The scientist who is credited with discovery of 'nucleus' in an atom is
Rutherford
Niels Bohr
Balmer
J J Thomson
The SI unit of radioactivity is
Rutherford
Roentgen
Becqueral
Curie
D.
Curie
The S.I unit ofradioactivity is Curie or disintegraton/sec.
1 Curie = 3.7 × 1010 dis/sec
In a sample of radioactive material, what percentage of the initial number of active nuclei will decay during one mean life ?
63 %
69.3 %
37 %
50 %