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Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

Chapter 10 - Nuclear Physics

The release of atomic energyhas not created a newproblem. It has merely mademore urgent the necessity ofsolving an existing one.

-Albert Einstein

David J. StarlingPenn State Hazleton

PHYS 214

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

Ernest Rutherford proposed and discovered the

nucleus in 1911.

Alpha particles are positively charged helium nuclei 4He.

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

Ernest Rutherford proposed and discovered the

nucleus in 1911.

Alpha particles are positively charged helium nuclei 4He.

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

Their scattering angle theory matched

predictions!

Geiger and Marsden conducted the experiments with Radongas.

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

Their scattering angle theory matched

predictions!

Geiger and Marsden conducted the experiments with Radongas.

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

Protons (Z) and Neutrons (N) combine to give the

mass number (A) of the atom.

Note how the masses are not whole number multiples ofHydrogen.

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

Protons (Z) and Neutrons (N) combine to give the

mass number (A) of the atom.

Note how the masses are not whole number multiples ofHydrogen.

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

Atoms tend to have more neutrons than protons,

and can have multiple stable isotopes.

Bismuth (Z = 83) is the largest stable nucleus.

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

Atoms tend to have more neutrons than protons,

and can have multiple stable isotopes.

Bismuth (Z = 83) is the largest stable nucleus.

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

Stable nuclides have different abundances;

radionuclides have different half-lives.

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

The radius of nuclides can be roughly

approximated.

r = r0 A1/3

with r0 = 1.2 fm and A the mass number.

This only applies to spherical nuclides and not to unstablehalo nuclides (e.g., 113 Li).

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

The radius of nuclides can be roughly

approximated.

r = r0 A1/3

with r0 = 1.2 fm and A the mass number.

This only applies to spherical nuclides and not to unstablehalo nuclides (e.g., 113 Li).

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

Atomic masses are reported in atomic mass unitswith Carbon-12 defined to be 12 u.

1 u = 1.660538 1027 kg

mp = 1.672623 1027 kgmn = 1.674929 1027 kg

Therefore, the mass number of an atom and its atomic massare very similar (e.g., 197Au has a mass of 196.966522 u).

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

Atomic masses are reported in atomic mass unitswith Carbon-12 defined to be 12 u.

1 u = 1.660538 1027 kgmp = 1.672623 1027 kgmn = 1.674929 1027 kg

Therefore, the mass number of an atom and its atomic massare very similar (e.g., 197Au has a mass of 196.966522 u).

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

Atomic masses are reported in atomic mass unitswith Carbon-12 defined to be 12 u.

1 u = 1.660538 1027 kgmp = 1.672623 1027 kgmn = 1.674929 1027 kg

Therefore, the mass number of an atom and its atomic massare very similar (e.g., 197Au has a mass of 196.966522 u).

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

It takes energy to pull protons and neutrons apart;

therefore, they lose energy when they come

together.

This change in energy is equivalent to a change in mass (viaE = mc2).

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

It takes energy to pull protons and neutrons apart;

therefore, they lose energy when they come

together.

This change in energy is equivalent to a change in mass (viaE = mc2).

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

It takes energy to pull protons and neutrons apart;

therefore, they lose energy when they come

together.

This change in energy is equivalent to a change in mass (viaE = mc2).

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

The binding energy is just

Eb =

i

mic2 Mc2 > 0.

The mass excess is M A.

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

The binding energy is just

Eb =

i

mic2 Mc2 > 0.

The mass excess is M A.

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

The binding energy is just

Eb =

i

mic2 Mc2 > 0.

The mass excess is M A.

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

Once formed, nuclides have energy levels similar

to the electrons.

However, much more energy is required to excite thenucleus.

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

Once formed, nuclides have energy levels similar

to the electrons.

However, much more energy is required to excite thenucleus.

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

Once formed, nuclides have energy levels similar

to the electrons.

However, much more energy is required to excite thenucleus.

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

The Nucleus

Lecture Question 10.1Which statement is true about the forces inside an atom?

(a) Gravity holds electrons, while the strong nuclear forceholds nuclei together.

(b) Gravity holds electrons in their orbits and nucleitogether.

(c) Gravity holds electrons, while the electromagneticforce holds nuclei together.

(d) The strong nuclear force holds electrons, while theelectromagnetic force holds nuclei together.

(e) The electromagnetic force holds electrons, while thestrong nuclear force holds nuclei together.

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

Radioactive Decay

Unstable nuclei decay into other nuclei. For a

sample of N particles, the rate is proportional to

N with decay constant .

dNdt

= N

Solving for N:

dNN

= dt NN0

dNN

= t

0dt

lnNN0

= t

N = N0et

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

Radioactive Decay

Unstable nuclei decay into other nuclei. For a

sample of N particles, the rate is proportional to

N with decay constant .

dNdt

= N

Solving for N:

dNN

= dt

NN0

dNN

= t

0dt

lnNN0

= t

N = N0et

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

Radioactive Decay

Unstable nuclei decay into other nuclei. For a

sample of N particles, the rate is proportional to

N with decay constant .

dNdt

= N

Solving for N:

dNN

= dt NN0

dNN

= t

0dt

lnNN0

= t

N = N0et

Chapter 10 - NuclearPhysics

The Nucleus

Radioactive Decay

Nuclear Fission

Nuclear Fusion

Radioactive Decay

Unstable nuclei decay into other nuclei. For a

sample of N particles, the rate is proportional to

N with decay constant .

dNdt

= N

Solving for N:

dNN

= dt NN0

dNN

= t

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