Q. No.When a nucleus in an atom undergoes a radioactive decay, the electronic energy levels of the atom:
1.
do not change for any type of radioactivity
2.
change for α and β -radioactivity but not for γ -radioactivity
3.
change for α -radioactivity but not for others
4.
change for β -radioactivity but not for others
Tritium is an isotope of hydrogen whose nucleus triton contains 2 neutrons and 1 proton. Free neutrons decay into . If one of the neutrons in Triton decays, it would transform into He3 nucleus. This does not happen. This is because;
| 1. | triton energy is less than that of a He3 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 He3 nucleus. |
| 4. | free neutrons decay due to external perturbations which is absent in Triton nucleus |
The gravitational force between H-atom and another particle of mass m will be given by Newton's law \(F=\frac{GMm}{r^2},\) where r is
in km and
| 1. | M=mproton+melectron. |
| 2. | M=mproton+melectron-\(\frac{B}{c^2}\) ( B=13.6 eV ). |
| 3. | M is not related to the mass of the hydrogen atom. |
| 4. | M=mproton+melectron-\(\frac{|V|}{c^2}\) ( |V| = magnitude of the potential energy of electron in the H-atom). |
1. \(a+b+c\)
2. \(c+a-b\)
3. \(c-a-b\)
4. \(a+b-c\)
If in a nuclear fusion process. the masses of the fusing nuclei be \(m_1\) and \(m_2\) and the mass of the resultant nucleus be \(m_3,\) then:
| 1. | \( m_3=\left|m_1-m_2 \right|\) | 2. | \( m_3<\left ( m_1+m_2 \right ) \) |
| 3. | \( m_3>\left ( m_1+m_2 \right ) \) | 4. | \( m_3=\left ( m_1+m_2 \right ) \) |
A nucleus represented by the symbol has:
| 1. | Z protons and A –Z neutrons |
| 2. | Z protons and A neutrons |
| 3. | A protons and Z –A neutrons |
| 4. | Z neutrons and A –Z protons |
Solar energy is mainly caused due to:
| 1. | burning of hydrogen in the oxygen |
| 2. | fission of uranium present in the sun |
| 3. | fusion of protons during synthesis of heavier elements |
| 4. | gravitational contraction |
The volume occupied by an atom is greater than the volume of the nucleus by a factor of about:
1. \(10\)
2. \(10^5\)
3. \(10^{10}\)
4. \(10^{15}\)
The energy required in \(\mathrm{MeV} / \mathrm{c}^2\) to separate \({ }_8^{16} \mathrm{O}\) into its constituents is:
(Given mass defect for \({ }_8^{16} \mathrm{O}=0.13691 \mathrm{u}\))
1. \(127.5\)
2. \(120.0\)
3. \(222.0\)
4. \(119.0\)
The energy equivalent of \(0.5\) g of a substance is:
1. \(4.5\times10^{13}\) J
2. \(1.5\times10^{13}\) J
3. \(0.5\times10^{13}\) J
4. \(4.5\times10^{16}\) J
© 2024 GoodEd Technologies Pvt. Ltd.