Q. No.A thorium nucleus is formed when a uranium nucleus emits an α - particle. The atomic number of thorium is
1. 92
2. 90
3. 82
4. 94
The activity of the radioactive element decreases to one-third of the original activity A0 in a period of 7 years. After a further lapse of 7 years, its activity will be:
1. A0
2. 23A0
3. A06
4. A09
The radius of Germanium (Ge) nuclide is measured to be twice the radius of Be94. The number of nucleons in Ge is:
1. 73
2. 74
3. 75
4. 72
if the binding energies of 21H,31H, and 42He are respectively a,b, and c (in MeV), then the energy in (MeV) released in this reaction is:
1. c+a−b
2. c−a−b
3. a+b+c
4. a+b−c
A radioactive nucleus X decays to a stable nucleus 'y'. The graph of the rate of formation of 'y' against time 't' will be:
| 1. |   |
2. |   |
| 3. |   |
4. |   |
A stationary radioactivity nucleus of mass 210 units disintegrates into an alpha particle of mass 4 units and residual nucleus of mass 206 units. If the kinetic energy of the alpha particles is E, the kinetic energy of the residual nucleus is
1. (2105) E
2. (2103) E
3. (103105) E
4. (1032) E
The mass number of a nucleus is
1. sometimes equal to its atomic number
2. sometimes less than and sometimes more than its atomic number
3. always less than its atomic number
4. always more than its atomic number
Two nucleons are at a separation of 1 fm. The net force between them is F1 if both are neutrons, F2 if both are protons and F3 if one is
proton and other is a neutron. Hence
1. F1 > F2 > F3
2. F2 > F1 > F3
3. F1 = F3 > F2
4. F1 = F2 > F3
In the nucleus of N2311a, the number of protons, neutrons and electrons are:
1. 11, 12, 0
2. 23, 12, 11
3. 12, 11, 0
4. 23, 11, 12
In the nuclear decay given below
XAz → YAZ + 1 → B*A - 4Z - 1 → BA - 4Z - 1,
The particles emitted in the sequence are
1. β, α, γ
2. γ, β, α
3. β, γ, α
4. α, β, γ
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