Q. No.Maximum frequency of emission is obtained for the transition:
1. n = 2 to n = 1
2. n = 6 to n = 2
3. n = 1 to n = 2
4. n = 2 to n = 6
The total energy of an electron in the first excited state of a hydrogen atom is about \(-3.4~\text{eV}.\) Its kinetic energy in this state will be:
1. \(-6.8~\text{eV}\)
2. \(3.4~\text{eV}\)
3. \(6.8~\text{eV}\)
4. \(-3.4~\text{eV}\)
Energy levels A, B and C of a certain atom correspond to increasing values of energy i.e. \(E_A<E_B<E_C\). If \(\lambda_1, ~\lambda_2\) and \(\lambda_3\) are wavelengths of radiations corresponding to transitions C to B, B to A and C to A respectively, which of the following relations is correct?
1. \(\lambda_3=\lambda_1+\lambda_2\)
2. \(\lambda_1+\lambda_2+\lambda_3=0\)
3. \(\lambda_3^2=\lambda_1^2+\lambda_2^2\)
4. \(\lambda_3=\frac{\lambda_1 \lambda_2}{\lambda_1+\lambda_2}\)
1. \(\frac{e}{\sqrt{4\pi m\varepsilon_0 r}}\)
2. \(\frac{2e}{\sqrt{\pi m\varepsilon_0 r}}\)
3. \(\frac{e}{\sqrt{\pi m\varepsilon_0 r}}\)
4. \(\frac{e}{4\pi m\varepsilon_0 r}\)
| 1. | the first line of the Lyman series. |
| 2. | the second line of the Balmer series. |
| 3. | the first line of the Paschen series. |
| 4. | the second line of the Paschen series. |
Energy \(E\) of a hydrogen atom with principal quantum number \(n\) is given by \(E=-\frac{13.6}{n^{2}}~\text{eV}.\) The energy of a photon ejected when the electron jumps from \(n=3\) state to \(n=2\) state of hydrogen is approximately:
1. \(0.85~\text{eV}\)
2. \(3.4~\text{eV}\)
3. \(1.9~\text{eV}\)
4. \(1.5~\text{eV}\)
| 1. | uses Einstein's photoelectric equation. |
| 2. | predicts continuous emission spectra for atoms. |
| 3. | predicts the same emission spectra for all types of atoms. |
| 4. | assumes that the angular momentum of electrons is quantized. |
1. \(K \frac{e^{2}}{r^{2}} \hat{r}\)
2. \(- K \frac{e^{2}}{r^{3}} \hat{r}\)
3. \(K \frac{e^{2}}{r^{3}} \overset{\rightarrow}{r}\)
4. \(- K \frac{e^{2}}{r^{3}} \overset{\rightarrow}{r}\)
| 1. | \(4E_n\) | 2. | \(\dfrac{E_n}{4}\) |
| 3. | \(2E_n\) | 4. | \(\dfrac{E_n}{2}\) |
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