Physics

Nuclear and Atomic Physics

571 Questions

Nuclear and atomic physics explores the components and properties of the nucleus, including isotopes, radioactive decay, and fundamental forces. These concepts are essential for various competitive exams requiring a strong foundation in physics. The provided questions cover structural properties, mass, energy equivalence, and particle interactions.

Nucleus propertiesIsotopes and mass numberAlpha particle scatteringNuclear forcesMass energy equivalenceBeta particle emission

Nuclear and Atomic Physics Questions

Multiple choice determination of atomic and isotopic mass some basic concepts of chemistry chemistry

The table shows the numbers of particles present in the nuclei of four atoms or ions.

protons neutrons electronic structure
$1$ $18$ $22$ $2, 8, 8$
$2$ $19$ $20$ $2, 8, 8$
$3$ $19$ $21$ $2, 8, 8, 1$
$4$ $20$ $20$ $2, 8, 8, 2$

Which two particles belong to the same element?

  1. $1$ and $2$
  2. $1$ and $4$
  3. $2$ and $3$
  4. $2$ and $4$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$\text{An element always consist same number of proton and electrons.}$

$\text{Number of neutrons can be changed in an element based on its isotrops.}$
$\text{Option C is correct.}$

Multiple choice deflection of electron beam by magnetic field observing the force and electron beam tubes charged particles electromagnetic forces physics

The minimum amount of energy released in annihilation of electron-positron is.

  1. $1.02\ MeV$
  2. $0.58\ MeV$
  3. $185\ MeV$
  4. $200\ MeV$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Energy released during the annihilation of ${ e }^{ - },{ e }^{ + }$ pair is,
$E=2{ m } _{ c }{ C }^{ 2 }$
$E=2\times 9.1\times { 10 }^{ -31 }\times { \left( 3\times { 10 }^{ 8 } \right)  }^{ 2 }J$
$E=\dfrac { 2\times 9.1\times 9\times { 10 }^{ -15 } }{ 1.6\times { 10 }^{ -13 } } MeV$
$E=1.02MeV$
Multiple choice chemistry inside the atom history of atomic model atomic theory of dalton daltons atomic theory

The nucleus of the atom $\left( Z>1 \right) $ consists of:

  1. Proton and neutron.

  2. Proton and electron.

  3. Neutron and electron.

  4. Proton, neutron and electrons
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The atomic nucleus is the central area of the atom. It is composed of two kinds of subatomic particles: protons and neutrons.The protons and neutrons held together to form the dense area of the nucleus.

For atoms havng $Z>1$ nucleus contains protons and neutrons.

Multiple choice physics nuclei gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

A free nucleus of mass $24$ u emits a gamma photon [when initially at rest]. The energy of the photon is $7$ MeV. The recoil energy of the nucleus in keV is 

  1. $1.1$
  2. $1.2$
  3. $1.0$
  4. $1.3$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Using conservation of momentum, the recoil energy E_r = (E_gamma)^2 / (2 * M * c^2). With E_gamma = 7 MeV and M = 24 u (approx 24 * 931.5 MeV/c^2), the recoil energy is approximately 1.1 keV.

Multiple choice gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

What is energy released in the $\beta  - decay\;of{\;^{32}}P{ \to ^{32}}S?$(Given:atomic masses:31.97391 u for $\left( {^{32}P\;and\;31.97207\;u\;fo{r^{32}}S} \right)$

  1. -1.2 MeV
    • 1.7 MeV

  3. +2.1 MeV

  4. -0.9 Mev
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Released energy will be corresponding the $mass $ $defect$ $\text{which is difference in mass of parent nuclei and daughter nuclei}$

so mass defect is $31.97391u- 31.97207 u=0.00184u=0.00184\times 931Mev=1.7Mev$ 
as $1u=931MeV $ of $ energy$.
Option B is correct.

Multiple choice gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

A $ _6C^{12} $ nucleus is to be divided into 3 alpha particles . the amount of energy required to achieve this ( mass of an alpha particle=4.00388 u ) is

  1. 3.405 MeV

  2. 10.837 MeV

  3. 8.133 MeV

  4. 12.573 MeV
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The mass defect is calculated by subtracting the mass of 3 alpha particles (3 * 4.00388 u) from the mass of the C-12 nucleus (12.00000 u). The energy is then E = mass_defect * 931.5 MeV/u.

Multiple choice gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

A stationary nucleus of mass $24\ amu$ emits a gamma photon. The energy of the emitted photon is $7\ MeV$. The recoil energy of the nucleus is:

  1. $2.2\ keV$
  2. $1.1 keV$
  3. $3.1\ keV$
  4. $22\ keV$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The energy of emitted photon, $E=hf=7 MeV$

If $p$ be the momentum of photon and $v$ be the recoil velocity of nucleus, then by conservation of momentum 
$p=mv$ or $E/c=mv$ or $v=E/mc$
Thus, recoil energy $K=\dfrac{1}{2}mv^2=\dfrac{m}{2}\times \dfrac{E^2}{m^2c^2}=\dfrac{E^2}{2mc^2}=\dfrac{(7 MeV)^2}{2\times (24\times 931.5 MeV)}=1.09 \times 10^{-3} MeV=1.1 keV$
where $(1 amu=931.5 meV)$

Multiple choice gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

Consider the following nuclear reaction:
$X^{200}\rightarrow A^{110}+B^{90}+Energy$
If the binding energy per nucleon for $X$, $A$ and $B$ are $7.4\ MeV$, $8.2\ MeV$ and $8.2\ MeV$ respectively, the energy released will be:

  1. $90\ MeV$
  2. $110\ MeV$
  3. $200\ MeV$
  4. $160\ MeV$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Binding energy of $X$: $E _X = 200\times 7.4 = 1480MeV$

Binding energy of  $A$: $E _A = 110\times 8.2 = 902MeV$
Binding energy of  $B$: $E _B = 90\times 8.2 = 738MeV$
$\therefore$ energy released, $E = E _A+E _B- E _X = 902+738-1480 =160MeV$

Multiple choice gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

In a $\gamma -$decay process, $\gamma-$rays of energy $E$ is emitted. Find the decrease in internal energy of mass $M$ (of nucleus).

  1. $\dfrac{E^2}{2Mc^2}$
  2. $E - \dfrac{E^2}{2Mc^2}$
  3. $E+\dfrac{E^2}{2Mc^2}$
  4. $E+\dfrac{E^2}{Mc^2}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

By momentum conservation:
$\cfrac{E}{c} = Mv$
$ v = \cfrac{E}{Mc}$

Now, total decrease in internal energy $=$ Energy of $\gamma$ $+$ $KE$ of $M$
                                                                 $ = E + \cfrac{1}{2} Mv^2$
                                                                 $ = E + \cfrac{E^2}{2Mc^2}$

Multiple choice gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

Mark out the correct statement(s)

  1. in alpha decay, the energy released is shared between alpha particle and daughter nucleus in the form of kinetic energy and share of alpha particle is more than that of the daughter nucleus

  2. in beta decay, the energy released is in the form of kinetic energy of beta particles

  3. in beta minus decay, the energy released is shared between electron and antineutrino

  4. in gamma decay, the energy released is in the form of energy carried by photons termed as gamma rays
Reveal answer Fill a bubble to check yourself
A,C,D Correct answer
Explanation

in alpha decay, the energy released is shared between alpha particle and daughter nucleus in the form of kinetic energy and share of alpha particle is more than that of the daughter nucleus

The following principles should be appied:
1. Conservation of momentum
2. Conservation of energy
3. Conservation of charge

If alpha has a lower mass
$E = \cfrac{p^2}{2m}$
momentum has to be same for both the product particles, hence lower mass has higher kinetic energy.

in beta minus decay, the energy released is shared between electron and antineutrino In nuclear physics, beta decay (-decay) is a type of radioactive decay in which a proton is transformed into a neutron, or vice versa, inside an atomic nucleus. This process allows the atom to move closer to the optimal ratio of protons and neutrons.
3. in gamma decay, the energy released is in the form of energy carried by photons termed as gamma rays .
released when electrons transit from a higher energy state to a lower energy state,

Multiple choice gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

A free nucleus of mass $24 amu$ emits a gamma photon (when initially at rest). The energy of the photon is $7 MeV$. The recoil energy of the nucleus in $keV$ is

  1. $2.2$
  2. $1.1$
  3. $3.1$
  4. $22$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$ E = \cfrac{p^2}{2m}$

Conservation of momentum for photon:
$E = \cfrac{hc}{\lambda} = 7 MeV$
$p = \cfrac{h}{\lambda} = 7/c MeV$

Equating the momentum:
$ \cfrac{7}{c }= \sqrt{2E _{nucleus}m}$

Substitute $m = 24\ amu$,
Solving with appropriate units:
$ E _{nucleus} = 1.1\  KeV$

Multiple choice chemistry what is inside atom discovery of neutrons structure of atoms discovery of subatomic particles

The fundamental particle which has no charge and has mass almost equal to that of positively charged fundamental particle is ..............

  1. proton

  2. neutron

  3. electron
  4. $\beta$-particle
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The fundamental particle which has no charge and has mass almost equal to that of positively charged fundamental particle is neutron.