Nuclei

The scientist who is credited with discovery of 'nucleus' in an atom is

• Rutherford

• Niels Bohr

• Balmer

• J J Thomson

In nuclear fission the percentage of mass converted into energy is about

• 0.01 %

• 10 %

• 1 %

• 0.1 %

The SI unit of radioactivity is

• Rutherford

• Roentgen

• Becqueral

• Curie

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 %