Q. No.If an alpha nucleus of energy bombards a heavy nuclear target of charge Ze, then the distance of closest approach for the alpha nucleus will be proportional to:
1.
\(\frac{1}{Ze} \)
2.
\(v^2 \)
3.
\(\frac{1}{m} \)
4.
\(\frac{1}{v^4}\)
The ratio of the longest wavelengths corresponding to the Lyman and Balmer series in the hydrogen spectrum is:
| 1. | \(\frac{3}{23}\) | 2. | \(\frac{7}{29}\) |
| 3. | \(\frac{9}{31}\) | 4. | \(\frac{5}{27}\) |
Given that the value of the Rydberg constant is \(10^{7}~\text{m}^{-1}\), what will be the wave number of the last line of the Balmer series in the hydrogen spectrum?
1. \(0.5 \times 10^{7}~\text{m}^{-1}\)
2. \(0.25 \times 10^{7} ~\text{m}^{-1}\)
3. \(2.5 \times 10^{7}~\text{m}^{-1}\)
4. \(0.025 \times 10^{4} ~\text{m}^{-1}\)
An electron revolves around a nucleus of charge Ze. In order to excite the electron from the state n=3 to n=4, the energy required is 66.0 eV. The value of Z will be:
1. 25
2. 10
3. 4
4. 5
How much is the total energy of an electron in the first orbit of a hydrogen atom equal to?
| 1. | total energy of electron in 1st orbit of \(\mathrm{He}^{+}\) |
| 2. | total energy of electron in 3rd orbit of \(\mathrm{He}^{+}\) |
| 3. | total energy of electron in 2nd orbit of \(\mathrm{Li}^{++}\) |
| 4. | total energy of electron in 3rd orbit of \(\mathrm{Li}^{++}\) |
What is the ratio of the circumference of the first Bohr orbit for the electron in the hydrogen atom to the de-Broglie wavelength of electrons having the same velocity as the electron in the first Bohr orbit of the hydrogen atom?
1. 1:1
2. 1:2
3. 1:4
4. 2:1
In Bohr's model if the atomic radius of the first orbit is r0, then what will be the radius of the third orbit?
1.
2.
3.
4.
When a hydrogen atom is raised from the ground state to an excited state:
| 1. | its P.E. increases and K.E. decreases. |
| 2. | its P.E. decreases and K.E. increases. |
| 3. | both kinetic energy and potential energy increase. |
| 4. | both K.E. and P.E. decrease. |
A beam of fast-moving alpha particles were 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 maximum and in B' minimum |
| 3. | A' will be minimum and in B' maximum |
| 4. | C' will be minimum and in B' maximum |
In the nth orbit, the energy of an electron is \(\mathrm{E}_{\mathrm{n}}=-\frac{13.6}{\mathrm{n}^2} \mathrm{~eV}\) for the hydrogen atom. What will be the energy required to take the electron from the first orbit to the second orbit?
1. 10.2 eV
2. 12.1 eV
3. 13.6 eV
4. 3.4 eV
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