PGTRB:LATEST STUDY MATERIALS: PHYSICS: NUCLEAR PHYSICS. - Tamil Crowd (Health Care)

PGTRB:LATEST STUDY MATERIALS: PHYSICS: NUCLEAR PHYSICS.

 PGTRB:LATEST STUDY MATERIALS: 

PHYSICS: 
NUCLEAR PHYSICS.

  • Neutrons and protons are present in the nucleus. It is charged positively.
  • Isotopes are the atoms of the same element having the same number of protons but different number of neutrons.
  • The higher the binding energy per nucleon the more stable is the nucleus. 
  • Neutrons and protons are collectively called nucleons.
  • The unit of radiation is Roentgen.
  • In natural radio activity only Alpha, Beta, and Gamma rays are emitted.
  • But in artificial radio activity particles like electrons, neutrons, positrons and Gamma rays are liberated.
  • Radio isotopes have a wide application in the field of Agriculture, Medicine and Biology.
  • Cyclotron is one of the accelerators to accelerate charged particles.
  • To compare the radio activities of elements, the half life period and mean carbon dating.
  • Neutron was discovered by Chadwick.
  • The neutrons are neutral particles. They cannot be deflected by electric or magnetic field.
  • Slow neutrons are called thermal neutrons and are used in fission reaction.
  • Nuclear forces are the enormous forces so far discovered.
  • The working principle of atom bomb is nuclear fission.
  • The working principle of hydrogen bomb is nuclear fusion.
  • The hydrogen isotopes are involved in nuclear fusion reaction in hydrogen bomb. hence the name hydrogen bomb.
  • Fusion requires a high temperature whereas fission takes place at normal temperature.
  • Nuclear fusion takes place in sun and stars because high temperature are available there.
  • Uncontrolled chain reaction takes place in Atom whereas controlled chain reaction takes place in nuclear reactor.
  • In a hydrogen bomb Uncontrolled nuclear fusion reaction takes place.
  • Cosmic rays are ionizing radiations showering on earth all the time coming from outer space.
  • The intensity of cosmic rays will changed both with altitude and latitude.
  • The process in which a particle and its antiparticle combine to yield new particle is called annihilation of matter.
  • Photons, leptons, mesons, baryons and hyperons and neutrino are the various group of elementary particle.
  • Energy equivalence to 1 amu is 931 Mev.
  • BE/A curve shows that iron nucleus is stable.
  • Cobalt 60 is used for the treatment of cancer.
  • Atomic number is increased by one in Beta decay.
  • To evaluate the ages of ancient object the following method is adopted Radio carbon dating.
  • One of the particle accelerator Cyclotron 
  • Neutrons are neutral particles.
  • Neutrons with energies between 0.5 MeV to 10 MeV are called fast neutrons.
  • To control the chain reaction the following rods are used in a nuclear reactor cadmium rods.
  • In pair production the following pairs are formed electrons and positrons.
  • A nuclear reactor is a device in which the nuclear reaction is carried on as perfectly controlled chain reaction in a self sub stained manner.
  • The fissionable material or the nuclear fuel is generally 92U235. In some reactors Plutonium-239 is also used.
  • Materials like cadmium or Boron are very good absorbers of neutron and are used o control the chain reactions.
  • A material used to absorb the heat generated in chain reactions is a coolant.
  • In nuclear reactors energy set free is in the form of heat which could be converted into electrical energy.
  • The cyclotron can accelerate protons, deutrons, and alpha-particles.
  • The property of radiations to ionise the gas through which they pass is used in the Geiger counter.
  • The spiral type of accelerator called cyclotron was first developed by Lawrence in 1930.
  • carbon -14 provides a radioactive clock for anthropologists. This is called radio carbon dating.
  • The curve rises sharply at first and then more gradually until it reaches maximum of 8.8 MeV.
  • The average binding energy is 8.5 MeV for moderate nuclei having the mass number range from 40 to 120.
  • The binding energy per nucleon = 5.4 MeV.

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