CBSE
Short Answer TypeA radioactive isotope X with half life 1.5x 109 yr decays into a stable nucleus Y. A rock sample contains both elements X and Y in ratio 1 : 15. Find the age of the rock.
Multiple Choice QuestionsThe energy released by the fission of one uranium atom is 200 MeV. The number of fissions per second required to produce 3.2 W of power is (Take, 1eV = 1.6 x 10-19 J)
107
1010
1015
1011
In the nuclear reaction , the X will be
A radioactive nucleus of mass number A, initially at rest, emits an α-particle with a speed v. The recoil speed of the daughter nucleus will be
What is the particle X in the following nuclear reaction ?
Electron
Proton
Photon
Neutron
A certain mass of hydrogen is changed to helium by the process of fusion. The mass defect in fusion reaction is 0.02866 u. The energy liberated per u is (given 1 u = 931 MeV)
2.67 MeV
26.7 MeV
6.675 MeV
13.35 MeV
Two radioactive substances A and B have decay constants 5 λ and λ respectively. At t = 0, they have the same number of nuclei. The ratio of number of nuclei of A to that of B will be (1/e)2 after a time interval of
Short Answer TypeAt time t = O, a radioactive sample has a mass of 10 g. Calculate the expected mass of radioactive sample after two successive mean lives.
Multiple Choice QuestionsFor the radioactive nuclei that undergo either α or β decay, which one of the following cannot occur ?
Isobar of original nucleus is produced
Isotope of the original nucleus is produced
Nuclei with higher atomic number than that of the original nucleus is produced
Nuclei with lower atomic number than that of the original nucleus is produced
The half-life of a radioactive isotope X is 20 yr. It decays to another element Y which is stable. The two elements X and Y were found to be in the ratio 1 : 7 in a sample of a given rock. The age of the rock is estimated to be
40 yr
60 yr
80 yr
100 yr
