The nuclei 6C13 and 7N14 can be described as
isotones
isobars
isotopes of carbon
isotopes of nitrogen
The constituents of atomic nuclei are believed to be
neutrons and protons
protons only
electrons and protons
electrons, protons and neutrons
Half-lives of two radioactive substances A and B are respectively 20 min and 40 min. Initially the samples of A and B have equal number of nuclei. After 80 min the ratio of remaining number of A and B nuclei is
1 : 16
4 : 1
1 : 4
1 : 1
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
In a given reaction
ZXA → Z+1YA → Z-1KA-4 → Z-1KA-4
Radioactive radiations are emitted in the sequence of
α, β, γ
γ, α, β
β, α, γ
γ, β, α
The average binding energy of a nucleon inside an atomic nucleus is about
8 MeV
8 eV
8 J
8 erg
The activity of a radioactive sample is measured as 9750 counts/min at t = 0 and as 975 counts/min at t = 5 min. The decay constant is approximately
0.922/min
0.691/min
0.461/min
0.230/min
A radioactive sample with a half-life of 1 month has the label : 'Activity = 2 microcurie on 1-8-1991'. What would be its activity two months earlier?
1.0 microcurie
0.5 microcurie
4 microcurie
8 microcurie
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
The nucleus 48Cd115, after two successive β-decay will give
46Pa115
49In115
50Sn113
50Sn115
