Assertion (A): | The hydrogen atom consists of only one electron but its emission spectrum has many lines. |
Reason (R): | Only Lyman series is found in the absorption spectrum of hydrogen atoms whereas in the emission spectrum, all the series are found. |
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 Balmer series lies in the visible region of the electromagnetic spectrum. |
Reason (R): | \(\frac{1}{\lambda}={R}\left[\frac{1}{2^{2}}-\frac{1}{n^{2}}\right], \text { where } n=3,4,5.\) |
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): | LASER is used to measure distant objects as moon. |
Reason (R): | They are highly coherent sources of light. |
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): | In He-Ne laser, population inversion takes place between energy levels of neon atoms. |
Reason (R): | Helium atoms have a meta-stable energy level. |
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. |
The Balmer series for the H-atom can be observed:
a. | if we measure the frequencies of light emitted when an excited atom falls to the ground state |
b. | if we measure the frequencies of light emitted due to transitions between excited states and the first excited state |
c. | in any transition in a H-atom |
d. | as a sequence of frequencies with the higher frequencies getting closely packed |
1. (b, c)
2. (a, c)
3. (b, d)
4. (c, d)
Assertion (A): | When light consisting of wavelengths corresponding to the Balmer series is incident on a gas containing \(\mathrm{He}^{+}\) ions in the first three excited states - it can be absorbed by the \(\mathrm{He}^{+}\) ions. |
Reason (R): | All the energy levels of the \(\mathrm{He}^{+}\) ions are the same as those of the \(\mathrm{H}\) atoms. |
1. | (A) is True but (R) is False. |
2. | (A) is False but (R) is True. |
3. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
4. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |