Question 1

In a neutron-induced fission process, delayed neutrons come from:

Accepted Answer

A)  the fission products 
B)  the original nucleus just before it absorbs the neutron 
C)  the original nucleus just after it absorbs the neutron 
D)  the moderator material 
E)  the control rods 
A)  the fission products 
B)  the original nucleus just before it absorbs the neutron 
C)  the original nucleus just after it absorbs the neutron 
D)  the moderator material 
E)  the control rods A

Question 2

235U is readily made fissionable by a thermal neutron but 238U is not because:

Accepted Answer

A)  the neutron has a smaller binding energy in 236U 
B)  the neutron has a smaller excitation energy in 236U 
C)  the potential barrier for the fragments is less in 239U 
D)  the neutron binding energy is greater than the barrier height for 236U and less than the barrier height for 239U 
E)  the neutron binding energy is less than the barrier height for 236U and greater than the barrier height for 239U 
A)  the neutron has a smaller binding energy in 236U 
B)  the neutron has a smaller excitation energy in 236U 
C)  the potential barrier for the fragments is less in 239U 
D)  the neutron binding energy is greater than the barrier height for 236U and less than the barrier height for 239U 
E)  the neutron binding energy is less than the barrier height for 236U and greater than the barrier height for 239U D

Question 3

If the nucleus of a lead atom were broken into two identical nuclei, the total mass of the result would be:

Accepted Answer

A)  the same as before 
B)  greater than before 
C)  less than before 
D)  converted into radiation 
E)  converted into kinetic energy 
A)  the same as before 
B)  greater than before 
C)  less than before 
D)  converted into radiation 
E)  converted into kinetic energy C

Question 4

The first step of the proton-proton cycle is:

Accepted Answer

A)  1H + 1H $\rightarrow$2H 
B)  1H + 1H $\rightarrow$ 2H + e+ + $\nu$ 
C)  1H + 1H $\rightarrow$2H + e- + $\nu$ 
D)  1H + 1H $\rightarrow$2H + $\gamma$ 
E)  1H + 1H $\rightarrow$3H + e- + $\nu$ 
A)  1H + 1H $\rightarrow$2H 
B)  1H + 1H $\rightarrow$ 2H + e+ + $\nu$ 
C)  1H + 1H $\rightarrow$2H + e- + $\nu$ 
D)  1H + 1H $\rightarrow$2H + $\gamma$ 
E)  1H + 1H $\rightarrow$3H + e- + $\nu$

Question 5

Lawson's number is 1020 s .m-3. If the density of deuteron nuclei is 2 * 1021 m-3 what should the confinement time be to achieve sustained fusion?

Accepted Answer

A)  16 ms 
B)  50 ms 
C)  160 ms 
D)  250 ms 
E)  500 ms 
A)  16 ms 
B)  50 ms 
C)  160 ms 
D)  250 ms 
E)  500 ms

Question 6

The binding energy per nucleon:

Accepted Answer

A)  increases from all fusion events 
B)  increases for some, but not all, fusion events 
C)  remains the same for some fusion events 
D)  decreases for all fusion events 
E)  decreases for some, but not all, fusion events 
A)  increases from all fusion events 
B)  increases for some, but not all, fusion events 
C)  remains the same for some fusion events 
D)  decreases for all fusion events 
E)  decreases for some, but not all, fusion events

Question 7

In a nuclear reactor the fissionable fuel is formed into pellets rather than finely ground and mixed with the moderator. This reduces the probability of:

Accepted Answer

A)  non-fissioning absorption of neutrons 
B)  loss of neutrons through the reactor container 
C)  absorption of two neutrons by single fissionable nucleus 
D)  loss of neutrons in the control rods 
E)  none of the above 
A)  non-fissioning absorption of neutrons 
B)  loss of neutrons through the reactor container 
C)  absorption of two neutrons by single fissionable nucleus 
D)  loss of neutrons in the control rods 
E)  none of the above

Question 8

Nuclear fusion in the Sun is increasing its supply of:

Accepted Answer

A)  hydrogen 
B)  helium 
C)  nucleons 
D)  positrons 
E)  neutrons 
A)  hydrogen 
B)  helium 
C)  nucleons 
D)  positrons 
E)  neutrons

Question 9

In the uranium disintegration series:

Accepted Answer

A)  the emission of a $\beta$- particle increases the mass number A by one and decreases the atomic number Z by one 
B)  the disintegrating element merely ejects atomic electrons 
C)  the emission of an $\alpha$particle decreases the mass number A by four and decreases the atomic number Z by two 
D)  the nucleus always remains unaffected 
E)  the series of disintegrations continues until an element having eight outermost orbital electrons is obtained 
A)  the emission of a $\beta$- particle increases the mass number A by one and decreases the atomic number Z by one 
B)  the disintegrating element merely ejects atomic electrons 
C)  the emission of an $\alpha$particle decreases the mass number A by four and decreases the atomic number Z by two 
D)  the nucleus always remains unaffected 
E)  the series of disintegrations continues until an element having eight outermost orbital electrons is obtained

Question 10

Consider the following energies:   Rank them in order of increasing value.

Accepted Answer

A)  1, 2, 3, 4 
B)  1, 3, 2, 4 
C)  1, 2, 4, 3 
D)  2, 1, 4, 3 
E)  2, 4, 1, 3 
A)  1, 2, 3, 4 
B)  1, 3, 2, 4 
C)  1, 2, 4, 3 
D)  2, 1, 4, 3 
E)  2, 4, 1, 3

Question 11

Nuclear fusion in stars produce all the chemical elements with mass numbers less than:

Accepted Answer

A)  56 
B)  66 
C)  70 
D)  82 
E)  92 
A)  56 
B)  66 
C)  70 
D)  82 
E)  92

Question 12

Most of the energy produced by the Sun is due to:

Accepted Answer

A)  nuclear fission 
B)  nuclear fusion 
C)  chemical reaction 
D)  gravitational collapse 
E)  induced emf's associated with the Sun's magnetic field 
A)  nuclear fission 
B)  nuclear fusion 
C)  chemical reaction 
D)  gravitational collapse 
E)  induced emf's associated with the Sun's magnetic field

Question 13

Tokamaks confine deuteron plasmas using:

Accepted Answer

A)  thick steel walls 
B)  magnetic fields 
C)  laser beams 
D)  vacuum tubes 
E)  electric fields 
A)  thick steel walls 
B)  magnetic fields 
C)  laser beams 
D)  vacuum tubes 
E)  electric fields

Question 14

Which one of the following represents a fission reaction that can be activated by slow neutrons?

Accepted Answer

A)  (238U92 + 1n0 $\rightarrow$90Kr36 + 146Cs55 + 2H1 + 1n0) 
B)  (239Pu94 + 1n0 $\rightarrow$96Sr38 + 141Ba56 + 31n0) 
C)  (238U92 $\rightarrow$234Th90 + 4He2) 
D)  (3H1 + 2H1$\rightarrow$4He2 + 1n0) 
E)  (107Ag47 + 1n0$\rightarrow$108Ag47 $\rightarrow$ 108Cd48 + 0e-1) 
A)  (238U92 + 1n0 $\rightarrow$90Kr36 + 146Cs55 + 2H1 + 1n0) 
B)  (239Pu94 + 1n0 $\rightarrow$96Sr38 + 141Ba56 + 31n0) 
C)  (238U92 $\rightarrow$234Th90 + 4He2) 
D)  (3H1 + 2H1$\rightarrow$4He2 + 1n0) 
E)  (107Ag47 + 1n0$\rightarrow$108Ag47 $\rightarrow$ 108Cd48 + 0e-1)

Question 15

Separation of the isotopes of uranium requires a physical, rather than chemical, method because:

Accepted Answer

A)  mixing other chemicals with uranium is too dangerous 
B)  the isotopes are chemically the same 
C)  the isotopes have exactly the same number of neutrons per nucleus 
D)  natural uranium contains only 0.7% 235U 
E)  uranium is the heaviest element in nature 
A)  mixing other chemicals with uranium is too dangerous 
B)  the isotopes are chemically the same 
C)  the isotopes have exactly the same number of neutrons per nucleus 
D)  natural uranium contains only 0.7% 235U 
E)  uranium is the heaviest element in nature

Question 16

When uranium undergoes fission as a result of neutron bombardment, the energy released is due to:

Accepted Answer

A)  oxidation of the uranium 
B)  kinetic energy of the bombarding neutrons 
C)  radioactivity of the uranium nucleus 
D)  radioactivity of the fission products 
E)  a reduction in binding energy 
A)  oxidation of the uranium 
B)  kinetic energy of the bombarding neutrons 
C)  radioactivity of the uranium nucleus 
D)  radioactivity of the fission products 
E)  a reduction in binding energy

Question 17

The purpose of a moderator in a nuclear reactor is to:

Accepted Answer

A)  provide neutrons for the fission process 
B)  slow down fast neutrons to increase the probability of capture by uranium 
C)  absorb dangerous gamma radiation 
D)  shield the reactor operator from dangerous radiation 
E)  none of the above 
A)  provide neutrons for the fission process 
B)  slow down fast neutrons to increase the probability of capture by uranium 
C)  absorb dangerous gamma radiation 
D)  shield the reactor operator from dangerous radiation 
E)  none of the above

Question 18

To produce energy by fusion of two nuclei, the nuclei must:

Accepted Answer

A)  have at least several thousand electron volts of kinetic energy 
B)  both be above iron in mass number 
C)  have more neutrons than protons 
D)  be unstable 
E)  be magic number nuclei 
A)  have at least several thousand electron volts of kinetic energy 
B)  both be above iron in mass number 
C)  have more neutrons than protons 
D)  be unstable 
E)  be magic number nuclei

Question 19

Fission fragments usually decay by emitting:

Accepted Answer

A)  alpha particles 
B)  electrons and neutrinos 
C)  positrons and neutrinos 
D)  only neutrons 
E)  only electrons 
A)  alpha particles 
B)  electrons and neutrinos 
C)  positrons and neutrinos 
D)  only neutrons 
E)  only electrons

Question 20

When 236U fissions, the products might be:

Accepted Answer

A)  (146Ba, 89Kr,) and a proton 
B)  (146Ba, 89Kr,) and a neutron 
C)  (148Cs and 85Br) 
D)  (133I, 92Sr,) and an alpha particle 
E)  two uranium nuclei 
A)  (146Ba, 89Kr,) and a proton 
B)  (146Ba, 89Kr,) and a neutron 
C)  (148Cs and 85Br) 
D)  (133I, 92Sr,) and an alpha particle 
E)  two uranium nuclei

Exam 43: Energy From the Nucleus

In a neutron-induced fission process, delayed neutrons come from:

235U is readily made fissionable by a thermal neutron but 238U is not because:

If the nucleus of a lead atom were broken into two identical nuclei, the total mass of the result would be:

The first step of the proton-proton cycle is:

Lawson's number is 1020 s .m-3. If the density of deuteron nuclei is 2 * 1021 m-3 what should the confinement time be to achieve sustained fusion?

The binding energy per nucleon:

In a nuclear reactor the fissionable fuel is formed into pellets rather than finely ground and mixed with the moderator. This reduces the probability of:

Nuclear fusion in the Sun is increasing its supply of:

In the uranium disintegration series:

Consider the following energies: Rank them in order of increasing value.

Nuclear fusion in stars produce all the chemical elements with mass numbers less than:

Most of the energy produced by the Sun is due to:

Tokamaks confine deuteron plasmas using:

Which one of the following represents a fission reaction that can be activated by slow neutrons?

Separation of the isotopes of uranium requires a physical, rather than chemical, method because:

When uranium undergoes fission as a result of neutron bombardment, the energy released is due to:

The purpose of a moderator in a nuclear reactor is to:

To produce energy by fusion of two nuclei, the nuclei must:

Fission fragments usually decay by emitting:

When 236U fissions, the products might be:

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Filters

²³⁵U is readily made fissionable by a thermal neutron but ²³⁸U is not because:

Lawson's number is 10²⁰ s .m^-³. If the density of deuteron nuclei is 2 * 10²¹ m^-³ what should the confinement time be to achieve sustained fusion?

When ²³⁶U fissions, the products might be: