6.Radioactive disintegration differs from a chemical change in being

7.The half-life period of radioactive element is 140 days. After 560 days, one gram of the element will reduce to

8.The tremendous amount of energy released during explosion of a hydrogen bomb is due to

9.The masses of neutron and proton are 1.0087 and 1.0073 amu respectively. If the neutrons and proton combine to form helium nucleus of mass 4.0015 amu, the binding energy of helium nucleus would be

10.All nuclides exhibit radioactivity when the atomic number exceeds