Q. No.A nucleus of uranium decays at rest into nuclei of thorium and helium. Then:
| 1. | The nucleus helium has more kinetic energy than the thorium nucleus |
| 2. | The helium nucleus has less momentum than the thorium nucleus |
| 3. | The helium nucleus has more momentum than the thorium nucleus |
| 4. | The helium nucleus has less kinetic energy than the thorium nucleus |
If the radius of \(_{13}^{27}\mathrm{Al}\) nucleus is taken to be \({R}_{\mathrm{Al}},\) then the radius of \(_{53}^{125}\mathrm{Te}\) nucleus is near:
| 1. | \(\left(\frac{53}{13}\right) ^{\frac{1}{3}}~{R_{Al}}\) | 2. | \(\frac{5}{3}~{R_{Al}}\) |
| 3. | \(\frac{3}{5}~{R_{Al}}\) | 4. | \(\left(\frac{13}{53}\right)~{R_{Al}}\) |
The Binding energy per nucleon of \(^{7}_{3}\mathrm{Li}\) and \(^{4}_{2}\mathrm{He}\) nucleon are \(5.60~\text{MeV}\) and \(7.06~\text{MeV}\), respectively. In the nuclear reaction \(^{7}_{3}\mathrm{Li} + ^{1}_{1}\mathrm{H} \rightarrow ^{4}_{2}\mathrm{He} + ^{4}_{2}\mathrm{He} +Q\), the value of energy \(Q\) released is:
1. \(19.6~\text{MeV}\)
2. \(-2.4~\text{MeV}\)
3. \(8.4~\text{MeV}\)
4. \(17.3~\text{MeV}\)
A radioisotope 'X' with a half-life 1.4 × 109 years decays to 'Y' which is stable. A sample of the rock from a cave was found to contain 'X' and 'Y' in the ratio 1:7. The age of the rock is:
1. 1.96 x 109 years
2. 3.92 x 109 years
3. 4.20 x 109 years
4. 8.40 x 109 years
(given \(1~\mathrm{u} = 931~\text{MeV}\) )
1. \(26.7~\text{MeV}\)
2. \(6.675~\text{MeV}\)
3. \(13.35~\text{MeV}\)
4. \(2.67~\text{MeV}\)
2. \(80\) years
3. \(100\) years
4. \(40\) years
| 1. | decrease continuously with mass number. |
| 2. | first decreases and then increases with an increase in mass number. |
| 3. | first increases and then decreases with an increase in mass number. |
| 4. | increases continuously with mass number. |
If the nuclear radius of \(^{27}\text{Al}\) is \(3.6\) Fermi, the approximate nuclear radius of \(^{64}\text{Cu}\) in Fermi is:
1. \(2.4\)
2. \(1.2\)
3. \(4.8\)
4. \(3.6\)
A mixture consists of two radioactive materials A1 and A2 with half-lives of 20 s and 10 s respectively. Initially, the mixture has 40 g of A1 and 160 g of A2. The amount of the two in the mixture will become equal after:
1. 60 s
2. 80 s
3. 20 s
4. 40 s
The half-life of a radioactive nucleus is 50 days. The time interval between the time when of it has decayed and the time when of it had decayed is:
1. 50 days
2. 60 days
3. 15 days
4. 30 days
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