Review:
a) Energy is the capacity to do work.
b) Energy exists in different forms.
c) SI unit of work is joule.
d) Energy can be transformed from one form to another.
e) An isotope of an element X is represented by the symbol ZXA or AZX where Z is the atomic number and A is the mass number.
INTRODUCTION
Some isotopes are radioactive while others are not . Those which are not radioactive are stable while those which are radioactive are unstable.
Note:
The question arises as to why some isotopes are unstable.
The nucleons in a nucleus are bound together by forces called nuclear forces. Energy is required to separate the nucleons. The minimum energy required for the purpose is called binding energy. Stability is usually measured by binding energy per nucleon
[be per nucleon = (binding energy / mass numebr)]. Higher the binding energy per nucleon. greater the stability of the nucleus.
According to Einstein, mass and energy are interconvertible. The total of mass and energy is conserved. This is known as Einstein’s mass-energy relation. If a mass DM (The symbol D is used to indicate small quantity) is completely converted into energy DE, than
This is the basis on which energy released in a nuclear reaction may be explained.
a) Energy is the capacity to do work.
b) Energy exists in different forms.
c) SI unit of work is joule.
d) Energy can be transformed from one form to another.
e) An isotope of an element X is represented by the symbol ZXA or AZX where Z is the atomic number and A is the mass number.
INTRODUCTION
Some isotopes are radioactive while others are not . Those which are not radioactive are stable while those which are radioactive are unstable.
Note:
The question arises as to why some isotopes are unstable.
The nucleons in a nucleus are bound together by forces called nuclear forces. Energy is required to separate the nucleons. The minimum energy required for the purpose is called binding energy. Stability is usually measured by binding energy per nucleon
[be per nucleon = (binding energy / mass numebr)]. Higher the binding energy per nucleon. greater the stability of the nucleus.
MEANING OF NUCLEAR ENERGY
Nuclear reaction
Transmutation of a nucleus and reaction between two nuclei are examples for nuclear reaction. It is totally different from a chemical reaction which involves only orbital electrons. Electrons have no role in nuclear reactions. A nuclear reaction is exothermic where as chemical reactions may be exothermic or endothermic.
Note:
Accurate measurements of nuclear masses using precision instruments such as mass spectrographs have shown that the mass of a nucleus is lesser than the sum of the masses of the constituent particles. The mass difference called Mass defect corresponds to binding energy.
Where does the nuclear energy come from ?
During a nuclear reaction, the sum of the masses of the product (or resultant) particles is lesser than the sum of the masses reactant particles. This difference in mass is converted into energy. The conversion that takes place can be explained by Einstein’s mass-energy relation.
Any reaction that involves a change in the nucleus of an atom is called a nuclear reaction. The energy released during a nuclear reaction is called nuclear energy. This is sometimes called atomic energy.
Nuclear reaction
Transmutation of a nucleus and reaction between two nuclei are examples for nuclear reaction. It is totally different from a chemical reaction which involves only orbital electrons. Electrons have no role in nuclear reactions. A nuclear reaction is exothermic where as chemical reactions may be exothermic or endothermic.
Note:
Accurate measurements of nuclear masses using precision instruments such as mass spectrographs have shown that the mass of a nucleus is lesser than the sum of the masses of the constituent particles. The mass difference called Mass defect corresponds to binding energy.
Where does the nuclear energy come from ?
DE = Mc2.
where c = velocity of light.
For example, if DM = 1 mg
= 10-6 kg then DE =10-6(3x108)2
= 9
*1010 J.
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