Q. No.A beam of fast-moving alpha particles was directed towards a thin film of gold. The parts \(A', B',\) and \(C'\) of the transmitted and reflected beams corresponding to the incident parts \(A,B\) and \(C\) of the beam, are shown in the adjoining diagram. The number of alpha particles in:
| 1. | \(B'\) will be minimum and in \(C'\) maximum |
| 2. | \(A'\) will be the maximum and in \(B'\) minimum |
| 3. | \(A'\) will be minimum and in \(B'\) maximum |
| 4. | \(C'\) will be minimum and in \(B'\) maximum |
| 1. | \(\frac{1}{Ze} \) | 2. | \(v^2 \) |
| 3. | \(\frac{1}{m} \) | 4. | \(\frac{1}{v^4}\) |
The Rutherford \(α -\)particle experiment shows that most of the \(α -\)particles pass through almost unscattered while some are scattered through large angles. What information does it give about the structure of the atom?
| 1. | The atom is hollow. |
| 2. | The whole mass of the atom is concentrated in a small center called the nucleus. |
| 3. | The nucleus is positively charged. |
| 4. | All of the above |
| Statement I: | The scattering of α-particles at large angles is primarily due to the atomic nucleus. |
| Statement II: | The atomic nucleus is very heavy in comparison to electrons. |
| 1. | Statement I is correct and Statement II is incorrect. |
| 2. | Statement I is incorrect and Statement II is correct. |
| 3. | Both Statement I and Statement II are correct. |
| 4. | Both Statement I and Statement II are incorrect. |
Which statement about the Rutherford model of the atom is not true?
| 1. | There is a positively charged centre in an atom called the nucleus. |
| 2. | Nearly all the mass of an atom resides in the nucleus. |
| 3. | The size of the nucleus is the same as that of the atom. |
| 4. | Electrons occupy the space surrounding the nucleus. |
| Assertion (A): | The positively charged nucleus of an atom has a radius of almost \(10^{-15}~\text{m}\). |
| Reason (R): | In \(\alpha\)-particle scattering experiment, the distance of the closest approach for \(\alpha\)-particle is \(\approx 10^{-15}~\text m\). |
| 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. |
It is found experimentally that \(13.6~\text{eV}\) energy is required to separate a hydrogen atom into a proton and an electron. The velocity of the electron in a hydrogen atom is:
1. \(3.2\times10^6~\text{m/s}\)
2. \(2.2\times10^6~\text{m/s}\)
3. \(3.2\times10^6~\text{m/s}\)
4. \(1.2\times10^6~\text{m/s}\)
Which of the following curves represents the variation in the number of \(\alpha \text-\)particles scattered \((N)\) with the scattering angle \((\theta)\) in Rutherford's \(\alpha \text-\)particle scattering experiment?
| 1. |  |
2. |  |
| 3. |  |
4. |  |
In \(1911\), the physician Ernest Rutherford discovered that atoms have a tiny, dense nucleus by shooting positively charged particles at a very thin gold foil. A key physical property that led Rutherford to use gold was that it was:
1. electrically conducting
2. highly malleable
3. shiny
4. non-reactive
The ratio of momenta of an electron and an \(\alpha \text-\)particle which are accelerated from rest by a potential difference of \(100~\text{V}\) is:
1. \(1\)
2. \(\sqrt{\frac{2m_e}{m_{\alpha}}}\)
3. \(\sqrt{\frac{m_e}{m_{\alpha}}}\)
4. \(\sqrt{\frac{m_e}{2m_{\alpha}}}\)
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