A radioactive nucleus (initial mass number A and atomic number Z) emits 3α- particles and 2 positrons. The ratio of number of neutrons to that of protons in the final nucleus will be :
Which of the following is used as a moderator in nuclear reactors?
Plutonium
Cadmium
Heavy water
Uranium
The binding energy of deuteron is 2.2 MeV and that of is 28 MeV. If two deuterons are fused to from one , then the energy released is
25.8 MeV
23.6 MeV
19.2 MeV
30.2 MeV
The nucleus 6C12 absorbs an energetic neutron and emits a beta particle ( β ). The resulting nucleus is
7N14
7N13
5B13
6C13
The average binding energy of a nucleon inside an atomic nucleus is about
8 MeV
8 eV
8 J
8 erg
The radioactive decay of uranium in the thorium is represented by the equation:
92U238 → 90Th234 + x
What is x ?
An α-particle
An electron
A proton
a neutron
If the binding energy per nucleon in 3Li7 and 2He4 nuclei are respectively 5.60 MeV and 7.06 MeV, then the energy of proton in the reaction 3Li7+ p → 2 2He4 is
19.6 MeV
2.4 MeV
8.4 MeV
17.3 MeV
A radioactive element has half-life period 800 yr. After 6400 yr what amount will remain?
1/2
1/16
1/8
1/256
The ratio of the radii of the nuclei 13Al27 and 52Te125 is approximately
6 :10
13 : 52
40 : 177
14 : 73
Which of the following statements is true for nuclear forces?
They obey the inverse square law of distance.
They obey the inverse third power law of distance.
They are short range forces.
They are equal in strength to electromagnetic forces.
