The energy and the radius of the first orbit of He+ are respectively :
1. \(-8.72\times 10^{-18}J\); 0.02645 nm
2. \(8.72\times 10^{-18}J\); 0.02645 nm
3. \(-7.82\times 10^{-18}J\) ; 0.03655 nm
4. \(7.82\times 10^{-18}J\); 0.03655 nm
A ball weighing 10 g is moving with a velocity of 90 ms–1. If the uncertainty in its velocity is 5 %, then the uncertainty in its position is X × 10–33 m. The value of X will be :
[Given : h = 6.63 × 10–34 Js]
1. 1.17
2. 1.37
3. 1.67
4. 1.97
When electromagnetic radiation of wavelength 300 nm falls on the surface of sodium, electrons are emitted with a kinetic energy of 1.68 ×105 J mol–1. The minimum energy needed to remove an electron from sodium and the maximum wavelength that will cause a photoelectron to be emitted are, respectively:
1. 2.31 × 105 J mol–1, 517 nm
2. 23.1 × 105 J mol–1, 517 nm
3. 3.31 × 105 J mol–1, 417 nm
4. 33.1 × 105 J mol–1, 417 nm
The number of electrons, protons and neutrons in a species are equal to 18, 16 and 16 respectively. The proper symbol of the species is :
1. | \(_{16}^{32}S^{2-}\) | 2. | \(_{18}^{32}S^{2-}\) |
3. | 4. |
The radius of a hydrogen shell is 0.53Å. In its first excited state, radius of the shell will be:
1. 2.12 Å
2. 1.06 Å
3. 8.5 Å
4. 4.24 Å
If the energy of the second Bohr orbit of the hydrogen atom is –328 kJ mol–1, the energy of the fourth Bohr orbit would be:
1. | –1312 kJ mol–1 | 2. | –82 kJ mol–1 |
3. | –41 kJ mol–1 | 4. | –164 kJ mol–1 |
A 0.66 kg ball is moving with a speed of 100 m/s. The associated wavelength will be:
1.
2.
3.
4.
Match the following:
Column I | Column II | ||
A. | X-rays | 1. | |
B. | Ultraviolet wave (UV) | 2. | |
C. | Long radio waves | 3. | |
D. | Microwave | 4. |
A | B | C | D | |
1. | 4 | 1 | 3 | 2 |
2. | 1 | 4 | 2 | 3 |
3. | 1 | 4 | 3 | 2 |
4. | 4 | 3 | 1 | 2 |
Match the ensuing rules with the corresponding statements:
Rules | Statements | ||
A. | Hund’s Rule | 1. | No two electrons in an atom can have the same set of four quantum numbers. |
B. | Aufbau Principle | 2. | Half-filled and completely filled orbitals have extra stability. |
C. | Pauli's Exclusion Principle | 3. | Pairing of electrons in the orbitals belonging to the same subshell does not take place until each orbital is singly occupied. |
D. | Heisenberg’s Uncertainty Principle | 4. | It is impossible to determine the exact position and exact momentum of a subatomic particle simultaneously. |
5. | In the ground state of atoms, orbitals are filled in the order of their increasing energies. |
A | B | C | D | |
1. | 3 | 5 | 1 | 2 |
2. | 1 | 2 | 3 | 4 |
3. | 3 | 5 | 1 | 4 |
4. | 4 | 5 | 3 | 2 |