Q. No.What happens to the mass number and the atomic number of an element when it emits \(\gamma\text{-}\)radiation?
1.
mass number decreases by four and atomic number decreases by two.
2.
mass number and atomic number remain unchanged.
3.
mass number remains unchanged while the atomic number decreases by one.
4.
mass number increases by four and the atomic number increases by two.
The binding energy per nucleon in deuterium and helium nuclei are \(1.1\) MeV and \(7.0\) MeV, respectively. When two deuterium nuclei fuse to form a helium nucleus the energy released in the fusion is:
1. \(2.2\) MeV
2. \(28.0\) MeV
3. \(30.2\) MeV
4. \(23.6\) MeV
\({}_{92}^{235}\mathrm{U}+ {}_{0}^{1}\mathrm{n}\rightarrow {}_{56}^{144}\mathrm{Ba}+...+3{}_{0}^{1}\mathrm{n}\)
The blank space can be filled by:
| 1. | \({}_{26}^{89}\mathrm{Kr}\) | 2. | \({}_{36}^{89}\mathrm{Kr}\) |
| 3. | \({}_{26}^{90}\mathrm{Sr}\) | 4. | \({}_{38}^{89}\mathrm{Sr}\) |
| 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 |
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. \(10^{15}\)
| (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. |
Choose the correct option:
| 1. | (a) and (c) | 2. | (a) and (d) |
| 3. | (b) and (d) | 4. | (a) and (b) |
If the mass of the iron nucleus is \(55.85~\text{u}\) and \(\mathrm{A} = 56\), the nuclear density of the iron is:
| 1. | \(2.27\times10^{17}~\text{kg m}^{-3}\) |
| 2. | \(1.36\times 10^{15}~\text{kg m}^{-3}\) |
| 3. | \(3.09\times10^{17}~\text{kg m}^{-3}\) |
| 4. | \(4.11\times10^{15}~\text{kg m}^{-3}\) |
The energy required in \(\text{MeV/c}^2 \) to separate \({ }_8^{16} \mathrm{O}\) into its constituents is:
(Given: mass defect for \({ }_8^{16} \mathrm{O}=0.13691~ \text{amu}\))
| 1. | \(127.5\) | 2. | \(120.0\) |
| 3. | \(222.0\) | 4. | \(119.0\) |
A nucleus with mass number \(240\) breaks into fragments each of mass number \(120.\) The binding energy per nucleon of unfragmented nuclei is \(7.6~\text{MeV}\) while that of fragments is \(8.5~\text{MeV}.\) The total gain in the binding energy in the process is:
| 1. | \(804~\text{MeV}\) | 2. | \(216~\text{MeV}\) |
| 3. | \(0.9~\text{MeV}\) | 4. | \(9.4~\text{MeV}\) |
| 1. | \(\beta^{+}, ~\alpha, ~\beta^{-}\) | 2. | \(\beta^{-}, ~\alpha, ~\beta^{+}\) |
| 3. | \(\alpha, ~\beta^{-},~\beta^{+}\) | 4. | \(\alpha, ~\beta^{+},~\beta^{-}\) |
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