PH 202-5E Fall 2005
Nuclear physics and radioactivity
Lecture 39-43
Chapter 31
(Cutnell & Johnson, Physics 6th edition)
1
Nuclear Physics
7.2x10-15 m
The nucleus of the aluminum
atom, consisting of 13 protons
and 14 neutrons
2
Isotopes
Some of the isotopes of carbon
Atoms with the same number of protons in their nuclei,
but different number of neutrons are called isotopes
Most of the isotopes are unstable, they decay and
transmute into another element
3
4
5
6
7
The strong force and the nuclear binding energy
•The strong force acts equally between any two nucleons,
regardless of whether they are protons or neutrons
•The strong force has a short range
8
9
A plot of the number of neutrons vs the number of protons
(N vs Z)
10
Binding energy
+
+
Binding
Energy
+
+
+
+
11
Average Binding Energy per Nucleon vs. Mass Number
12
13
14
15
Transmutation of Elements
16
17
Radioactivity
18
Alpha Decay
238U→234Th
+α
19
Beta Decay
60
27
Co →
60
27 +1
_
Ni + e + ν ( antineutri no )
0 −
−1
20
β-decay reactions involving the conversion of a
proton into a neutron and the ejection of an antielectron (positron) and a neutrino
21
22
23
The law of radioactive decay
24
25
26
27
28
29
Nuclear bomb and nuclear reactors
Hydrogen (H) bomb
Hydrogen
30
Nuclear reactor
31
32
33
Fusion
34
35