
1. \(2000~\mathring{A}\)
2. \(4000~\mathring{A}\)
3. \(4500~\mathring{A}\)
4. \(9000~\mathring{A}\)
| 1. | \(5\rightarrow 4\) | 2. | \(3\rightarrow 2\) |
| 3. | \(2\rightarrow 1\) | 4. | \(3\rightarrow 1\) |
| 1. | ![]() |
2. | ![]() |
| 3. | ![]() |
4. | ![]() |
| 1. | \(145\) | 2. | \(160\) |
| 3. | \(172\) | 4. | \(157\) |
The de-Broglie wavelength of an electron in the second orbit of a hydrogen atom is equal to:
| 1. | The perimeter of the orbit. |
| 2. | The half of the perimeter of the orbit. |
| 3. | The half of the diameter of the orbit. |
| 4. | The diameter of the orbit. |
What is the ratio of the speed of an electron in the first orbit of an \(\mathrm{H}\text-\)atom to the speed of light?
| 1. | \(\dfrac{1}{137}\) | 2. | \(137\) |
| 3. | \(\dfrac{1}{83}\) | 4. | \(\dfrac{1}{47}\) |
What happens when an electron makes a transition from an excited state to the ground state of a hydrogen-like atom or ion?
| 1. | Its kinetic energy increases but potential energy and total energy decrease. |
| 2. | Kinetic energy, potential energy and total energy decrease. |
| 3. | Kinetic energy decreases, potential energy increases but the total energy remains the same. |
| 4. | Kinetic energy and total energy decrease but potential energy increases. |
The wavelength of the first line of the Lyman series for a hydrogen atom is equal to that of the second line of the Balmer series for a hydrogen-like ion. What is the atomic number \(Z\) of hydrogen-like ions?
1. \(4\)
2. \(1\)
3. \(2\)
4. \(3\)