A radioactive element has half-life period 800 yr. After 6400 yr what amount will remain?
1/2
1/16
1/8
1/256
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
Energy released in the fission of a single 92U235 nucleus is 200 MeV. The fission rate of a 92U235 filled reactor operating at a power level of 5 W is
1. 56 × 10-10 s -1
1. 56 × 1011 s-1
1. 56 × 10-16 s-1
1. 56 × 10 -17 s-1
The constituents of atomic nuclei are believed to be
neutrons and protons
protons only
electrons and protons
electrons, protons and neutrons
The mass density of a nucleus varies with mass number A as
A2
A
constant
1/A
Solar energy is due to
fusion reaction
fission reaction
combustion reaction
chemical reaction
The energy equivalent of one atomic mass unit is:
1.6 × 10-19 J
6.02 × 1023J
931 MeV
9.31 MeV
Curie is a unit of
energy of gamma rays
half - life
radioactivity
intensity of gamma rays
The nucleus 48Cd115, after two successive β-decay will give
46Pa115
49In114
50Sn113
50Sn115
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.
