In nuclear fission process, energy is released because [2001]

1. mass of products is more than mass of nucleus.

2. total binding energy of products formed due to nuclear fission is more than that the parent fissionable material.

3. total binding energy of products formed due to nuclear fission is less than parent fissionable material.

4. mass of some particles is converted into energy.

The average binding energy of a nucleon inside an atomic nucleus is about [1989]

1. 8 MeV

2. 8 eV

3. 8 J 

4. 8 erg

A nucleus with Z = 92 emits the following in a sequence:

$\alpha , {\beta }^{-}, {\beta }^{-}, \alpha , \alpha , \alpha , \alpha , \alpha , {\beta }^{-},{\beta }^{-}, \alpha , {\beta }^{+}, {\beta }^{+}, \alpha$. The Z of the resulting nucleus is [AIEEE 2003]

1. 74 

2. 76 

3. 78

4. 82

In nuclear fission, the percentage of mass converted into energy is about

1.  1%

2.  0.1%

3.  0.01%

4.  10%

The mass number of helium is 4 and that for suphur is 32. The radius of sulphur nuclei is larger than that of helium by

1.  $\sqrt{8}$

2.  4

3.  2

4.  8

In the nuclear decay given below

${}_{\mathrm{z}}{}^{\mathrm{A}}\mathrm{X} \stackrel{}{\to } {}_{\mathrm{Z} + 1}{}^{\mathrm{A}}\mathrm{Y} \stackrel{}{\to } {}_{\mathrm{Z} - 1}{}^{\mathrm{A} - 4}\mathrm{B}_{*} \stackrel{}{\to } {}_{\mathrm{Z} - 1}{}^{\mathrm{A} - 4}\mathrm{B},$

$\mathrm{The} \mathrm{particles} \mathrm{emitted} \mathrm{in} \mathrm{the} \mathrm{sequence} \mathrm{are}$
$$

1.  $\mathrm{\beta }, \mathrm{\alpha }, \mathrm{\gamma }$

2.  $\mathrm{\gamma }, \mathrm{\beta }, \mathrm{\alpha }$

3.  $\mathrm{\beta }, \mathrm{\gamma }, \mathrm{\alpha }$

4.  $\mathrm{\alpha }, \mathrm{\beta }, \mathrm{\gamma }$

$In the nucleus of {}_{11}{}^{23}Na, \mathrm{the} \mathrm{number} \mathrm{of} \mathrm{protons}, \mathrm{neutrons} \mathrm{and} \mathrm{electrons} \mathrm{are}$:

1.  11, 12, 0

2.  23, 12, 11

3.  12, 11, 0

4.  23, 11, 12

A thorium nucleus is formed when a uranium nucleus emits an $\mathrm{\alpha } - \mathrm{particle}$. 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 ${\mathrm{A}}_0$ in a period of 7 years. After a further lapse of 7 years, its activity will be:

1.  ${\mathrm{A}}_0$ $$ $$

2.  $\frac{2}{3}{\mathrm{A}}_0$ $$ $$

3.  $\frac{{\mathrm{A}}_0}{6}$ $$ $$

4.  $\frac{{\mathrm{A}}_0}{9}$

The radius of Germanium (Ge) nuclide is measured to be twice the radius of ${}_4{}^9\mathrm{Be}$. The number of nucleons in Ge is:

1. 73

2. 74

3. 75

4. 72