Nuclei practice · Mixed difficulty

What is used as a moderator in a nuclear reactor?

The nuclei of which of the following pairs of nuclei are isotones

During the $\mathrm{\beta } - \mathrm{decay}$

How much energy must a gamma ray photon have, if it is to materialize into a pair of electron and positron with each particle having a K.E of 1MeV?

A nucleus of mass number 189 splits into two nuclei having mass number 125 and 64. The ratio of radius of two daughter nuclei respectively is

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

During a nuclear fusion reaction

The correct order of ionizing capacity of $\alpha ,\beta$ and $\gamma -$ rays is

The approximate nuclear radius is proportional to ($A$ is the mass number and $Z$ the atomic number)

A radioactive substance ${ }_{84}^{218} {X}$ undergoes following decay:

${ }_{84}^{218} {X} \stackrel{\alpha \text {-Decay }}{\longrightarrow} {A} \stackrel{\beta^{-} \text {-Decay }}{\longrightarrow} {B} \stackrel{\alpha \text {-Decay }}{\longrightarrow} {C} \stackrel{\beta^{+}-\text {Decay }}{\longrightarrow} {D} \stackrel{\gamma \text {-Decay }}{\longrightarrow} {Y}$

Then product ${Y}$ is :

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

Some radioactive nucleus may emit

Half life of radioactive element depends upon

The functions of moderators in nuclear reactor is to

Which of the following isotopes is normally fissionable

The penetrating power of $\alpha$-rays is

One Becquerel is defined as

In the following reaction
$_{12}M{g^{24}}{ + _2}H{e^4}{ \to _{14}}S{i^X}{ + _0}{n^1},X$ is

Two lithium nuclei in a lithium vapour at room temperature do not combine to form a carbon nucleus because

If the total binding energies of ${ }_1^2 \mathrm{H},{ }_2^4 \mathrm{He},{ }_{26}^{56} \mathrm{Fe} \&{ }_{92}^{235} \mathrm{U}$ nuclei are $2.22,28.3,492$ and $1786 \mathrm{~MeV}$ respectively, identify the most stable nucleus of the following.

Isotopes are atoms having

$_{92}{\mathrm{U}^{235}}$ and $_{92}{\mathrm{U}^{238}}$ differ as

Which of these is a fusion reaction

Find out the mass of Uranium required per day to operate 0.95 MW nuclear power plant using $_{92}{U^{235}}$ fission.

Statement-I: The BE per nucleon of the fused heavier nuclei is more than the B.E per nucleon of the lighter nuclei.

Statement-II: The final system is more tightly bound to the initial system.

Age of a tree is determined using radio-isotope of

A fission reaction is given by ${ }_{92}^{236} {U} \rightarrow{ }_{54}^{140}{Xe}+{ }_{38}^{94} {Sr}+x+y,$ where ${x}$ and ${y}$ are two particles. Considering ${ }_{92}^{236} U$ being at rest, the kinetic energies of the products are denoted by ${K}_{X e}, K_{S r}, K_x(2 \mathrm{~MeV})$ and $K_y(2 \mathrm{~MeV}),$ respectively. Let the binding energies per nucleon of ${ }_{92}^{236} {U},{ }_{54}^{140} {Xe},{ }_{38}^{94} {Sr}$ be $7.5 \mathrm{~MeV}, 8.5 \mathrm{~MeV}$ and $8.5 \mathrm{~MeV}$ respectively. Considering different conservation laws, the correct option is

Which of the following sequence for the emission of radioactive radiations are followed for a given reaction?

${ }_{\mathrm{z}} \mathrm{X}^{\mathrm{A}} \longrightarrow{ }_{\mathrm{z}+1} \mathrm{Y}^{\mathrm{A}} \longrightarrow { }_{\mathrm{z}-1} \mathrm{~K}^{\mathrm{A}-4} \longrightarrow { }_{\mathrm{z}-1} \mathrm{~K}^{\mathrm{A}-4}$

After one $\alpha$-decay and two consecutive $\beta$-decays, the daughter nucleus is an isotope of the

If the mass defect during the formation of lithium from hydrogen is $0.5 \%$, what will be the energy obtained in forming lithium from $1 \mathrm{~kg}$ of hydrogen?