DIRECTION: Each of these question contains two statements: Statement-1 (Assertion) and Statement-2(Reason). Answer these questions from the following fouroptions.

Statement- 1 :The ionising power of β-particle is less compared to α-particles but their penetrating power is more.

Statement- 2 :The mass of β-particle is less than the mass of α-particle.

DIRECTION: Each of these question contains two statements: Statement-1 (Assertion) and Statement-2(Reason). Answer these questions from the following fouroptions.

Statement- 1 :Radioactivity of 10⁸ undecayed radioactive nuclei of half life of 50 days is equal to that of 1.2 × 10⁸ number of undecayed nuclei of some other material with half life of 60 days.

Statement- 2 :Radioactivity is proportional to half-life.

DIRECTION: Each of these question contains two statements: Statement-1 (Assertion) and Statement-2(Reason). Answer these questions from the following fouroptions.

Statement- 1: The binding energy per nucleon, for nuclei with atomic mass number A >100, decrease with A.

Statement- 2 : The forces are weak for heavier nuclei.

Activity of a radioactive sample decreases to (1/3) rd of its original value in 3 days. Then, in 9 days its activity will become

Fraction of tritium left after 150 years (half life of tritium is 12.5 years) is

The half life of a radioactive isotope ‘X’ is 20 years. It decays to another element ‘Y’ which is stable. The two elements‘X’ and ‘Y’ were found to be in the ratio of 1: 7 in a sample of a the given rock. The age of the rock is estimated to be

A certain mass of Hydrogen is changed to Helium by the process of fusion. The mass defect in fusion reaction is 0.02866 a.m.u. The energy liberated per a.m.u. is(Given : 1 a.m.u = 931 MeV)

A mixture consists of two radioactive materials A₁ and A₂ with half lives of 20 s and 10 s respectively. Initially the mixture has 40 g of A₁ and 160 g of A₂. The amount of the two in the mixture will become equal after