.    Conductors have a full conduction band and an empty valency band.

B.     Semiconductors have no electrons in the conduction band unless they are heated to overcome the forbidden energy gap.

C.     Electrons in insulators cannot be made to overcome the forbidden energy gap.

D.    Semiconductors have some electrons in the conduction band at room temperature.

 

 

 

 

 

 

 

12.       Cathode rays are fired between the poles of magnets as shown.

            What is the direction of the force on the cathode rays?

 

A.    Towards the top of the page.

B.     Towards the bottom of the page.

C.     Towards the north pole of the magnet.

D.    Towards the south pole of the magnet.

 

13.       Sir William Henry Bragg and Sir William Laurence Bragg were awarded the Nobel Prize in 1915 for their work in determining crystal structure. What was the method they used to study the structure of crystals?

 

A.    Diffraction of electrons.

B.     Diffraction of X-rays.

C.     Refraction of electrons.

D.    Refraction of X-rays.

 

14.       The point P lies above a beam of cathode rays moving to the right as shown.

 

                                                * P

                            cathode rays

 

            What is the direction of the magnetic field at P due to the cathode rays?

 

A.  Into the page

B.     Out of the page.

C.     Towards the right.

D.    None as there is no magnetic field.

 

15.              What would happen if a semiconductor such as silicon was doped with a small amount of a group V element such as arsenic?

 

A. It would gain a negative charge.

B. It would gain a positive charge.

C. It would remain neutral.

D. It would allow Cooper pairs of electrons to form.

 

 

 

 

NAME: ……………………………………….

 

PART  B

The marks allocated to each question are shown.

Answer this Part in the spaces provided in your examination book

Show all necessary working.

Marks may be awarded for relevant working.

 

16. Pluto has a mass of 0.002 that of Earth and a radius 0.18 that of Earth.

(i) What is the value of the acceleration due to gravity on the surface of Pluto? (2 marks)

 

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(ii) What would be the escape velocity from the surface of Pluto? (2 marks)

 

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17. The orbital velocity of a satellite in a stable orbit decreases as the distance from the centre of the Earth increases. Why is it that as a satellite slows down due to friction with low-density air, its distance from the centre of the Earth decreases as its orbital velocity decreases? (2 marks)

 

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18. Explain how the slingshot effect can be used to increase the speed of a spacecraft.

(3 marks)

 

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19.Describe the method used by Michelson & Morley in their attempt to measure the relative velocity of the Earth through the aether. (3 marks)

 

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20.       Describe a thought experiment involving mirrors and trains and discuss the relationship between thought and reality. (5 marks)

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21.       A spaceship which has a mass of 100 tonnes (105 kg) on Earth is travelling at 0.90c.

(i) What is its mass as observed by someone on Earth? (1 mark)

 

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 (ii) How much work is required to accelerate the spaceship from 0.90c to 0.95c?               (2 marks)

 

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22.       This question refers to the following diagram.

                       

A rectangular coil WXYZ is 20 cm long and 10 cm wide as shown. The coil has 200 turns of wire and lies parallel to a uniform magnetic field of 0.2 Tesla. A current of 5.0 amps flows through the coil in the direction WXYZ.

1. Calculate the force on a single wire on the side WX.  (2 marks)

 

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2. Calculate the torque due to the force on a single wire on the side WX.  (1 mark)

 

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3. Calculate the total torque on the coil.  (1 mark)

 

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23.       (i)         With the aid of a diagram, explain how induction is used in cooktops in electric

 ranges.  (2 marks)

 

 

 

 

 

 

 

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 (ii) State one way in which induction electric cooktops are safer than conventional electric cooktops. (1 mark)

 

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24. William placed three saucepans of water on his new induction cooktop. After a few minutes the water in the cast iron saucepan was boiling furiously, the water in the aluminium saucepan was lukewarm and the water in the glass saucepan was cold. Explain why the water in the different saucepans heated by different amounts.  (2 marks)

 

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25.       Electricity is carried through transmission lines at high voltage to minimise energy loss. Explain how a high voltage will reduce energy loss.  (3 marks)

           

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26.       Describe how you could perform an investigation to model the generation of an electric current by moving a magnet in a coil or a coil near a magnet. Include a table showing possible results for the variables that you are investigating.  (8 marks)

 

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27.       Prior to Thomson’s experiment in which he measured the charge to mass ratio of cathode rays, there was debate among scientists such as Hertz and Crookes as to whether cathode rays were particles or electromagnetic waves. Compare the evidence suggesting that cathode rays were particles with that suggesting that they were electromagnetic waves.  (4 marks)

 

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28. (i)   Describe Hertz’s observation of the photoelectric effect.  (2 marks)

 

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(ii)  Explain how the photoelectric effect suggests that light consists of particles.  (3 marks)

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29.       Compare the passage of electrons through aluminium at room temperature to that through aluminium below its critical temperature of 1.2K.  (4 marks)

 

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30.       How many photons of wavelength 600 nm would be required each second to produce a power output of 5 W?  (2 marks)

 

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31.       Describe how superconductors and the effects of magnetic fields have been applied to develop a maglev train.  (3 marks)

 

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32.       Assess the impact of transistors on society with particular reference to their use in microchips and microprocessors.  (2 marks)

 

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OPTIONS.

 

ATTEMPT ONE OPTION ONLY

 

Each option is worth 25 marks.

ASTROPHYSICS

 

Attempt All parts of this question.

 

32.       (i)         Calculate the distance in parsecs of a star that has a trigonometric parallax of   

                        0.01 seconds of arc.  (1 mark)

 

(ii)        Outline how adaptive optics, interferometry and active optics can improve the resolution and/or sensitivity of ground-based telescopes.   (3 marks)

 

(iii)       Suppose you used an accurate spectroscope to examine light from the Sun, a tungsten filament lamp (normal light globe) and mercury vapour lamp. Outline the ways the spectra from these three sources would differ.   (3 marks)

 

(iv)       Compare the spectrum produced by a galaxy to that produced by a star such as the Sun.  (2 marks)

 

(v)        Hadar (b-Centauri) has an apparent magnitude of  0.60 and is 390 Pc away. What is its absolute magnitude?   (2 marks)

 

(vi)       What is photometry?  (1 mark)

 

(vii)      What advantages do photoelectric technologies have over photographic methods of photometry?   (2 marks)

 

(viii)     Distinguish between astrometric binary stars and spectroscopic binary stars. 

(2 marks)

 

(ix)       Omega Centauri is a globular cluster and Kappa Crucis (also known as the Jewel Box) is an open cluster. In what ways would these two clusters be different?           (3 marks)

 

(x)        With reference to the H-R diagram, discuss differences in the evolutionary track of stars of 1, 5 and 10 solar masses.  (6 marks)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FROM QUANTA TO QUARKS

 

Attempt All parts of this question.

 

33.       (i)          Describe the Rutherford model of the atom.   (1 mark)

 

(ii)        The limitations of classical physics gave birth to quantum physics. What is the difference between classical physics and quantum physics?  (2 marks)

 

(iii)       Hydrogen shows a large number of spectral lines, the visible ones being part of the Balmer series where nf = 2.

Calculate the frequency of radiation emitted when an electron drops from ni = 3 to nf = 2 and also from ni = 10 to nf = 2.

                        What type of radiation is emitted by the drop from ni = 10 to nf = 2?    (3 marks)

 

 (iv)      What was de Broglie’s proposal and how was it confirmed by Davisson and Germer?  (3 marks)

 

(v)        How fast would an electron be moving if it had a wavelength of 10-10 m?

(2 marks)

 

(vi)             Describe Fermi’s initial experimental observations of nuclear fission. (3 marks)

 

(vii)      Name a radioactive isotope used in agriculture and describe its use.  (2 marks)

 

(viii)     Neutron scattering is a method used to study the structure of matter. Discuss the advantages and limitations of neutron scattering.  (3 marks)

 

(ix)       Outline the key features and components of the standard model of matter. 

(6 marks)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

16.  The diagram below represents one loop of a coil in a simple D.C. electric motor.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Which of the following graphs shows the relationship between the force on the side WZ and time for one revolution of the coil WXYZ from its initial horizontal position?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

a.                                           A wire is connected in a circuit and a current flows through it. If the potential difference across the circuit is increased so that more current flows through the wire, what happens to the drift velocity of the electrons?

 

A.    It increases.

B.     It decreases.

C.     It remains the same.

D.    More information is required to determine what happens to the drift velocity.

 

 

 

 

 

 

 

 

 

 

 

 

 

              i.                                                      The following diagram represents three parallel wires, X, Y and Z carrying currents of 5A, 5A and 10A respectively in the same direction.

 

 

 

 

 

 

 

 


                             X         Y                     Z

 

 

            The separation between X and Y is 10 cm and between Y and Z is 20 cm.

            What is the direction of the force on wire Y, the middle wire?

 

(a)    To the left.

(b)   To the right.

(c)    Into the page.

(d)   None as the net force is zero.

 

 

ii.                                                                        Why is an electric motor more likely to burn out when it jams rather than when it is running freely?

 

(a)    The back e.m.f. produces an increase in current.

(b)   The coil has less resistance when it is not moving.

(c)    Eddy currents cause the coil to heat up.

(d)   The net potential difference across the coil increases.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

iii.                                                                        A potential difference is applied to two metal plates as shown. Y is a point midway between the plates and X is midway between Y and the positive plate.

 

 

 

 

 

 

 

            Which of the following statements is correct?

 

(a)    The electric field strength at X is greater than the electric field strength at Y.

(b) The electric field strength at X is less than the electric field strength at Y.

(c) The electric field strength at X is the same as the electric field strength at Y.

(d) It depends on the voltage between the plates whether the electric field strength at X or Y is greater.

 

iv.                                                                        Which of the following represents the property of a superconductor in a strong magnetic field?

 

(a)    It has a higher critical temperature than with no magnetic field.

(b)   It has a lower critical temperature than with no magnetic field.

(c)    It will itself exhibit stronger magnetic field.

(d)   It will lose its superconducting qualities.

 

v.                                                                        The resistance of conductors and semiconductors changes with temperature. Which of the following situations occurs when the temperature increases.

 

 

Semiconductor e.g. Si

Conductor e.g. Cu

A

Resistance increases

Resistance increases

B

Resistance increases

Resistance decreases

C

Resistance decreases

Resistance increases

D

Resistance decreases

Resistance decreases

 

vi.                                                                        In 1915 W. H. Bragg  and his son W. L. Bragg  were awarded the Nobel Prize for their analysis of crystal structure by diffraction techniques.

What kind of beams did they use in their experiment?

 

(a)    Light

(b)   X-rays

(c)    Electrons

(d)   Radio waves

 

 

 

 

15.    A television screen produces a picture by scanning a beam across the picture tube.

         What are the beams composed of?

 

(a)    High frequency electromagnetic waves.

(b)   Low frequency electromagnetic waves.

(c)    Light rays

(d)   Cathode rays

 

16.        In 1875 Sir William Crookes used a cathode ray tube containing a Maltese Cross and produced a shadow of the cross on the front of the tube.                                             

What did this experiment demonstrate about cathode rays?

 

(a)    Cathode rays are particles.

(b)   Cathode rays travel in straight lines.

(c)    Cathode rays have an electric charge.

(d)   Cathode rays are electromagnetic radiation similar to light.

 

17.       A beam of electrons is deflected as it passes through an electric field as shown.

 

 

 

 

 

 

 

 

 

What would be the direction of a magnetic field that would act with this electric field to let the beam of electrons pass through undeflected?

 

(a)    Towards the top of the page.

(b)   Towards the bottom of the page.

(c)    Into the page.

(d)   Out of the page.

 

 

 

 

 

 

 

 

 

 

17.              This question refers to the following diagram.

Hertz found that when he applied a high voltage across a spark transmitter he was also able to produce sparks in a receiver loop.

By shining U.V. rays onto the receiver loop the intensity of the spark in the receiver loop was increased.

What was the reason for the increased intensity of the spark in the receiver loop that was produced by the U.V. rays?

 

(a)    The photoelectric effect.

(b)   Thermionic emission.

(c)    Increased radio waves.

(d)   Electron diffraction.

 

18.              Two experimental cavity radiators were constructed to approximate the performance of black bodies. The shape and size of the radiators were identical but different materials were used for each cavity radiator. The first radiator was made of copper and the second was made of aluminium. Copper is a better thermal conductor and also a better electrical conductor than aluminium.

 

 

 

 

 

 

 

 

 

Which of the following statements correctly describes the radiation emitted from each radiator when each is heated to the same temperature?

 

(a)    No radiation would be emitted from either hole as they are both black bodies.

(b)   The radiation emitted from the copper would have a longer wavelength than that emitted from the aluminium.

(c)    The radiation emitted from the copper would have a shorter wavelength than that emitted from the aluminium.

(d)   The radiation emitted from both radiators would be identical.

 

19.              Yellow light is found to emit photoelectrons from a metal with kinetic energy Ek and current I.  What will be the effect on the kinetic energy of the photoelectrons and on the current if the intensity of the yellow light is increased so that it is brighter?

 

 

Kinetic Energy Ek

Current I

A

Same

Same

B

Increase

Same

C

Same

Increase

D

Increase

Increase

 

 

20.              Germanium was used to manufacture early transistors whereas silicon is used to manufacture present day transistors.      

What is the reason that silicon was not used in early transistors?                                                                             

(a)    Technology had not been developed that enabled silicon to be used in transistors.

(b)   Germanium was less expensive than silicon.

(c)    Germanium was used in thermionic devices that transistors replaced.

(d)   Silicon could not be obtained in sufficiently pure form.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NAME: ……………………………………….

 

 

PART  B

 

The marks allocated to each question are shown.

Answer this Part in the spaces provided in your examination book

Show all necessary working.

Marks may be awarded for relevant working.

 

21.              A trip to a fun park with a roller coaster is much less expensive than a rocket launch.  Compare the forces acting on an astronaut during launch with the forces acting on a person during a roller coaster ride. (3 marks)

 

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22        Describe a simple experiment you could perform to determine if you were in an inertial frame of reference.  (2 marks)

 

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23.              What is the difference between Einstein’s theory of general relativity and his theory of special relativity.  (1 mark)

 

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24.              The importance of the Michelson-Morely experiment was its null result. What is the role of such an experiment in making determinations about competing theories.           (2 marks)

 

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25.              One of the most dangerous parts of a space flight is the re-entry into the Earth’s atmosphere.

Discuss issues associated with safe re-entry into the Earth’s atmosphere. (3 marks)

 

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26.              With reference to Lenz’s law explain why an electric motor or generator can never be 100% efficient. (2 marks).

 

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27.              What is the role of transformers in electricity sub stations?  (1 mark)

 

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28.              The diagram below shows a moving coil meter.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Describe the principles of the moving coil meter that enable it to measure the current flowing through a circuit. (5 marks)

 

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29.              A D.C. motor requires a commutator to operate effectively.  Describe the construction and operation of the commutator in a typical D.C. electric motor. (4 marks)

 

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30.       Discuss how semiconductors can be used to make solid state components that replace thermionic devices and describe the advantages of these solid state components.            (5 marks)

 

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31.              In 1892 the German scientist Heinrich Hertz was of the opinion that cathode rays were electromagnetic radiation yet British scientists a few years later demonstrated that they were particles.

Discuss the evidence that suggested that cathode rays were electromagnetic radiation and outline the experimental evidence that caused scientists to conclude that they were particles. (5 marks)

 

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32.              Describe the differense between conductors, semiconductors and insulators in terms of band structures and relative electrical resistance. (3 marks)                                                           

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33.       Discuss Einstein’s and Planck’s debate about whether science research is removed from social and political forces. (3 marks)

 

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34.              Tin is a fairly good conductor but becomes a superconductor below its critical temperature of about 3.7K. Outline how the lattice of tin impedes the path of electrons causing heat to be generated but below 3.7K electrons pass through unimpeded with no energy loss. (4 marks)

 

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OPTION: FROM QUANTA TO QUARKS

 

(a)        James Chadwick is credited with discovering the neutron yet the experiment that led to its discovery was first performed by Frederic and Irene Joliot.

Outline how Chadwick interpreted the Joliot experiment to verify the existence of the neutron. (3 marks)

 

(b)               Name a nucleon that has no charge. (1 mark)

 

(c)                In 1930 Wolfgang Pauli predicted the existence of the neutrino yet it was not actually detected until an experiment by Cowan and Raines in 1956.

What led Pauli to predict the existence of the neutrino? (3 marks)

 

(d)       Define the term “transmutation”. (1 mark)

 

(e)        In 1808 John Dalton wrote; “Atoms of different elements cannot be changed from one into the other.”

Evaluate this statement with reference to the beta decay of carbon-14. (2 marks)

 

(f)        A student said to you that the protons in the nucleus were held together by gravitational attraction that just balanced the electrostatic force of repulsion.  With reference to the relative contributions of electrostatic and gravitational forces between nucleons explain why you would disagree with the statement. (2 marks)

 

(g)        How do the properties of the strong nuclear force vary with distance between nucleons.

Draw a graph (numerical values not required) to show this relationship. (3 marks)

 

(h)        An atom bomb and a nuclear reactor both produce nuclear reactions, but whereas the first is an uncontrolled, fast reaction the second is a controlled, much slower reaction. Compare the requirements for these two types of nuclear reactions. (3 marks)

 

(i)         An equation for the fission of uranium-235 is:

92U235 + 0n1           92U236               57La148 + 35Br85 + 3 0n1

 

If the masses of the atoms in this equation are:

92U235 = 235.044 a.m.u.

57La148 = 147.915 a.m.u.

35Br85 = 84.911 a.m.u.

0n1 = 1.009 a.m.u.

1 a.m.u. = 1.66 x 10-27 kg

 

(I) Calculate the mass defect in a.m.u. for the fission of 1 atom of uranium (1 mark)

(II) Calculate the energy released in joules from the fission of 1 atom of uranium.              (2 marks)

 

(j)         In 1934 Enrico Fermi irradiated uranium with neutrons. The product emitted beta particles and Fermi thought it was an isotope of uranium. Later work however showed that the product was consistent with being composed of smaller nuclei such as barium and lanthanum.

What was the name of the type of nuclear reaction that Fermi produced? (1 mark)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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