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First teaching 2014

Last exams 2024

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Discrete Energy & Radioactivity (DP IB Physics: SL)

Exam Questions

3 hours44 questions
1
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Which of the statements is the correct definition of excitation of an electron?

  • When an electron is removed from or added to an atom

  • When an electron moves down an energy level emitting a photon

  • When an electron is given enough energy to move up an energy level, but not enough to leave the atom

  • When an electron is given enough energy to move up an energy level, and sometimes leave the atom

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The diagram below shows the energy levels of a mercury atom.

7-1-discrete-energy--radioactivity-sl-mcqs-easy-q2-question-diagram-1

Which transition produces a photon with the longest wavelength?

7-1-discrete-energy--radioactivity-sl-mcqs-easy-q2-question-diagram-2

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    3
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    The diagram shows an energy–level diagram for a hydrogen atom.

    7-1-discrete-energy--radioactivity-sl-mcqs-easy-q3-question-diagram

    How many discrete photon energies could be produced from these energy levels?

    • 3

    • 5

    • 6

    • 7

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    4
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    Which of the following is not a feature of an emission spectrum?

    • When an electron transitions from a higher energy level to a lower energy level, this results in the emission of a photon

    • An emission spectrum contains a set of discrete wavelengths, represented by coloured lines on a black background

    • An emission spectrum is evidence to show that electrons in atoms can only transition between discrete energy levels

    • An emission spectrum consists of a continuous spectrum containing all the colours with dark lines at certain wavelengths

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    5
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    A larger version of the hydrogen emission spectrum from the infrared to the ultraviolet region looks as follows:

    7-1-discrete-energy--radioactivity-sl-mcqs-easy-q5-question-diagram

    Using information in the diagram, which hydrogen series corresponds to the highest energy photons being emitted?

    • Lyman series

    • Balmer series

    • Brackett series

    • Pfund series

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    6
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    An isotope of Am presubscript 95 space end presubscript presuperscript 241 space end presuperscript  undergoes alpha-decay. 

    Which letter on the N-Z graph below represents the correct proton-neutron product of the decay?

    7-1-discrete-energy--radioactivity-sl-mcqs-easy-q6-question-diagram

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      7
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      Uranium−238 undergoes radioactive decay to become Thorium−234. A second decay occurs and the product is protactinium−234.

      The decay sequence can be represented in equation form, where i, j and k are particles.:

       

      straight U presubscript 92 presuperscript 238 rightwards arrow Th presubscript 90 presuperscript 234 space plus space i

Th presubscript 90 presuperscript 234 rightwards arrow Pa presubscript 91 presuperscript 234 space plus space j space plus space k

        

      What are the correct names of these particles?

       

      i

      j

      k

      A

      alpha

      beta−minus

      electron anti−neutrino

      B

      beta−positive

      beta−minus

      alpha

      C

      beta−minus

      neutron

      photon

      D

      alpha

      beta−positive

      neutron

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        8
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        What are the correct numbers of protons, neutrons and electrons in a neutral atom of U presubscript 92 presuperscript 234?

         

        protons

        neutrons

        electrons

        A

        92

        92

        92

        B

        92

        142

        92

        C

        142

        92

        142

        D

        234

        142

        92

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          9
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          What is the charge on, and mass of, an electron neutrino and during what process is an electron neutrino produced?

           

          charge /e

          mass / u

          production of neutrino

          A

          +1

          zero

          during β+ emission

          B

          −1

          +1

          during β emission

          C

          zero

          zero

          during β+ emission

          D

          zero

          0.0005

          during β emission

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            10
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            A sample of californium−239 has an activity of 4000 Bq. The half−life of californium−239 is 1 minute.

            What will the activity be after 4 minutes?

            • 4000 Bq

            • 1000 Bq

            • 500 Bq

            • 250 Bq

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            1
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            size 16px U presubscript size 16px 92 presuperscript size 16px 238 decays to thorium-234 by emitting an alpha particle and two gamma rays. Thorium-234 then decays into protactinium via beta decay.

            Which point on the N-Z graph below represents the position of the granddaughter nucleus, protactinium?

            q1

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              The half-life of carbon-14 is 6000 years.

              An ancient elephant tusk has been uncovered and its age is unknown. A 20 g sample of the tusk has an activity of 1.25 Bq due to carbon-14.

              A 80 g sample of tusk taken from a living elephant has an activity of 20 Bq.

              Use this information to determine the age of the ancient tusk.

              • 3000 years

              • 12 000 years

              • 18 000 years

              • 24 000 years

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              3
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              Fluorodeoxyglucose is a compound used as a tracer in medical imaging. The isotope fluorine-18 is used, which is a positron emitter.

              The way these positrons interact with electrons in the body allows PET (positron emission tomography) scanners to determine the rate of respiration certain cells are performing.

              Fluorine-18 decays into an isotope of oxygen.

              Which equation below represents the correct nuclear equation for this decay?

              • F presubscript 9 presuperscript 18 rightwards arrow O presubscript 8 presuperscript 18 plus beta presubscript plus 1 end presubscript presuperscript 0 plus upsilon subscript e

              • F presubscript 9 presuperscript 18 rightwards arrow O presubscript 9 presuperscript 18 plus beta presubscript plus 1 end presubscript presuperscript 0 plus upsilon subscript e

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              4
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              Protactinium-231 (scriptbase P a end scriptbase presubscript 91 presuperscript 231) is a radioactive element, it decays by alpha radiation and then beta-minus decay as shown below:

               Error converting from MathML to accessible text.

              What proton number and mass number will element B have?

               

              Proton Number

              Mass Number

              A.

              89

              229

              B.

              90

              229

              C.

              89

              227

              D.

              90

              227

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                5
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                The energy levels of an atom are shown in the diagram below.

                q15_discrete-energy-_-radioactivity_ib-sl-physics-mcq

                Which transition will emit the photon with the shortest wavelength?

                • n = 4 to n = 1

                • n = 2 to n = 1

                • n = 2 to n = 1

                • n = 4 to n = 3 

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                A radioactive source is known to emit beta radiation. A Geiger-Muller tube is used to measure the count rate at increasing distances from the source.

                Which graph correctly represents the variation in count rate over these distances for beta radiation?

                q16_discrete-energy-_-radioactivity_ib-sl-physics-mcq

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                  Unstable nuclei make up 10% of a sample’s mass. The count rate of the sample is measured over a time period of 8 hours.

                  q17_discrete-energy-_-radioactivity_ib-sl-physics-mcq

                  After some time has passed, the percentage of the sample which is unstable reduces to 2.5%. What is the count rate of the source at this time?

                  • 90 cpm

                  • 60 cpm

                  • 45 cpm

                  • 30 cpm

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                  8
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                  A source is known to be radioactive but the type of radiation being emitted is unknown.

                  A Geiger-Müller tube is placed close to the source and different materials are placed between the two. A table of the count rates recorded for each material is shown below. The background count rate is 15 counts per minute.

                  Material

                  Count rate recorded / counts per minute

                  Paper

                  528

                  Nothing

                  1064

                  Thick lead

                  17

                  Aluminium

                  524

                  What types of radiation are being emitted by the source?

                  • alpha comma space beta and gamma

                  • alpha spaceonly

                  • beta spaceand gamma

                  • alpha and gamma

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                  9
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                  Hydrogen atoms feature energy levels as shown below.

                  q19_discrete-energy-_-radioactivity_ib-sl-physics-mcq

                  Which photon energy will not cause an electron to be excited or ionised in a ground state hydrogen atom?

                  • 10.2 eV

                  • 12.29 eV

                  • 12.75 eV

                  • 15.0 eV

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                  10
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                  Three of the four isotopes below are the same element. Which isotope represents a different element?

                   

                  Nucleon number

                  Neutron number

                  A.

                  233

                  141

                  B.

                  235

                  143

                  C.

                  238

                  146

                  D.

                  239

                  146

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                    1
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                    The energy level diagram below shows six possible transitions between the energy levels of an atom. Each transition between levels creates a photon of definite energy and frequency.

                    7-1-sl-mcq-hard-q1-phy

                    The increase in frequency is from left to right.

                    Which of the following spectrum corresponds most closely to the transitions?

                    7-1-sl-mcq-hard-q1_2-phy

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                      A particular nucleus, X presubscript Z presuperscript A decays to form Y presubscript z presuperscript a, which then has two possible decay paths, resulting in either an isotope of Thallium (Tl) or Polonium (Po), as shown.

                      7-1-sl-mcq-hard-q2-phy

                      Which isotope could not be straight X presubscript straight Z presuperscript straight A?

                      • Pb presubscript 82 presuperscript 215

                      • Po presubscript 84 presuperscript 214

                      • At presubscript 85 presuperscript 218

                      • Pb presubscript 82 presuperscript 214

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                      The decay series for Thorium–232 can be plotted as shown.

                      7-1-ib-sl-hard-mcqs-q3-question

                      According to the diagram, how many possible routes are available for Thorium–232 to decay to a stable nucleus of lead−208?

                      • 2

                      • 4

                      • 10

                      • 12

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                      The diagram shows the decay chain for a particular isotope.

                      7-1-sl-mcq-hard-q4-phy

                      What are the isotopes labelled 1, 2 and 3?

                       

                      1

                      2

                      3

                      A

                       T presubscript 90 presuperscript 230 h  A presubscript 85 presuperscript 218 t  P presubscript 82 presuperscript 210 b

                      B

                       U presubscript 92 presuperscript 234  A presubscript 85 presuperscript 218 t  P presubscript 82 presuperscript 210 b

                      C

                       U presubscript 92 presuperscript 234  P presubscript 84 presuperscript 218 o  T presubscript 81 presuperscript 210 l

                      D

                       T presubscript 90 presuperscript 230 h  P presubscript 84 presuperscript 218 o  P presubscript 82 presuperscript 210 b

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                        Polythene film is made by extruding polythene and drawing it into a long sheet which is wound onto a roll, as shown in the diagram below.

                        7-1-sl-mcq-hard-q5-phy

                        The manufacturer has to carefully choose a radioactive isotope which will effectively remove any electrostatic charge that has built up on the film. The manufacturer also has to consider the point X, Y or Z at which the radioactive isotope should be placed along the assembly line.

                        At which point should the radioactive isotope be placed, and which type of radiation should the manufacturer choose to remove excess electrostatic charge?

                          Point Type of radiation
                        A X alpha
                        B X gamma
                        C Y beta
                        D Z alpha

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                          Transitions between three energy levels in a particular atom give rise to the three spectral lines of frequencies, in decreasing magnitude f subscript 1, f subscript 2 and f subscript 3 with wavelengths lambda subscript 1, lambda subscript 2 and lambda subscript 3.

                          Which of the following correctly relates f subscript 1, f subscript 2 and f subscript 3 and lambda subscript 1lambda subscript 2 and lambda subscript 3

                            Frequency Wavelength
                          A. f subscript 3 equals f subscript 1 plus f subscript 2 1 over lambda subscript 1 equals 1 over lambda subscript 2 plus 1 over lambda subscript 3
                          B. f subscript 3 equals f subscript 1 minus f subscript 2 1 over lambda subscript 1 equals 1 over lambda subscript 2 plus 1 over lambda subscript 3
                          C. 1 over f subscript 1 equals 1 over f subscript 2 minus 1 over f subscript 3 lambda subscript 1 equals lambda subscript 2 plus lambda subscript 3
                          D. 1 over f subscript 1 equals 1 over f subscript 2 plus 1 over f subscript 3 1 over lambda subscript 3 equals 1 over lambda subscript 1 minus 1 over lambda subscript 2

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                            7
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                            Radioactive isotopes are used in medical imaging.

                            For example, two isotopes of iodine, 123-I and 131-I are both used by radiographers, who give them to patients in the form of iodide before taking scans.

                            The possible decay equations for these isotopes are:

                            1. I presubscript 53 presuperscript 123 space rightwards arrow space T presubscript 52 presuperscript 123 e + _____

                                  2. I presubscript 53 presuperscript 131 space rightwards arrow space X presubscript 54 presuperscript 131 e + _____

                            Which is a correct difference between these two decays?

                            • In decay 1, an electron neutrino is emitted, but in decay 2 an anti-electron neutrino is emitted

                            • In decay 1, an electron has been absorbed but in decay 2 a neutron has been absorbed

                            • In decay 1, an anti-electron neutrino is emitted, but in decay 2 an electron neutrino is emitted

                            • In decay 1, a neutron became a proton but in decay 2 a proton became a neutron

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                            8
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                            The graph shows the how the neutron-proton ratio of stable nuclei changes as proton number increases.

                            7-1-sl-mcq-hard-q8-phy

                            What other changes with increasing proton number are suggested by the graph?

                            1. The charge-mass ratio increases
                            2. The charge-mass ratio decreases
                            3. The likelihood of α-decay increases
                            4. The likelihood of β-positive decay increases
                            5. Protons outnumber neutrons in large nuclei, with a rapidly increasing ratio
                            • 1 and 3

                            • 2 and 3

                            • 2, 4 and 5

                            • 2, 3 and 5

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                            The charge to mass ratio, Q over m, is also known as the specific charge.

                            What is the ratio of fraction numerator specific space charge space of space Li presubscript 3 presuperscript 7 space nucleus over denominator specific space charge space of space scriptbase straight O to the power of 2 plus end exponent space ion end scriptbase presubscript 8 presuperscript 16 end fraction?

                            • 6 over 7

                            • 7 over 6

                            • 24 over 7

                            • 7 over 24

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                            10
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                            The number of undecayed atoms, N, of a radioactive substance after time, t, can be calculated by the equation:

                            N equals N subscript 0 open parentheses 1 half close parentheses to the power of t over T subscript 1 half end subscript end exponent

                            Where:

                            • T subscript 1 half end subscript= the half-life 
                            • N subscript 0= the original number of atoms

                            Two radioactive elements X and Y have half–lives TX and TY respectively. An initial sample contains three times as many atoms of X, NX than atoms of Y, NY.

                            After a certain time, t, which of the expressions for fraction numerator n u m b e r space o f space d e c a y e d space a t o m s space o f space X over denominator n u m b e r space o f space d e c a y e d space a t o m s space o f space Y end fraction is correct?

                            • fraction numerator 3 open parentheses N subscript Y minus N subscript Y open parentheses begin display style 1 half end style close parentheses to the power of begin display style t over T subscript X end style end exponent close parentheses over denominator N subscript Y minus N subscript Y open parentheses begin display style 1 half end style close parentheses to the power of begin display style t over T subscript Y end style end exponent end fraction

                            • fraction numerator N subscript X open parentheses 1 half close parentheses to the power of t over T subscript X end exponent minus N subscript X over denominator N subscript Y open parentheses 1 half close parentheses to the power of t over T subscript Y end exponent minus N subscript Y end fraction

                            • fraction numerator N subscript X open parentheses 1 half close parentheses to the power of t over T subscript X end exponent over denominator N subscript Y open parentheses 1 half close parentheses to the power of t over T subscript Y end exponent end fraction

                            • fraction numerator 3 N subscript Y open parentheses 1 half close parentheses to the power of t over T subscript Y end exponent over denominator N subscript Y open parentheses 1 half close parentheses to the power of t over T subscript Y end exponent end fraction

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