Tag: nuclear force and binding energy

Questions Related to nuclear force and binding energy

The angular momentum of electrons in an atom produces:

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

  1. light

  2. nuclear fission

  3. magnetic moment

  4. zeeman effect

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Correct Option: A

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

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

  1. 6.4 Mev

  2. 119 Mev

  3. 238 Mev

  4. 476 Mev

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Correct Option: C

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

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

  1. 54.4 eV

  2. 62.6 eV

  3. 72.6 eV

  4. 58.6 eV.

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Correct Option: A
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 $-(-54.4eV)=54.4eV$

What is the maximum value of binding energy per nucleon ?

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

  1. 8 MeV

  2. 8.8 MeV

  3. 7.6 MeV

  4. 1.1 MeV

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Correct Option: B
Explanation:

Answer is (B)

The Binding energy curve reaches a maximum value of 8.79

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

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

  1. a, b

  2. b, c

  3. c, d

  4. a, d

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Correct Option: A
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.

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

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

  1. $F _{pp}>F _{pn}= F _{nn}$

  2. $F _{pp}=F _{pn}= F _{nn}$

  3. $F _{pp}>F _{pn}> F _{nn}$

  4. $F _{pp}< F _{pn}= F _{nn}$

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Correct Option: B
Explanation:

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

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

Among the following, short range, charge independent and spin dependent forces are

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

  1. Gravitational forces

  2. Nuclear forces

  3. Electromagnetic forces

  4. Weak forces

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Correct Option: B
Explanation:

Nuclear force is short range, charge independent and spin independent force.

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

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

  1. Electrostatic and nuclear

  2. Electrostatic and gravitational

  3. Gravitational and nuclear

  4. Electrostatic

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Correct Option: C
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.

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

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

  1. nuclear interaction

  2. gravitational interaction

  3. electrostatic interaction

  4. electromagnetic interaction

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Correct Option: B
Explanation:

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

Two protons attract each other when the distance between them is 

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

  1. $10^{-18}$m

  2. $10^{-20}$m

  3. $10^{-15}$m

  4. $10^{-22}$m

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Correct Option: C
Explanation:

Two protons attracts each other when distance between them is less than $10^{-15}m.$