Nuclear fission was discovered by
A piece of wood from the ruins of an ancient building was found to have a C14 activity of 12 disintegration per minute per gram of its carbon content. The C14 activity of the living wood is 16 disintegration per minute per gram. How long ago did the tree, from which the wooden sample came, di? Given half-life of C14 is 5760 years.
The rest mass of an electron as well so that of positron is 0.51 cMeV. When an electron and positron are annihilate they produce gamma-rays of wavelength(s)
A heavy nucleus having mass number 200 gets disintegrated into two small fragments of mass number 80 and 120. If binding energy per nucleon for parent atom is 6.5 MeV and for daughter nuclei is 7 MeV and 8 MeV respectively, then the energy released in the decay will be -
Consider α particles, β particles and γ - rays, each having an energy of 0.5 MeV. In increasing order of penetrating powers, the radiations are:
The half life of a radioactive substance is 20 minutes. The approximate time interval (t2−t1)between the time t2 when 23 of it had decayed and time t1 when 13 of it had decayed is: