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CBSE NOTES CLASS 12 PHYSICS

CHAPTER 13 NUCLEUS

Subatomic particles

Nucleus

Nucleons

Atomic mass unit

Mass energy

Mass defect

Nuclear force

Nuclear binding energy

Binding energy per nucleon

Properties of binding force and binding energy

Relation of nuclear size and atomic mass number

Nuclear density

Isotopes

Isobars

Isotones

Isomers

Radioactivity

α-rays

β-rays

γ-rays

Law of radioactive decay

Rate of decay of nucleus

Half-life of a radioactive element

Average life or mean life of a radioactive element (τ)

Nuclear fission

Structure of nuclear reactor

Nuclear fuel

Moderator

Control rods

Coolant in nuclear reactor

Pressure vessel or pressure tubes in nuclear reactor

Steam generator in nuclear reactor

Nuclear fusion

The proton-proton (p, p) cycle in the sun

CBSE NOTES CLASS 12 PHYSICS

CHAPTER 13 NUCLEUS

Nucleus

Rutherford proposed that the entire positive charge and nearly the entire mass of atom are concentrated in a very small space called the nucleus of an atom.

The nucleus consists of protons and neutrons. They are called nucleons.

Z - atomic number = number of protons

N - neutron number = number of neutrons

A - mass number = Z + N = total number of protons and neutrons

Nuclear species or nuclides are shown by the notation XZA where X is the chemical symbol of the species. For example, the nucleus of gold is denoted byAu79 197. It contains 197 nucleons, of which 79 are protons and the rest 118 are neutrons.

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