The energy equivalent of \(1\) g of substance is:
1. \(8.3\times10^{13}~\text{J}\)
2. \(9\times10^{13}~\text{J}\)
3. \(7.7\times10^{13}~\text{J}\)
4. \(11\times10^{13}~\text{J}\)
We are given the following atomic masses:
= 238.05079 u, = 4.00260 u
= 234.04363 u, = 1.00783 u
= 237.05121 u
Here the symbol Pa is for the element protactinium (Z = 91).
The energy released during the alpha decay of is:
1. 6.14 MeV
2. 7.68 MeV
3. 4.25 MeV
4. 5.01 MeV
We are given the following atomic masses:
= 238.05079 u, = 4.00260 u
= 234.04363 u, = 1.00783 u
= 237.05121 u
Here the symbol Pa is for the element protactinium (Z = 91).
Then:
1. can not spontaneously emit a proton.
2. can spontaneously emit a proton.
3. The Q-value of the process is negative.
4. Both (1) and (3)
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 half-life of undergoing -decay is years. What is the activity of the 1g sample of ?
1.
2.
3.
4.
Tritium has a half-life of 12.5 y undergoing beta decay. What fraction of a sample of pure tritium will remain undecayed after 25 y?
Which one of the following is incorrect?
1. | A chemical equation is balanced in the sense that the number of atoms of each element is the same on both sides of the equation. |
2. | The number of atoms of each element is not necessarily conserved in a nuclear reaction. |
3. | The number of protons and the number of neutrons are conserved in each nuclear reaction. |
4. | Mass-energy interconversion takes place only in nuclear reactions and never in the chemical reaction. |
Graph given below shows the variation of binding energy per nucleon, Ebn as a function of mass number. For nuclei with mass number A such that, 30 < A < 170, Ebn is almost constant because nuclear forces are:
1. Short-ranged
2. Medium-ranged
3. Long-ranged
4. None of the above
Graph gives the variation of potential energy of a pair of nucleons as a function of their separation, r. From the graph it can be concluded that the force between nucleons is attractive for distances:
1. Less than ro
2. Greater than ro
3. Less than
4. Less than
The graph shows the exponential decay of a radioactive specie. The number of nuclei decayed after time t is: