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QUESTION 6 The definition of relativistic momentum is the (A) momentum of an object when measured in a Newtonian frame of reference. (B) momentum of an object when measured regardless of its frame of reference. (C) momentum of an object when measured in the frame of reference in which the object is in motion. (D) momentum of an object when measured in the frame of reference in which the object is stationary.
QUESTION 7 A quantum of any form of electromagnetic radiation is also known as (A) a photon. (B) an X-ray. (C) apositron. (D) an electron.
QUESTION 9 Select the list containing the six types of quarks. (A) 1n out up down top and bottom (B) right left charm strange in and out (C) up down charm strange top and bottom (D) charm strange right left top and bottom
QUESTION 10 The force that quarks experience that leptons do not is the (A) weak force. (B) strong force. (C) normal force. (D) electromagnetic force.
QUESTION 13 The Rutherford atomic model describes an atom (A) as the smallest particle of any substance. (B) with a small dense nucleus surrounded by orbiting electrons. (C) consisting of electrons scattered throughout a sphere of positively charged fluid. (D) consisting of a small positive nucleus surrounded by negative electrons in set orbits of fixed energy.
QUESTION 14 Select the list that contains only gauge bosons. (A) gluon photon meson and hadron (B) lepton baryon meson and hadron (C) gluon photon Z boson and W boson (D) Z boson W boson photon and lepton
QUESTION 16 According to the theory of special relativity the concept of simultaneity is best described as (A) when two events occur at the same time. (B) when an observer sees two events occurring at the same time. (C) two events observed to happen at the same time in a particular frame of reference. (D) the relation between two events assumed to happen at the same time when observed from any frame of reference.
QUESTION 20 Calculate the frequency of light that would be required to eject a photoelectron at a velocity of 1.90 x 10° m s~ from a metal plate with a work function of 4.73 eV. (A) 1.14 x 10 ° Hz (B) 1.34x 10 Hz (C) 248 x10° Hz (D) 3.62 x 10'° Hz
QUESTION 22 (1 mark) List the six types of leptons. 1. 2 3.
QUESTION 23 (2 marks) Twin astronauts conduct an experiment where one travels with a velocity close to the speed of light to a distant planet while the other stays on Earth. Each twin expects the other to be a different age by the time the first twin reaches and remains on the distant planet. Use the theory of special relativity to explain why the twins will no longer be the same age and draw a conclusion about which twin will be younger.
QUESTION 24 (4 marks) A spaceship travelled from Planet A to Planet B at a speed of 0.90c. An observer that was stationary relative to both planets measured the time taken for the trip to be 4.0 years. Calculate the time taken for the trip as measured by an observer on the spaceship.
QUESTION 26 (3 marks) A photoelectric effect experiment was conducted by shining different frequencies of light on a plate made of an unknown metal. The graph shows the kinetic energies of ejected photoelectrons with respect to the frequency of incident light. 25 20 15 Kinetic energy (eV) Incident frequency (101 Hz) The table shows the work functions of various metals. Work function (eV) Determine which metal 1s most likely to have ejected the photoelectrons in this experiment.
QUESTION 27 (4 marks) The diagram shows a small section of the emission spectrum for a mixture of gases. 565 569 575 582 587 594 600 Wavelength (nm) The diagram shows the atomic energy level diagram for a gas known as Element A. 7 ronisation 145eV N\ _147eV _3.54¢V 5.74 eV Determine whether it is possible that Element A is one of the gases in the mixture.
QUESTION 1 (1 mark) Explain why an object with mass cannot travel at the speed of light in a vacuum.
QUESTION 3 (5 marks) The diagram shows the atomic energy levels of the atoms in an unknown gas. T/ Tonisation -13¢eV 2.7 eV 4.1eV -5.6 eV Predict the shortest wavelength of visible light that could be emitted from this unknown gas. (Note: The range of visible wavelengths of light is between 400 nm and 700 nm.) Wavelength = nm
QUESTION 4 (5 marks) Describe how experiments on the photoelectric effect provide evidence of the quantised nature of photons.
QUESTION 7 (3 marks) A photoelectric effect experiment is conducted by shining different frequencies of light on a sample of aluminium. The kinetic energy of the ejected photoelectrons was measured. The data is plotted in the graph. > S N > e 0 a o o = 2 o p _2 n -3 4 -5 6 Incident frequency (10'* Hz) Identify the mathematical relationship between kinetic energy £ and incident frequency /.
QUESTION 1 Leptons do not experience the (A) weak force. (B) strong force. (C) gravitational force. (D) electromagnetic force.
QUESTION 3 Identify the correct formula for the massenergy equivalence relationship. A) E= me? (B) E=mgh ©) E=Lime? 2 (D) E= %mv2
QUESTION 5 Mesons are (A) subatomic particles composed of one quark and one antiquark. (B) elementary particles that are classified as leptons. (C) elementary particles exchanged between quarks. (D) subatomic particles composed of three quarks.
QUESTION 9 The Bohr atomic model describes an atom as (A) the smallest particle of any substance. (B) a small dense nucleus orbited by electrons. (C) electrons scattered throughout a sphere of positively charged fluid. (D) a small positive nucleus surrounded by negative electrons in set orbits of fixed energy.
QUESTION 10 Proper length is the length measured in the frame of reference where the object is (A) atrest. (B) 1n motion. (C) accelerating. (D) 1n motion but not accelerating.
QUESTION 15 Which Feynman diagram shows an electron interacting with another electron? (A) (B) Space Space Time Time © (D) Space Space Time Time
QUESTION 19 A spaceship with a velocity of 9.0 X 10 m s! is measured to be 125 m in length by an observer at rest. Calculate the length of the spaceship as measured by somebody on board the spaceship. (A) 119m (B) 131 m (C) 137m (D) 178 m
QUESTION 20 A photoelectron with a kinetic energy of 2.5 X 1077 s ejected when a photon with a frequency of 1.3 x 10 Hz is incident on the metal plate. Calculate the threshold frequency of light required to eject the photoelectron from the metal plate. (A) 6.1 x 107 Hz (B) 3.7 x 10 Hz () 92 x 10 Hz (D) 17 x 10 Hz
QUESTION 26 (5 marks) A physicist has identified the absorption spectrum of an unknown atom. L 421 491 523 Wavelength (nm) The diagram shows the atomic energy levels for three atoms. Atom 1 Atom 2 Atom 3 V0020022 s 7500 T D007 e ge = tige T ties -3.40 eV _ 360eV _ -350eV 13.59 eV -14.02¢V -13.78¢V Not to scale Determine which atom is most likely to be the unknown atom.
QUESTION 2 (1 mark) List the four gauge bosons in the Standard Model. 1. 2 3. 4
QUESTION 8 (4 marks) A photoelectric effect experiment was conducted by shining light from a laser at one frequency on five different metals with known work functions. The graph shows the maximum kinetic energy of the photoelectrons ejected from each metal with respect to their work functions. 4.5 4 pe e N W w W p DN Kinetic energy (10_19J ) 5 6 Work function (10~ 19y ) Determine the wavelength of the light emitted by the laser. Wavelength = nm (to the nearest whole number)
QUESTION 9 (3 marks) Explain how Youngs double slit experiment provides evidence for the wave model of light.
QUESTION 2 A photon is described as (A) a continuous wave of light energy. (B) a particle that can only propagate in a medium. (C) a quantum of all forms of electromagnetic energy. (D) a particle that mediates the forces between protons.
QUESTION 5 Tau particles are classified as (A) bosons. (B) leptons. (C) mesons. (D) baryons.
QUESTION 6 After coherent light has been passed through a double slit the observation of an interference pattern on a screen 1s explained by the (A) wave nature of light. (B) equal width of the slits. (C) discrete packets of photons. (D) distance from the slits to the screen.
QUESTION 8 Determine the wavelength of an electromagnetic wave with an energy of 2.4 x 10722 J. (A) 72x10 P m (B) 2.8x10'!'m (C) 83x107°m (D) 1.2x10*m
QUESTION 11 The maximum kinetic energy of an electron ejected from a metallic surface can be increased by (A) using a positively ionised metal. (B) using a metal with a larger work function. (C) increasing the intensity of the incident light. (D) decreasing the wavelength of the incident light.
QUESTION 14 Which Feynman diagram correctly depicts neutron decay? (A) Space (B) Space (©) Space (D) Space Time
QUESTION 15 An objects velocity can only be measured relative to (A) a fixed reference frame. (B) the speed of light. (C) an object at rest. (D) an observer.
QUESTION 20 Which option lists the gauge bosons in ascending order of the strength of force they mediate? (A) W boson < Z boson < Photon (B) Gluon < Z boson < W boson (C) Photon < W boson < Gluon (D) Z boson < Photon < Gluon
QUESTION 21 (2 marks) A hot iron bar was observed to have a deep red colour. As the iron bar was heated further the colour changed to orange. Explain the observed colour change in terms of black-body radiation.
QUESTION 22 (2 marks) A collection of mesons was observed by a detector to move an average distance of 11.0 m when travelling at 95% of the speed of light. However based on their properties the mesons were expected to travel an average distance of 3.4 m. Explain the difference between the observed and expected average distances.
QUESTION 23 (6 marks) The diagram shows the electron energy levels for hydrogen. [onisation n=>6 -0.38 eV n=>5 -0.54 eV n=4 -0.85eV n=3 1.51eV n=2 -3.40 eV n=] -13.60eV Ground level a) Calculate the energy released in joules when an electron moves from the third to the first energy level. Show your working. [3 marks] Energy released = J (to three significant figures) The visible light emission spectrum for hydrogen is shown. o 410 434 486 656 Wavelength (nm) b) Explain why hydrogen only has four emission spectrum lines in the visible (i.e. 400700 nm) spectrum. [3 marks]
QUESTION 26 (1 mark) Carbon-14 undergoes nuclear decay to nitrogen-14. 1§C 1?N+e_ + 7 List the two types of particles whose total number must be conserved in this reaction.
QUESTION 1 (2 marks) Two spaceports are stationary relative to each other. Astronaut A moves from one spaceport to the other at relativistic speed and observes the lights on both spaceports turn off at the same time. Astronaut B is at a stationary position equally distant relative to each spaceport and observes the lights turn off one after the other. Explain why the astronauts view these events differently.
QUESTION 2 (2 marks) Contrast the properties of up quarks and tau particles.
QUESTION 5 (3 marks) The Feynman diagram for a particle interaction is shown. Space Time Describe the particle interaction taking place.
QUESTION 1 The correct definition of lepton number is (A) the total number of leptons in a particle interaction. (B) a conserved quantum number defined by L = n; ny. (C) the number of leptons remaining after a particle interaction. (D) astrictly conserved additive quantum number of a system defined by B = é (ng ng).
QUESTION 3 Select the option that contains the two correct postulates of special relativity. (A) The laws of physics are the same in all inertial frames of reference and the speed of light in a vacuum has the same value c in all inertial frames of reference. (B) The laws of physics are the same in all inertial frames of reference and the relation between two events is assumed to happen at the same time in all inertial frames of reference. (C) The relation between two events is assumed to happen at the same time in all inertial frames of reference and the laws of physics are not the same in all inertial frames of reference. (D) The relation between two events is assumed to happen at the same time in all inertial frames of reference and the speed of light in a vacuum has the same value ¢ in all inertial frames of reference.
QUESTION 5 The graph below presents the results of a photoelectric effect experiment. It shows the maximum kinetic energy of photoelectrons (Ey) with respect to the frequency of incident photons (f). = Photoelectric effect experiment N S % 80 SA) & 6.0 2 5 50 2 o 40 5 Z 30 = g 20 8 < 10 = 2 00 g 0.0 20 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 > < 14 S Frequency f (x 10 Hz) The gradient of the linear trend line shown in the graph above represents (A) Plancks constant. (B) the work function. (C) the threshold frequency. (D) the power of the light incident on the metal surface.
QUESTION 8 Which of the following is a correct consequence of the speed of light in a vacuum being the same for all observers? (A) The frame of reference of the observer is always the real frame of reference. (B) Observations of events in distant galaxies are observations of events that occurred in the past. (C) A clock that is moving relative to an observer will tick faster than a clock that is at rest in the observers own frame of reference. (D) When measured by a stationary observer the length of a moving object is smaller than the length of the object when it is measured in its own frame of reference.
QUESTION 10 Which model of the atom would predict the continuous emission of electromagnetic energy resulting in the instability of the atom? (A) Bohrs model of the atom (B) Daltons model of the atom (C) Rutherfords model of the atom (D) Thomsons plum pudding model of the atom
QUESTION 11 A rocket with a velocity of 0.9 ¢ journeys from Earth to a distant planet. An observer on Earth measures the journey to have taken 3.00 years. Calculate the time taken for the journey as measured by a clock on the rocket. (A) 0.95 years (B) 1.31 years (C) 6.88 years (D) 9.48 years
QUESTION 12 Which two gauge bosons mediate the weak nuclear forces? (A) gluon and photon (B) gluon and Z boson (C) photon and Z boson (D) W boson and Z boson
QUESTION 14 The correct definition of the term antiparticle is (A) aparticle with a known substructure. (B) aparticle with no known substructure. (C) anparticle with the same mass and opposite charge and/or spin as a corresponding particle. (D) aparticle with a different mass and the same charge and/or spin as a corresponding particle.
QUESTION 17 The Feynman diagram below represents an interaction of particles. Space Time Select which particle interaction is represented by the diagram above. (A) aneutron decaying into a proton (B) aproton decaying into a neutron (C) an electron and electron interaction (D) an electron and positron interaction
QUESTION 18 Select the list that only contains quarks. (A) (B) ©) (D) down charm top and strange muon up down and neutrino meson gluon photon and boson anti-up anti-neutrino charm and strange
QUESTION 21 (1 mark) Define the term baryon.
QUESTION 24 (3 marks) Explain one possible interaction between an electron and a positron. Clearly label the Feynman diagram below to support your answer. Space Time Note: If you make a mistake in the diagram cancel it by ruling a single diagonal line through your work and use the additional diagram on page 10 of this question and response book.
QUESTION 26 (2 marks) Youngs double slit experiment provides evidence for the wave model of light. Identify one piece of evidence and explain why this supports the wave model of light.
QUESTION 4 (5 marks) The graph below shows the results of a photoelectric effect experiment where the photoelectrons were ejected from an unknown metal plate. Photoelectric effect data o L L N N . oo o N ~ (@)} (00} N o 4 Maximum photoelectron kinetic energy Eyx (X 1077 ]) | N Frequency f (X 10 Hz) The table below shows the work functions of various metals. Work function W (eV) a) Identify the mathematical relationship between Ey and f using the information from the graph on page 6. Show your working. [3 marks] b) Draw a conclusion from the data about which metal is most likely to have ejected the photoelectrons in this experiment. Show your working. [2 marks]
QUESTION 5 (6 marks) Below are two diagrams. The diagram on the left shows the energy level diagram for an unknown gas while the diagram on the right shows the emission spectra for three different elements (A B and C). Energy level diagram Emission spectra 413 nm 496 nm 590 nm Energy (eV) .Z /__/__/ Z /_Z .Z /_ lonisation Element A D:I:D > )(nm) g g -2.7¢eV on Nel AN < <r > )\ (nm) -5.7 eV g § c c c on S o o N <r w w -8.2¢eV &8 m8m8m8m8m8m > L (nm) Draw a conclusion as to which emission spectra would be produced from the unknown gas. Support your answer with calculations. (Note: Do not include transitions from ionisation to any of the energy levels.)
QUESTION 6 (5 marks) Below is an image of Youngs double slit experiment and a graph showing the intensity and wavelength of light emitted from a black body. Youngs double slit experiment Black-body radiation curve X - |'-| Classical theory Min. \ Max \ Min. \ | Max \ Min g ! Light source @ | :[ d Max. g i \\ Min. ! \ ) Max. i AN | Min. E Max. i Min. i Max. ; Screen Wavelength Describe waveparticle duality of light by referring to the evidence above.
QUESTION 8 (8 marks) A ladder measured at 20 m in length when stationary is carried horizontally by Observer A at a velocity of 0.9 c through a barn. The barn is 15 m long and has an open door at either end. Observer B sitting in the barn presses a button when they see that the ladder has completely entered the barn. Observer B sees both the front and rear barn doors instantaneously close and then open again at the same time the button is pressed. Explain how this could be viewed as a paradox and conclude whether the ladder will make contact with the barn doors. Support your explanation and conclusion with calculations.
QUESTION 1 An object is unable to accelerate to the speed of light because (A) length contraction will change the height of the object. (B) time dilation will decrease the velocity of the object. (C) the object will gain infinite momentum. (D)_ the inertia of the object will decrease.
QUESTION 2 Photons are (A) (B) (C) (D) gauge bosons that exhibit wave characteristics. particles that can only travel in a medium. mediators of the weak nuclear force. leptons with no charge.
QUESTION 5 Young’s double slit experiment demonstrates that light (A) behaves differently in different frames of reference. (B) shares characteristics with mechanical waves. (C) isa longitudinal wave. (D) acts like a particle.
QUESTION 7 An electron and positron can annihilate into a photon producing another electron and positron pair in the process. An outcome of this interaction is that (A) total mass decreases. (B) fewer baryons will be produced. (C) the lepton number does not change. (D) the number of particles will decrease.
QUESTION 8 Incident light with a frequency of 1.70 10!° Hz is shone onto a metal surface with a work function of 1.00 10718 J. Determine the kinetic energy of a photoelectron ejected from the metal surface. (A) 7.9x101 eV (B) 1.7x10°P eV (C) 13x10’ ev (D) 2.0x10°% eV
QUESTION 10 A black body at a temperature of 6040 K produces photons across a range of frequencies. Calculate the frequency at which the maximum number of photons is produced. (A) 6.3x10!4 Hz (B) 2.1x10° Hz (C) 4.8x107’ Hz (D) 1.6x10°° Hz
QUESTION 12 What is a consequence of symmetry in particle interactions? (A) (B) (C) (D) The law of conservation of momentum is obeyed. Charges on particles will always be different. Antiparticles travel backwards through time. Total mass of the particles will decrease.
QUESTION 14 An electron is best described as a (A) lepton with a larger mass than a positron. (B) baryon with a smaller mass than a proton. (C) meson that experiences the strong nuclear force. (D) particle whose interactions can be mediated by photons.
QUESTION 16 A train is travelling at relativistic speed and is about to move through a tunnel. An observer on the train measures the train and tunnel to each be 95 m long. A second observer is stationary relative to the tunnel. They would observe the train to (A) simultaneously enter and exit the tunnel. (B) decrease its mass while in the tunnel. (C) move faster while in the tunnel. (D)_ be shorter than the tunnel.
QUESTION 17 The half-life of an unstable subatomic particle is measured by a stationary detector to be longer when its velocity approaches the speed of light. This is because the particle (A) is moving relative to its frame of reference. (B) isin the same frame of reference as the detector. (C) experiences time differently relative to the detector. (D) cannot be accurately observed at relativistic speeds.
QUESTION 20 The energy level diagram for a simple atom is shown. UMMM Bed) n=4 3.4 n=3 ~6.0 n=2 -13.6 n= | —— 54.4 Not to scale What transition is allowed for an electron that absorbs a photon with a frequency of 6.3 «10!4 Hz? (A) n=l1ton=3 (B) n=l1ton=4 (C) n=2ton=3 (D) n=3ton=4
QUESTION 21 (4 marks) Describe how the atomic model proposed by Bohr addresses the limitation of Rutherford’s model.
QUESTION 23 (1 mark) List the forces that can be experienced by leptons.
QUESTION 25 (3 marks) An observer who is stationary relative to a moving spaceship measures the velocity of the spaceship to be 2.0x108 ms . Calculate the length of the spaceship if the observer records it as 18 m. Show your working. Length = m (to two significant figures)
QUESTION 26 (4 marks) Calculate the energy (in electron volts) of a photon with a wavelength of 405 nm. Show your working. Energy = eV (to three significant figures)
QUESTION 28 (2 marks) The Feynman diagram for a neutron decaying into a proton and electron is shown. Space Time Describe the significance of the electron antineutrino in this particle interaction.
QUESTION 1 (3 marks) Describe the effects of relativistic travel on an object.
QUESTION 5 (4 marks) Describe what happens when light is shone onto a metallic surface in the context of the photoelectric effect.
QUESTION 7 (5 marks) Discuss the nature of light by describing evidence from two key experiments.
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