Deck 25: Energy From the Nucleus

Question 1

Consider the following energies:
1)minimum energy needed to excite a hydrogen atom
2)energy needed to ionize a hydrogen atom
3)energy released in ²³⁵U fission
4)energy needed to remove a neutron from a ¹²C nucleus
Rank them in order of increasing value.

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

Answer 1

1, 2, 4, 3

Question 2

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

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

Answer 2

less than before

Question 3

The binding energy per nucleon:

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

Answer 3

increases for all fission events

Question 4

The energy supplied by a thermal neutron in a fission event is essentially its:

A) excitation energy
B) binding energy
C) kinetic energy
D) rest energy
E) electric potential energy

Question 5

When ²³⁶U fissions the fragments are:

A) always ¹⁴⁰Xe and ⁹⁴Sr
B) always identical
C) never ¹⁴⁰Xe and ⁹⁴Sr
D) never identical
E) none of the above

Question 6

Fission fragments usually decay by emitting:

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

Question 7

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

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 8

The barrier to fission comes about because the fragments:

A) attract each other via the strong nuclear force
B) repel each other electrically
C) produce magnetic fields
D) have large masses
E) attract electrons electrically

Question 9

The binding energy per nucleon:

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 10

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

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 11

Which one of the following represents a fusion reaction that would yield large amounts of energy?

A) ²³⁸U₉₂ + ¹n₀ $\rightarrow$ ⁹⁰Kr₃₆ + ¹⁴⁶Cs₅₅ + ²H₁ + ¹n₀
B) ²³⁹Pu₉₂ + 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 12

The barrier to fusion comes about because protons:

A) attract each other via the strong nuclear force
B) repel each other electrically
C) produce magnetic fields
D) attract neutrons via the strong nuclear force
E) attract electrons electrically

Question 13

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

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

Question 14

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

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

Question 15

Nuclear fusion in the Sun is increasing its supply of:

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

Question 16

The energy released in a complete proton-proton cycle is about:

A) 3 keV
B) 30 keV
C) 3 MeV
D) 30 MeV
E) 300 MeV

Question 17

Tokamaks confine deuteron plasmas using:

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

Question 18

Most magnetic confinement projects attempt:

A) proton-proton fusion
B) proton-deuteron fusion
C) deuteron-deuteron fusion
D) deuteron-triton fusion
E) triton-triton fusion

Question 19

Compared to fusion in a tokamak, laser fusion makes use of:

A) smaller particle number densities
B) greater particle number densities
C) longer confinement times
D) higher temperatures
E) lower temperatures

Question 20

Most laser fusion projects attempt:

A) proton-proton fusion
B) proton-deuteron fusion
C) deuteron-deuteron fusion
D) deuteron-triton fusion
E) triton-triton fusion