Radiochemistry and Nuclear Chemistry self-test # 12

Comprises Chapter 12

This is a self grading test of your knowledge. It consists of 20 randomly chosen questions with single or multiple answers. The questions with single answers have round buttons and the questions with perhaps more than one correct answer have square buttons. Answer the questions by clicking on the corresponding button in the list of alternative answers. On questions with a single answer (round buttons to click on), it is only possible to mark one of the alternative answers as correct.
Grading of the completed test is automatic when you click on the button marked "GRADE MY ANSWERS" at the end of the test.
Correct answers can be read by clicking on the button having the same number as the question. You find these buttons at the end of the test. You can also refresh your memory first by jumping directly to the answer buttons and click on them to get answers and read relevant parts of the book before doing this test.
On the questions with one or more possible answers (squares to click on) only the first click on each button is recorded as an answer. Hence you must click on the reset button below the question before you can change the original answer(s). Failure to do this will probably make the answers on this question regarded as wrong in the grading process.
Please observe that your teacher may require a deeper understanding of the treated subject than reflected by this test. In case you have any valuable comments or questions regarding this self-test, explain them in an e-mail to: jol@nc.chalmers.se 

Question # 1 (One or more answers) When 252Cf decays it emits

    A) a-particles
    C) visible light
    D) muon-radiation
    E) neutrons

In case of an error in the answers above, please click on this button before making any corrections 

Question # 2 (One answer) The products from an exoergic nuclear reaction have

    A) never been observed
    B) higher kinetic energy than the reactants
    C) a velocity near that of light
    D) almost no velocity at all with regard to the center of mass
    E) a lather rest mass than the reactants

Question # 3 (One or more answers) The interaction between an atomic nucleus and a particle can result in

    A) elastic scattering
    B) light scattering
    C) inelastic scattering
    D) transmutation
    E) regression

In case of an error in the answers above, please click on this button before making any corrections 

Question # 4 (One answer) In order to produce rotationally excited nuclei one can use

    A) the vertical component of the Earth's gravitational field
    B) the Coulomb repulsion between uncharged nuclei
    C) neutron irradiation in a right angle relative the target nucleus
    D) Coulomb excitation
    E) tunneling below the nucleus

Question # 5 (One or more answers) The total energy in a system can be written as a sum of several energies. Which of the following should be included?

    A) Ekin 
    B) Ecoul 
    C) Eomass 
    D) Eexc 
    E) Ev 

In case of an error in the answers above, please click on this button before making any corrections 

Question # 6 (One or more answers) All conservation laws for nuclear reactions are not valid at extremely high projectile energies. Which of the following laws is usually not obeyed in such cases?

    A) the conservation of total energy
    B) the conservation of linear momentum
    C) the conservation of charge
    D) the conservation of mass number
    E) the conservation of total spin

In case of an error in the answers above, please click on this button before making any corrections 

Question # 7 (One answer) The height of the Coulomb-barrier decreases in the beginning when it is plotted as a function of the atomic number of the most stable target nucleus at each mass. The reason for this behavior is that

    A) the electrostatic repulsion doesn't work properly
    B) the law of conservation of charge is invalid
    C) the energy of the projectile becomes too small
    D) the projectile is heavier than the target nucleus
    E) the collision parameter becomes too large

Question # 8 (One answer) Rutherford's nuclear reaction is

    A) 2H+2H = 4He
    B) 2H + 3H = 4He + n
    C) 4He + 16O = 19Ne + n
    D) 4He + 14N = 17O + p
    E) 4He + 4He = 8Be

Question # 9 (One or more answers) The reaction energy for a typical nuclear reaction

    A) can be calculated from the change in total rest mass
    B) can be calculated from the change in mass number
    C) depends on the difference in spin between reactants and products
    D) can be positive
    E) can be negative

In case of an error in the answers above, please click on this button before making any corrections 

Question # 10 (One or more answers) In the treatment of transmutation reactions one can often assume that

    A) the Coulomb-barrier is never exceeded
    B) an intermediary compound nucleus is formed
    C) the law of constant mass action can be applied
    D) backscattering is negligible in the center of mass system
    E) the law of conservation of total energy is valid

In case of an error in the answers above, please click on this button before making any corrections 

Question # 11 (One answer) The mass energy is

    A) independent of the kinetic energy
    B) increasing with velocity
    C) independent of the total rest mass
    D) dependent on the square of the velocity
    E) small when the speed of light is reached

Question # 12 (One answer) When a projectile penetrates the Coulomb barrier the original kinetic energy is

    A) lost to the surroundings
    B) part of the reaction energy
    C) emitted at an angle of 45 degrees
    D) two times larger than the reaction energy
    E) remaining as kinetic energy of the center of mass

Question # 13 (One answer) The Coulomb barrier is

    A) the smallest distance that two nuclei can approach each other, rc
    B) the smallest kinetic energy that leads to a nuclear reaction between two colliding nuclei
    C) the kinetic projectile energy at which the Q-value changes its sign
    D) the electric force that prevents electrons from falling into the nucleus
    E) the external radius of an atomic nucleus

Question # 14 (One or more answers) Neutron multipliers normally uses a combination of

    A) 137Cs
    B) 208Pb
    C) 235U
    D) 252Cf
    E) 261Sg

In case of an error in the answers above, please click on this button before making any corrections 

Question # 15 (One answer) When a projectile approaches a nucleus, its energy increases again once it has passed the Coulomb barrier. This is caused by

    A) tunneling
    B) electrostatic attraction
    C) vacuum polarization
    D) the velocity
    E) the strong interaction force

Question # 16 (One answer) When using the conservation law for total energy of one must

    A) always neglect relativistic masses
    B) verify that the total charge really changes
    C) alway perform the calculations in the center of mass system
    D) include any relativistic mass increases as energy
    E) not forget to apply Avogadro's law

Question # 17 (One answer) The nuclear radius constant, ro, can have a numerical value which depends on how it is measured. What is the normal value of the Coulomb radius, rc?

    A) 1.0 fm
    B) 1.1 fm
    C) 1.2 fm
    D) 1.3 fm
    E) 1.4 fm

Question # 18 (One answer) The smallest projectile energy needed to start a nuclear reaction with a negative Q-value is called

    A) the roof energy
    B) the stair energy
    C) the threshold energy
    D) the floor energy
    E) the door energy

Question # 19 (One answer) Which of the following neutron sources has the highest yield of neutrons per Bq?

    A) 241Am+Be
    B) 210Po+Be
    C) 239Pu+Be
    D) 226Ra+Be
    E) 124Sb+Be

Question # 20 (One answer) The compound nucleus model predicts that for given numbers of neutrons and protons in the target+projectile combination

    A) one never gets the same products twice, regardless of the projectile+target combination tested
    B) the same products are obtained at a given reaction energy, independent of the possible choice of projectile+target
    C) only a certain combination of products can be obtained regardless of the energy used
    D) compound nucleus formation must be exoergic, or it will not take place
    E) the reaction fatilar is extreme at the capital point

Correct answers to each question can be obtained by clicking on the corresponding button below

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(Updated 2001-08-22)