Tag: nuclear reactions

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Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

Inside nucleus, protons are held together though they have the dame charge. Why?

  1. The strong attractive nuclear force far exceeds the electrostatic force between the protons

  2. Neutrons prevent them from repelling from each other

  3. The electrostatic attractive force between an electron and a proton is more than the electrostatic repulsive force between the protons

  4. Gluons are responsible for holding them together
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Protons within a nucleus experience strong electrostatic repulsion due to their positive charges. The strong nuclear force, which is an attractive force acting between nucleons at very short ranges, is significantly stronger than this electrostatic repulsion, thereby holding the nucleus together.

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

The conversion of 1 u of mass results in ________ eV of energy.

  1. $9.315 \times 10^6$
  2. $391.5 \times 10^6$
  3. $931.5 \times 10^6$
  4. $93.15 \times 10^6$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

According to Einstein's mass-energy equivalence principle, 1 atomic mass unit (u) is equivalent to approximately 931.5 MeV of energy. Since 1 MeV equals 10^6 eV, 931.5 MeV equals 931.5 * 10^6 eV.

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

Magnitude of mass defect is a measure of ......................... of a nucleus.

  1. Unstability

  2. Stability

  3. Charge

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

Mass defect represents the difference between the mass of a nucleus and the sum of the masses of its individual nucleons. A larger mass defect corresponds to a higher binding energy per nucleon, which indicates greater nuclear stability.

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

In a laboratory experiment on emission from atomic hydrogen in a discharge tube, only a small number of lines are observed where as a lines are present in the hydrogen spectrum of a star. This is because in a laboratory  

  1. The amount of hydrogen taken is much smaller than that present in the star

  2. The temperature of hydrogen is much smaller than that of the star

  3. The pressure of hydrogen is much smaller than that of the star

  4. The gravitational pull is much larger than that in the star
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In a laboratory discharge tube, the low pressure of hydrogen gas limits the number of collisions and the population of excited states, resulting in fewer observed spectral lines compared to the high-pressure, high-temperature environment of a star.

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

Ionization energy of $Li$(Lithium) atom in ground state in $5.4 eV$. Binding energy of an electron in $Li^+$ ion in ground state is $75.6 eV$. Energy required to remove all three electrons of Lithium (Li) atom is:-

  1. $203.4 \ eV$
  2. $135.4 \ eV$
  3. $81.0 \ eV$
  4. $156.6 \ eV$
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

In a hypothetical star,two carbon nuclei fuse to form magnesium.The reaction is:(take :$1amu=931MeV/c^2)$
$^{12}C+^{12}C\rightarrow ^{24}Mg$
The energy released per carbon nuclei is: (Mass of $^{24}Mg=23.985amu)$

  1. $13.965 MeV$
  2. $11.12 MeV$
  3. $6.982 MeV$
  4. $10.12 MeV$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$^{12}C+^{12}C\rightarrow ^{24}Mg$
mass of $^{12}C=12.0642 amu$
Total input mass $m _1=2\times 12.0642$
$=24.1284$ amu
Mass of $^{24}Mg$=output mass
$=m _0=23.955$
mass loss $=m _1-m _o$
$Am=24.1284-23.985$
$=0.1434 amu$
Energy released $=0.1434\times 931 Mev$
$=13.965 Mev$

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

One mole of radium has an activity of 1/3.7 killo curie. Its decay constant will be 

  1. $\frac{1}{6}\times -10s^{-1}$
  2. $ 10^{-10}s^{-1}$
  3. $ 10^{-11}s^{-1}$
  4. $ 10^{-8}s^{-1}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Number of mole of radium, $n=1$

The number of nuclei of radium, $N={{N} _{a}}=avagdaro\,\,number=6.023\times {{10}^{23}}$

Activity, $A=\lambda N$

$ \because 1\,\,curie=3.7\times {{10}^{10}}\,decay/\sec  $

$ \dfrac{1}{3.7}\,kilocurie=0.27\,kilocurie=9.99\times {{10}^{12}}\,dacay/\sec  $

So, $\lambda =\dfrac{A}{N}=\dfrac{9.99\times {{10}^{12}}}{6.023\times {{10}^{23}}}=1.65\times {{10}^{-11}}\,$