Atomic weight of boron is 10.81 and it has two isotopes and . Then, the ratio of atoms of and in nature would be
19 : 81
10 : 11
15 : 16
81 : 19
Which of the following is used as a moderator in nuclear reactors?
Plutonium
Cadmium
Heavy water
Uranium
The stable nucleus that has a radius half that of Fe56 is
Li7
Na21
S16
Ca40
Heavy water is used as a moderator in a nuclear reactor. The function of the moderator is
to control energy released in the reactor
to absorb neutrons and stop chain reaction
to cool the reactor
to slow down the neutrons to thermal energies
What is the radius of iodine atom? (Atomic No.53, Mass No. 126)
2.5 x 10-11 m
2.5 x 10-9 m
7 x 10-9 m
7 x 10-6 m
In a fission reaction
the binding energy per nucleon of X and Y is 8.5 MeV whereas of 236U is 7.6 MeV. The total energy liberated will be about
2000 MeV
200 MeV
2 MeV
1 keV
A free neutrons decays into a proton, an electron and
a beta particle
an alpha particle
an antineutrino
an neutrino
A nucleus ruptures into two nuclear parts, which have their velocity ratio equal to 2 :1. What will be the ratio of their nuclear size (nuclear radius)?
21/3 : 1
1 : 21/3
31/2 : 1
1 : 31/2
The mass number of He is 4 and that for sulphur is 32. The radius of sulphur nuclei is larger than that of helium by
√8
4
2
8
The average binding energy of a nucleon inside an atomic nucleus is about
8 MeV
8 eV
8 J
8 erg