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
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
The nucleus 6C12 absorbs an energetic neutron and emits a beta particle (β). The resulting nucleus is
7N14
7N13
5B13
6C13
The binding energy per nucleon is maximum in case of
2He4
26Fe56
56Ba141
92U235
The nuclei 6C13 and 7N14 can be described as
isotones
isobars
isotopes of carbon
isotopes of nitrogen
Solar energy is due to
fusion reaction
combustion reaction
fission reaction
chemical reaction
The constituents of atomic nuclei are believed to be
neutrons and protons
protons only
electrons and protons
electrons, protons and neutrons
The most penetrating radiation out of the following is
γ-rays
α-particles
β-rays
χ-rays
What is the respective number of α and β particles emitted in the following radioactive decay
200X90 → 168Y80?
6 and 8
6 and 6
8 and 8
8 and 6
The count rate of a Geiger Muller counter for the radiation of a radioactive material of half-life 30 min decreases to 5 s-1 after 2 h. The initial count rate was.
20 s-1
25 s-1
80 s-1
625 s-1
