1. | is not important because nuclear forces are short-ranged |
2. | is as important as electrostatic force for binding the two atoms |
3. | cancels the repulsive electrostatic force between the nuclei |
4. | is not important because oxygen nucleus have equal number of neutrons and protons |
1. | \(M = m_{\text{proton}}+ m_{\text{electron}}.\) |
2. | \(M = m_{\text{proton}}+ m_{\text{electron}}-\frac{B}{c^2}\left(B= 13.6~\text{eV}\right)\). |
3. | \(M\) is not related to the mass of the hydrogen atom. |
4. | \(M = m_{\text{proton}}+ m_{\text{electron}}-\frac{|V|}{c^2}(|V|=\) magnitude of the potential energy of electron in the \(H\text-\)atom). |
1. | do not change for any type of radioactivity |
2. | change for \(\alpha\) and \(\beta\text-\)radioactivity but not for \(\gamma\text-\)radioactivity |
3. | change for \(\alpha\text-\)radioactivity but not for others |
4. | change for \(\beta\text-\)radioactivity but not for others |
1. | triton energy is less than that of a \(\mathrm{He}^{3}\) nucleus. |
2. | the electron created in the beta decay process cannot remain in the nucleus. |
3. | both the neutrons in Triton have to decay simultaneously resulting in a nucleus with \(3\) protons, which is not a \(\mathrm{He}^{3}\) nucleus. |
4. | free neutrons decay due to external perturbations which is absent in Triton nucleus. |
Mx and My denote the atomic masses of the parent and the daughter nuclei respectively in radioactive decay. The Q-value for a decay is Q1 and that for a decay is Q2. If denotes the mass of an electron, then which of the following statements is correct?
1.
2.
3.
4.
In a nuclear reactor, moderators slow down the neutrons which come out in a fission process. The moderator used have light nuclei. Heavy nuclei will not serve the purpose, because:
1. | they will break up |
2. | elastic collision of neutrons with heavy nuclei will not slow them down |
3. | the net weight of the reactor would be unbearably high |
4. | substances with heavy nuclei do not occur in the liquid or gaseous state at room temperature |
(a) | nuclear forces have short-range. |
(b) | nuclei are positively charged. |
(c) | the original nuclei must be completely ionized before fusion can take place. |
(d) | the original nuclei must first break up before combining with each other. |