A nucleus with mass number \(220\) initially at rest emits an \(\alpha\text-\)particle. If the \(Q\) value of the reaction is \(5.5\) MeV, then the kinetic energy of \(\alpha\text-\)particle is:
1. \(4.4\) meV
2. \(5.4\) MeV
3. \(5.6\) MeV
4. \(6.5\) MeV
The graph shows the variation of the number of radioactive atoms left undecayed with time. The time t corresponding to is:
1.
2.
3.
4.
The activity of a radioactive substance decays from 8000 becquerel to 4000 becquerel in 5 days. The activity of the substance after the next 10 days will be:
1. 500 becquerel
2. 1500 becquerel
3. 2000 becquerel
4. 1000 becquerel
A sample of radioactive material has initial mass A, decay constant B, molecular weight C and Avogadro's constant D. The activity of the sample after time, t, will be:
1.
2.
3.
4.
The statement which is incorrect about nuclear force between two protons is?
1. | These are always attractive forces. |
2. | These are non-central forces. |
3. | These are charge independent. |
4. | These are short-range forces. |
1. | \(\dfrac{8 A + 2}{A + 1}\) | 2. | \(\dfrac{8 A - 2}{A + 1}\) |
3. | \(\dfrac{8 A - 1}{A + 1}\) | 4. | \(\dfrac{8 A}{A + 1}\) |
1. | Decreases by \(4\) and mass number remains same. |
2. | Remains the same but the mass number increases by \(4\). |
3. | Remains the same but mass number decreases by \(8\). |
4. | Increases but mass number remains same. |
1. | Electron and antineutrino |
2. | Positron and antineutrino |
3. | Positron and neutrino |
4. | Electron and positron |