view_agenda
Questions
Find the perfect question by filtering through every previous QCAA Physics external exam question
notifications
Question Classifications
We’re conducting a final review of the classifications and formatting for our recently onboarded questions. If you have any feedback, please share it with us here.
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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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.
No results found
open_with