Assertion (A): | The density of the nucleus is much higher than that of ordinary matter. |
Reason (R): | \(10^5\) times smaller. | Most of the mass of the atom is concentrated in the nucleus while the size of this nucleus is almost
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | Both (A) and (R) are False. |
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
Assertion (A): | \(\beta^{-} \text-\) particles. | Radioactive nuclei emits
Reason (R): | Electrons exist inside the nucleus. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | (A) is False but (R) is True. |
Assertion (A): | Forces (nuclear) acting between proton-proton \((\mathrm{f}_{\mathrm{pp}})\), proton-neutron \((\mathrm{f}_{\mathrm{pn}})\) and neutron-neutron \((\mathrm{f}_{\mathrm{nn}})\) are such that \(\mathrm{f}_{\mathrm{pp}}<\mathrm{f}_{\mathrm{pn}}=\mathrm{f}_{\mathrm{nn}}\). |
Reason (R): | Electrostatic force of repulsion between two protons reduces nuclear forces between them. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | Both (A) and (R) are False. |
Assertion (A): | \(\beta\)-particles when they are emitted is higher than the mass of electrons obtained by other means. | The mass of
Reason (R): | \(\beta\)-particles and electrons, both are similar particles. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Assertion (A): | Electron capture occurs more than positron emission in a heavy nucleus. |
Reason (R): | In a heavy nucleus, electrons are relatively close to the nucleus. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Assertion (A): | All nuclei are not of the same size. |
Reason (R): | The size of the nucleus depends on atomic mass. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Assertion (A): | The ratio of time taken for light emission from an atom to that for the release of nuclear energy in fission is 1:100. |
Reason (R): | Time taken for the light emission from an atom is of the order of 10-8s. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Assertion (A): | 90Sr from radioactive fallout from a nuclear bomb ends up in the bones of human beings through the milk consumed by them. It causes impairment of the production of red blood cells. |
Reason (R): | \(\beta\)-particles emitted in the decay of 90Sr damage the bone marrow. | The energetic
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |