If the half lives of a radioactive element for and β decay are 4 years and 12 years respectively, the ratio of its initial activity and that after 12 years will be
6.25 %
12.5 %
25 %
50 %
A.
6.25 %
The half lives of a radioactive element and β decay are 4 and 12 years respectively.
T =
=
T = 3
n =
=
n = 4
=
= 6.25 %
A radioactive nucleus is being produced at a constant rate per second. Its decay constant is λ. If N0 are the number of nuclei at time t = 0, then the maximum number of nuclei possible are
N0 +
N0
+ N0
Assertion: Nuclei having mass number about 60 are most stable.
Reason: When two or more light nuclei are combined into a heavier nucleus, then the binding energy per nucleon will increase.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
N1 atoms of a radioactive element emit N2 beta particles per second. The decay constant of the element is ( m s-1 )
N1/N2
N2/N1
N1 ( ln2 )
N2 ( ln2 )
Assertion: 90Sr from the radioactive fall out from a nuclear bomb ends up in the bones of human beings through the milk consumed by them. It causes impairment of production of red blood cells.
Reason: The energies β-particles emitted in the decay of 90Sr damage the bone marrow.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
What is the amount of energy released by deuterium and tritium fusion? [ Given: =2.0141024 u, = 3.0160504 , = 1.0086654 u ]
60.6 eV
12.6 eV
17.6 eV
28.3 eV
Calculate power output of reactor, if it is takes 30 days to use up 2 kg of fuel, and if each fission gives 185 MeV of useable energy. Avogadro's number = 6 × 1023 / mol?
56.3 MW
60.3 MW
58.3 MW
54.3 MW
Assertion: Heavy water is a better moderator than normal water.
Reason: Heavy water absorbs neutrons more efficiently than normal water.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion: 94Sr from the radioactive fall out from a nuclear bomb ends up in the bones of human beings through the milk consumed by them. It causes impairment of the production of red blood cells.
Reason: The energetics β-particles emitted in the decay of 94Sr damage the bone marrow.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false