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New answer posted•a year ago

Nuclei Physics NCERT Exemplar Solutions Class 12th Chapter Thirteen

The gravitational force between a H atom and a another particle of mass m will be given newton’s law

F=GMm/r² where r in km

(a) M=m_proton+m_electron

(b) M=m_proton+m_electron-

(c) M is not relate to the mass of the hydrogen atom

(d) M=m_proton+m_electron-(|V|)= magnitude of the potential energy of electron in H atom.

5 Views|Posted a year ago

Asked by Alok Kumar Singh

Answered by

Alok Kumar Singh | Contributor-Level 10

a year ago

This is a Multiple Choice Questions as classified in NCERT Exemplar

Answer- b

Explanation- F=GMm/r²

M=effective mass of hydrogen atom=mass of electron +mass of proton -B²/c

B.E of hydrogen atom = 13.6eV

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New answer posted•a year ago

Nuclei Physics NCERT Exemplar Solutions Class 12th Chapter Thirteen

Suppose we consider a large number of containers each containing initially 10000 atoms of a radioactive material with a half life of 1 year. After 1 year,
(a) All the containers will have 5000 atoms of the material
(b) All the containers will contain the same number of atoms of the material but that number will only be approximately 5000
(c) The containers will in general have different numbers of the atoms of the material but their average will be close to 5000
(d) None of the containers can have more than 5000 atoms

1 Views|Posted a year ago

Asked by Alok Kumar Singh

Answered by

Alok Kumar Singh | Contributor-Level 10

a year ago

This is a Multiple Choice Questions as classified in NCERT Exemplar

Answer (c)

Explanation- it is a process in which metal decays spontaneously . so during a span of 1 year it will decay almost half of its original value so it will come close to 5000.

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New answer posted•a year ago

Nuclei Physics NCERT Exemplar Solutions Class 12th Chapter Thirteen

A nuclide 1 is said to be the mirror isobar of nuclide 2 if Z₁=N₂ and Z₂ = N₁ (a) What nuclide is a mirror isobar of ₁₁²³Na ? (b) Which nuclide out of the two mirror isobars have greater binding energy and why?

6 Views|Posted a year ago

Asked by Alok Kumar Singh

Answered by

Alok Kumar Singh | Contributor-Level 10

a year ago

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation- a nuclide 1 is said to be mirror isobar of nuclide 2, if Z₁=N₂ and Z₂= N₁

Now ₁₁Na²³, ₁₂Mg²³ for which Z₂=12=N₁ and N₂ =23-12=11=Z₁

(b) As ₁₂Mg²³ contain even number of protons against ₁₁Na²³ which has odd number o

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New answer posted•a year ago

Nuclei Physics NCERT Exemplar Solutions Class 12th Chapter Thirteen

Are the nucleons fundamental particles, or do they consist of still smaller parts? One way to find out is to probe a nucleon just as Rutherford probed an atom. What should be the kinetic energy of an electron for it to be able to probe a nucleon? Assume the diameter of a nucleon to be approximately 10^-15

2 Views|Posted a year ago

Asked by Alok Kumar Singh

Answered by

Alok Kumar Singh | Contributor-Level 10

a year ago

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation- Each particle (neutron and proton) present inside the nucleus is called nucleon .

Let $λ = 10^{- 15} m$

$λ = \frac{h}{p}$

and KE= PE

$E = h c / λ$ = $\frac{6.6 \times 10^{- 34} \times 3 \times 10^{8}}{10^{- 15} \times 1.6 \times 10^{- 19}}$ eV

K.E= 10⁹eV

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New answer posted•a year ago

Nuclei Physics NCERT Exemplar Solutions Class 12th Chapter Thirteen

A piece of wood from the ruins of an ancient building was found to have a ¹⁴C activity of 12 disintegrations per minute per gram of its carbon content. The ¹⁴C activity of the living wood is 16 disintegrations per minute per gram. How long ago did the tree, from which the wooden sample came, die? Given half-life of ¹⁴C is 5760 yr.

6 Views|Posted a year ago

Asked by Alok Kumar Singh

Answered by

Alok Kumar Singh | Contributor-Level 10

a year ago

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation- R= 12dis/min per gm and R₀= 16dis/min per gm T_1/2= 5760yr

R= $e^{- λ t}$ $e^{λ t}$

By taking log

$λ t l o g e = l o g \frac{R_{0}}{R}$

$λ t$ = log₁₀16/12 $\times 2.303$

$t = \frac{2.303 (l o g 4 - l o g 3)}{λ}$

= 2.303 (0.6020-4.771)5760/0.6931

= 2391.20yr

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New answer posted•a year ago

Nuclei Physics NCERT Exemplar Solutions Class 12th Chapter Thirteen

Consider a radioactive nucleus A which decays to a stable nucleus C through the following sequence:

A -> B -> C

Here B is an intermediate nuclei which is also radioactive. Considering that there are N₀ atoms of A initially, plot the graph showing the variation of number of atoms of A and B versus time.

4 Views|Posted a year ago

Asked by Alok Kumar Singh

Answered by

Alok Kumar Singh | Contributor-Level 10

a year ago

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation-

by considering the graph at t=0 N_A= N_o while N_B=0 but when time increases the atoms in B also increases and becomes maximum and then drop to zero by radioactive decay law.

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New answer posted•a year ago

Nuclei Physics NCERT Exemplar Solutions Class 12th Chapter Thirteen

Why do stable nuclei never have more neutrons than protons?

3 Views|Posted a year ago

Asked by Alok Kumar Singh

Answered by

Alok Kumar Singh | Contributor-Level 10

a year ago

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation-because more number of protons means more repulsive force which leads to instability.

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New answer posted•a year ago

Nuclei Physics NCERT Exemplar Solutions Class 12th Chapter Thirteen

In pair annihilation, an electron and a positron destroy each other to produce gamma radiations. How is the momentum conserved?

6 Views|Posted a year ago

Asked by Alok Kumar Singh

Answered by

Alok Kumar Singh | Contributor-Level 10

a year ago

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation- during the collision of electron and positron they form gamma radiation and these gamma particle travels in opposite direction to conserve the momentum.

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New answer posted•a year ago

Nuclei Physics NCERT Exemplar Solutions Class 12th Chapter Thirteen

Which one of the following cannot emit radiation and why? Excited nucleus, excited electron.

4 Views|Posted a year ago

Asked by Alok Kumar Singh

Answered by

Alok Kumar Singh | Contributor-Level 10

a year ago

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation- electron cannot emit radiation while exiting because they absorbs energy in eV which is very low as compared to gamma particle . as they contain energy in MeV

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New answer posted•a year ago

Nuclei Physics NCERT Exemplar Solutions Class 12th Chapter Thirteen