Nuclei practice · Mixed difficulty

Choose the incorrect statement about the strong nuclear force.

Consider $\alpha - \mathrm{Particles},\,\,\mathrm{\beta } - \mathrm{Particles }\,\,\mathrm{and}\,\,\gamma - \mathrm{rays}$, each having an energy of $\mathrm{0}\mathrm{.5 }\,\mathrm{MeV}$. In increasing order of penetrating powers, the radiations are

A uranium reactor develops thermal energy at a rate of 300 MW. Calculate the amount of ${ }^{235} \mathrm{U}$ being consumed every second. Average energy released per fission is $200 \mathrm{~MeV}$.

A radioactive isotope $\mathrm{X}$ with a half-life of $1.37\,\, \times \,\,{10^9}$ years decays to $Y$ which is stable. A sample of rock from the moon was found to contain both the elements $X$ and $Y$ which were in the ratio $\mathrm{1:7}$. The age of the rock is

The half life period of radioactive nucleus is 12.5 hours and its mass is 256 gm. The time after which amount of remaining substance is 1gm will be...... hours

Which is the correct expression for half-life

For a nucleus ${ }_Z^A X$ having mass number ${A}$ and atomic number ${Z}$

A. The surface energy per nucleon $\left(b_s\right)=a_1 A^{2 / 3}$

B. The coulomb contribution to the binding energy $b_c=-a_2 \frac{Z(Z-1)}{A^{4 / 3}}$

C. The volume energy $b_v=a_3 A$

D. Decrease in the binding energy is proportional surface area.

E. While estimating the surface energy, it is assumed that each nucleon interacts with 12 nucleons,
( $a_1, a_2$ and $a_3$ are constants)

Choose the most appropriate answer form the options given below;

Half-lives of two radioactive substances A and B are respectively $20 \mathrm{~min}$. and $40 \mathrm{~min}$. initially, the samples of $\mathrm{A}$ and $\mathrm{B}$ have equal number of nuclei. After $80 \mathrm{~min}$, the ratio of the remaining nuclei of $\mathrm{A}$ and $B$ is

Atomic reactor is based on

Mark the correct statement

The size of an atom is of the order of

A ${\pi ^0}$ at rest decays into $2\gamma$ rays, ${\pi ^0} \to \gamma + \gamma$. Then which of the following can happen

Two radioactive substances $X$ and $Y$ initially contain equal number of nuclei. $X$ has a half-life of 1 hour and $Y$ has a half-life of 2 hours. After two hours, the ratio of the activity of ${X}$ to the activity of ${Y}$ is :-

If the binding energy per nucleon of deuteron is $1.115 \,{MeV}$, then its mass defect (in amu) is

In the nuclear reaction
${ }_1 {H}^2+{ }_1 {H}^2 \longrightarrow{ }_2 {He}^3+{ }_0 n^1$

Mass of deuterium atom $=2.014741 \,\mathrm{amu}$, Mass of ${ }_2 {He}^3$ atom $=3.016977 \mathrm{~amu}$, and Mass of neutron $=1.008987 \mathrm{~amu}.$
The $Q$-value of the reaction will be:

Which shows radioactivity?

The mass defect for the nucleus of helium is $0.0303\,\,a.m.u.$ What is the binding energy per nucleon for helium in $MeV$

A chain reaction is continuous due to

Neutrino emission in $\mathrm{\beta } - \mathrm{decay}$ was predicted theoretically by

A nucleus with $Z = 92$ emits the following in a sequence : $\mathrm{\alpha },\mathrm{\alpha },{\mathrm{\beta }^ - },{\mathrm{\beta }^ - },\mathrm{\alpha },\mathrm{\alpha },\mathrm{\alpha },\mathrm{\alpha }:{\mathrm{\beta }^ - },{\mathrm{\beta }^ - },\mathrm{\alpha },{\mathrm{\beta }^ + },{\mathrm{\beta }^ + },\mathrm{\alpha }$. The $Z$ of the resulting nucleus is

Which of these is a fusion reaction

There are two radioactive substances $A$ and $B$. Decay constant of $B$ is two times that of $A$. Initially, both have equal number of nuclei. After $n$ half lives of $A$, rate of disintegration of both are equal. The value of $n$ is

Density of nucleus is of the order of

Beta decay of a free neutron takes place with a half life of 14 minutes. Then find (a) decay constant (b) energy liberated in the process.

A nucleus of mass $\mathrm{214}$ amu in free state decays to emit an $\alpha$-particle. Kinetic energy of the $\alpha$-particle emitted is $6.7\,MeV$. The recoil energy (in $MeV$) of the daughter nucleus is

Choose the wrong statement.

Assertion: ${ }_1^3 {H}$ isotope does not undergo fusion of the type ${ }_1^3 {H}+{ }_1^2 {H} \rightarrow$ as it is rarely found in nature.
Reason: ${ }_1^3 {H}$ has half life of $> >12$ years.

The phenomena in which proton flips is

Which one is correct about fission?

The average binding energy per nucleon is maximum for the nucleus