Tag: the nuclear force

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Questions Related to the nuclear force

Multiple choice physics nuclei nuclear force the nuclear force nuclear force and binding energy

The binding energy per nucleon for $\mathrm { U } ^ { 238 }$ about 7.5Mev where as it is about 8.5 Mev for a nucleus having a mass half of Uranium. If $\mathrm { U } ^ { 238 }$ splits into two exact halves the energy released would be

  1. 6.4 Mev

  2. 119 Mev

  3. 238 Mev

  4. 476 Mev
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Energy released = (Total binding energy of products) - (Total binding energy of reactants). Reactants: 238 nucleons * 7.5 MeV = 1785 MeV. Products: 2 * (119 nucleons * 8.5 MeV) = 2023 MeV. Energy released = 2023 - 1785 = 238 MeV.

Multiple choice physics nuclei nuclear force the nuclear force nuclear force and binding energy

The excitation energy of a hydrogen like ion to first excited state is 40.8 eV. The energy needed to remove the electron from the ion the ground state is

  1. 54.4 eV

  2. 62.6 eV

  3. 72.6 eV

  4. 58.6 eV.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For a hydrogen atom like system the energy for $n^{th}  $ level is given by $E _n=\dfrac{-13.6Z^2}{n^2}eV$

So the ground state energy will be $E _1=\dfrac{-13.6Z^2}{1}eV$
and for the state $n=2$ the energy is $E _2=\dfrac{-13.6Z^2}{4}eV$
So the excitation energy foe this state will be $E _2 -E _1=10.2Z^2eV$
as it is given to be $40.8eV$  so $Z^2=4$ or $Z=2$
So the energy in ground state will be $E _1=-54.4eV$
so the inonization energy will be $-(-54.4eV)=54.4eV$

Multiple choice physics nuclei nuclear force the nuclear force nuclear force and binding energy

Identify the correct statement/statements:
a) At greater distances nuclear forces are negligible
b) Nuclear forces are non central forces
c) Nuclear forces are weakest in nature
d) Nuclear forces are charge dependent forces

  1. a, b

  2. b, c

  3. c, d

  4. a, d
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Nuclear forces properties :
1) They will act upto nearly one ferms. Beyond that they become negligible.
2) Charge independent : $F _{pp} = F _{pn} = F _{nn}$
3) They do not act along the line joining the centres of the nuclears, so they are non-central forces.
4) Nuclear forces are strong in nature.
So, correct choice is option A.

Multiple choice physics nuclei nuclear force the nuclear force nuclear force and binding energy

Let $F _{pp},F _{pn}$ and $F _{nn}$ denote the magnitudes of the nuclear force by a proton on a proton, by a proton on a neutron and by a neutron on a neutron respectively when the separation is less than one Fermi. Then

  1. $F _{pp}>F _{pn}= F _{nn}$
  2. $F _{pp}=F _{pn}= F _{nn}$
  3. $F _{pp}>F _{pn}> F _{nn}$
  4. $F _{pp}< F _{pn}= F _{nn}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

At separation less than one fermi,  the nuclear force of attraction is strongly active and Nuclear force is charge independent force.

Hence , $F _{pp} = F _{pn} = F _{nn}$

Multiple choice physics nuclei nuclear force the nuclear force nuclear force and binding energy

Among gravitational,electrostatic and nuclear forces,the two attractive forces between two neutrons are

  1. Electrostatic and nuclear

  2. Electrostatic and gravitational

  3. Gravitational and nuclear

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

Neutrons have no charge on them. So, there is no electrostatic force. But we have gravitational and nuclear forces on two neutrons because neutrons have masses and gravitational force depends on mass.
So, correct choice is option C.

Multiple choice physics nuclei nuclear force the nuclear force nuclear force and binding energy

Among the following interactions, the one of least significance in nuclear physics is

  1. nuclear interaction

  2. gravitational interaction

  3. electrostatic interaction

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

Since, masses of electrons, protons and neutrons are negligible. So, we often neglect gravitational interaction in nuclear physics.