Revision Notes for CBSE Class 12 Physics Chapter 13 (Nuclei) - Free PDF Download
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FAQs on Nuclei Class 12 Notes CBSE Physics Chapter 13 (Free PDF Download)
1. What is a Nuclei?
It is defined as the collection of particles of protons which are positively charged and electrically neutral neutrons. Neutrons and protons are intern made up of quarks particles.
2. Which topics are included in Nuclear Physics?
The topics includes the nuclear weapons, nuclear power, medicine, magnetic imaging resonance, ions implantation, engineering, cultural and industrial isotope, in geology radiocarbon dating, in the nuclear engineering field such are used.
3. What is the function of the Nuclei?
The function of the nuclei is defined as to control gene expression and during the cell cycle they do the replication of DNA. The energy of nuclei is very huge and it can be used in nuclear power plants.
4. What do we mean by Nuclei?
Nuclei is the latin word which is described as the seed inside a fruit. To the atomic nucleus it is referred to and is the dense central region of the atom.
5. Explain the order of Radioactivity Decay of the Unstable Nuclei.
The loss of elementary particles from the unstable nucleus which changes the unstable elements into more stable ones is defined as the radioactivity decay. They are of five types namely: beta, alpha, gamma, piston electron and electron capture.
6. If both the number of protons and neutrons in a nuclear reaction is conserved, in what way is mass converted into energy (or vice versa)?
Since the number of protons and neutrons are unchanged in this nuclear reaction, the whole rest mass of protons and neutrons remains the same on both sides of this nuclear reaction. However, the total binding energy in the nuclei on the left-hand side does not necessarily have to be the same as on the right side. This difference in the binding energy results in the release of energy through the reaction. For a thorough understanding of the subject, visit the page NCERT Notes for Class 12 Physics.
7. Why is heavy water generally used as a moderator in a nuclear reactor?
Neutrons produced while fission will slow down if they strike a nucleus of equal mass. Because ordinary water is made of hydrogen atoms with a mass very close to the neutrons, so it may be used as the moderator. However, it will absorb neutrons at a very fast rate with the reaction;
n+p —» d+y
Here, d refers to the deuteron. In order to overcome such a difficulty, heavy water has to be used as the moderator that has little to no cross-section for absorption of neutrons. For a complete explanation of the chapter, visit the page NCERT Notes for Class 12 Physics.
8. The mass of a nucleus in its ground state is always less than the total mass of its constituents – neutrons and protons. Explain.
If nucleons approach one another to form a nucleus, they strongly attract each other. Their potential energy decreases and becomes negative. This potential energy holds together the nucleons in the nucleus. A decrease in the potential energy thus results in a decrease in the mass of the nucleon inside the nucleus as well. For more explanation and study materials regarding the chapter, students can download the vedantu app.
9. Can it be concluded from beta decay that electrons exist inside the nucleus?
No, although an electron, the beta particle is in fact created in the moment of beta decay, and also ejected right then. It will not be able to exist within the nucleus because of the de-Broglie wavelength that is significantly larger than the size of the nucleus. To know more students can visit the page NCERT Notes for Class 12 Physics and download the revision notes free of cost.
10. Why do stable nuclei never have more protons than neutrons?
Protons are parts of the atom that are positively charged, which means they electrically repel one another. This repulsion increases too much in the nuclei in case of greater than 10 protons. Therefore a greater amount of neutrons, that produce just the attractive forces, is mandatory for stability.