March 07, 2012

Nuclear Chemistry One Mark Questions

1. 92U235 Nucleus absorbs a neutron and disintegrates into 54Xe139, 38Sr94 and X. What is X?
a) 3 neutrons         b) 2 neutrons               c) α – particle              d) β – particle.
2. After 24 hours 0.125 g of the initial quantity of 1 g of a radioactive isotope is left out / is left out. The half-life period is
a) 24 hours            b) 12 hours                  c) 8 hours                    d) 16 hours /
a) 0.8 hours           b) 8 hours                     c) 100 hours               d) 80 hours
3. Find out the missing: In a reaction 5B84Be8 +?
a) α-particle           b) β -particle                c) electron capture       d) positron.
4. Half life period of a radioactive element is 1500 years. Find the value of disintegration constant in terms of second.
a) 0.1465 × 10-10 sec–1                            b) 0.2465 × 10-10 sec–1
c) 0.1465 × 10-8 sec–1                              d) 0.3645 × 10-10 sec–1
5. Half-life period of a radioactive element is 100 seconds. Its average life period is
a) 100 seconds      b) 50 seconds              c) 200 seconds            d) 144 seconds.
6. In nuclear reaction --------- is / are balanced on both sides.
a) mass                                                      b) number of atoms
c) mass number                                         d) atomic number and mass number
7. Loss of β – particle is equivalent to
a) increase of one proton only                               b) decrease of one neutron
c) loss of proton /  increase of one neutron only / none of these d) both (a) and (b).
8. Radioactivity is due to
a) Stable electronic configuration             b) Stable nucleus
c) Unstable nucleus                                   d) Unstable electronic configuration.
9. The isotope of which element is used in nuclear fission reaction?
a) Barium              b) Lead                        c) Uranium                  d) Caesium.
10. The most penetrating radiations are
a) α rays                 b) β rays                      c) γ rays                       d) all are equally penetrating
11. The reaction 5B84Be8 takes place due to
a) α -decay            b) β-decay                   c) electron capture       d) positron decay.
12. When 7N15 is bombarded with a proton it gives 6C12 and
a) α- particle          b) β- particle                c) neutron                    d) proton
13. Which of the following is used as neutron absorber in nuclear reactors?
a) Water                b) Deuterium               c) Uranium                  d) Cadmium
14. Which one of the following particles is used to bombard 13Al27 to give 15P30 and a neutron?
a) α-particle           b) Deuteron / β-particle           c) Proton         d) Neutron.