Tag: atomic nuclei

Quizzes (8) Questions (121)

Questions Related to atomic nuclei

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

Choose the correct statement :

  1. A nucleus is relatively more stable for which total binding energy is more.

  2. A nucleus is relatively more stable for which binding energy per nucleon is more.

  3. A nucleus is relatively more stable for which total binding energy is low.

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Binding energy is the amount of energy required to separate a particle from a system of particles or to disperse all the particles of the system. Binding energy is especially applicable to subatomic particles in atomic nuclei, to electrons bound to nuclei in atoms, and to atoms and ions bound together in crystals. Binding energy is more if the nucleus is relatively more stable.

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

$1$ $a.m.u$ is equivalent to 

  1. $931$ $MeV$
  2. $139$ $MeV$
  3. $93$ $MeV$
  4. $39$ $MeV$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$m=1\ a.m.u.=1.66\times10^{-27}kg$

Its energy equivalent, using $E=mc^2$ is $E=1.49\times10^{-10}\ J$.
or $E=1.49\times10^{-10}/1.6\times10^{-13}\ MeV=931\ MeV$

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

The binding energy per nucleon of deuteron $ \left( \frac { 2 }{ 1 }  H \right)  $ and helium nucleus $ \left( \frac { 4 }{ 2 } He \right)  $ is.1.1 meV and 7 meV respectively. If two deuteron nuclei react to from s single helium nucleus, then the energy released is:

  1. 13.9 MeV

  2. 26.9 MeV

  3. 23.6 MeV

  4. 19.2 MeV
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total binding energy of two deuterons = 2 × 2.2 = 4.4 MeV. Total binding energy of helium = 4 × 7 = 28 MeV. Energy released = 28 - 4.4 = 23.6 MeV. Note: This is another duplicate with 'meV' typo (should be MeV).

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

The binding energy expressed in $MeV$ is given for the following nuclear reactions :
$ _2He^3+\ _0n^1\rightarrow\ _2He^4+20\ MeV$
$ _2He^4+\ _0n^1 \rightarrow\ _2He^5 -0.9\ MeV$
Which of the following conclusions are correct ?

  1. $ _2He^4$ is less stable than both $ _2He^3$ and $ _2He^5$
  2. $ _2He^4$ is less stable than $ _2He^3$ but more stable than $$ _2He^5$
  3. $ _2He^4$ is less stable than $ _2He^5$ but more stable than $$ _2He^3$
  4. $ _2 He^4$ is more stable than both $ _2He^3$ and $ _2He^5$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A positive energy release (Q > 0) indicates a stable product, while a negative energy release (Q < 0) indicates an unstable product. Since the first reaction releases 20 MeV, He-4 is more stable than He-3. Since the second reaction requires 0.9 MeV, He-5 is less stable than He-4.

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

An electron and a positron are moving side by side in the positive $x-$direction at $1.5\times 10^8\ m/s$. When they annihilate each other, two photons are produced that move along the $x-$axis, then : 

  1. both move in positive $x-$direction
  2. both move in positive direction along $x-$axis

  3. both may move in same direction
  4. both $(a)$ and $(c)$ are correct
Reveal answer Fill a bubble to check yourself
B Correct answer
Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

In nuclear reaction
$ _{2}He^{4}+\ _{Z}X^{A}\rightarrow Z+\  _{2}\gamma^{A+3}+\ _{Z}M^{A}$
where $M$ denotes

  1. electron

  2. positron

  3. proton

  4. neutron
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In the reaction, we need to identify what M represents. Based on nuclear reaction notation and the fact that it appears after the product nucleus, M is a neutron that is emitted in the reaction. The reaction shows helium-4 bombarding target X, producing an excited nucleus that emits gamma rays and a neutron.