Considering Bohr's atomic model for hydrogen atom :
(A) the energy of H atom in ground state is same as energy of $He^+$ ion in its first excited state.
(B) the energy of H atom in ground state is same as that for $Li^{++}$ ion in its second excited state.
(C) the energy of H atom in ground state is same as that of $He^+$ ion for its ground state.
(D) the energy of $He^+$ ion in its first excited state is same as that for $Li^{++}$ ion in its ground state.
Choose the correct answer from the options given below :
The energy of an electron in the nth energy level of a hydrogen-like atom (atomic number Z) is given by Bohr's model:
$E_n = -13.6 \frac{Z^2}{n^2} \text{ eV}$
Where Z is the atomic number and n is the principal quantum number (n=1 for ground state, n=2 for first excited state, n=3 for second excited state).
Hydrogen atom (H): Z=1, n=1.
$E_{H, n=1} = -13.6 \frac{1^2}{1^2} \text{ eV} = -13.6 \text{ eV}$
$He^+$ ion: Z=2, n=2.
$E_{He^+, n=2} = -13.6 \frac{2^2}{2^2} \text{ eV} = -13.6 \text{ eV}$
Energies are equal. Statement (A) is TRUE.
Hydrogen atom (H): Z=1, n=1.
$E_{H, n=1} = -13.6 \text{ eV}$
$Li^{++}$ ion: Z=3, n=3.
$E_{Li^{++}}, n=3 = -13.6 \frac{3^2}{3^2} \text{ eV} = -13.6 \text{ eV}$
Statement (B) is FALSE.
Hydrogen atom (H): Z=1, n=1.
$E_{H, n=1} = -13.6 \text{ eV}$
$He^+$ ion: Z=2, n=1.
$E_{He^+, n=1} = -13.6 \frac{2^2}{1^2} \text{ eV} = -54.4 \text{ eV}$
Statement (C) is TRUE.
$He^+$ ion: Z=2, n=2.
$E_{He^+, n=2} = -13.6 \text{ eV}$
$Li^{++}$ ion: Z=3, n=1.
$E_{Li^{++}}, n=1 = -13.6 \frac{3^2}{1^2} \text{ eV} = -122.4 \text{ eV}$
Energies are not equal. Statement (D) is FALSE.
Statements (A) and (C) are TRUE. Statements (B) and (D) are FALSE.
This corresponds to Option 2: (A), (C) only.
Match the LIST-I with LIST-II
| LIST-I | LIST-II | ||
| A. | $^1_0n + ^{235}_{92}U \rightarrow ^{140}_{54}Xe + ^{94}_{38}Sr + 2^1_0n$ | I. | Chemical reaction |
| B. | $2H_2+O_2\rightarrow 2H_2O$ | II. | Fusion with +ve Q value |
| C. | $^1_1H+^2_1H \rightarrow ^3_2He + ^1_0n$ | III. | Fission |
| D. | $^1_1H+^1_1H \rightarrow ^2_1H+^0_1e$ | IV. | Fusion with -ve Q value |
Choose the correct answer from the options given below:
Choose the correct logic circuit for the given truth table having inputs A and B.
\[\begin{array}{|c|c|c|} \hline A & B & Y \\ \hline 0 & 0 & 0 \\ 0 & 1 & 0 \\ 1 & 0 & 1 \\ 1 & 1 & 1 \\ \hline \end{array}\]Two coherent monochromatic light beams of intensities 4I and 9I are superimposed. The difference between the maximum and minimum intensities in the resulting interference pattern is xI. The value of x is __________
A monochromatic light is incident on a metallic plate having work function $\phi$. An electron, emitted normally to the plate from a point A with maximum kinetic energy, enters a constant magnetic field, perpendicular to the initial velocity of electron. The electron passes through a curve and hits back the plate at a point B. The distance between A and B is:
(Given: The magnitude of charge of an electron is $e$ and mass is $m$, $h$ is Planck's constant and $c$ is velocity of light. Take the magnetic field exists throughout the path of electron)
Match the LIST-I with LIST-II
| LIST-I | LIST-II | ||
| A. | $^1_0n + ^{235}_{92}U \rightarrow ^{140}_{54}Xe + ^{94}_{38}Sr + 2^1_0n$ | I. | Chemical reaction |
| B. | $2H_2+O_2\rightarrow 2H_2O$ | II. | Fusion with +ve Q value |
| C. | $^1_1H+^2_1H \rightarrow ^3_2He + ^1_0n$ | III. | Fission |
| D. | $^1_1H+^1_1H \rightarrow ^2_1H+^0_1e$ | IV. | Fusion with -ve Q value |
Choose the correct answer from the options given below:
Choose the correct logic circuit for the given truth table having inputs A and B.
\[\begin{array}{|c|c|c|} \hline A & B & Y \\ \hline 0 & 0 & 0 \\ 0 & 1 & 0 \\ 1 & 0 & 1 \\ 1 & 1 & 1 \\ \hline \end{array}\]Two coherent monochromatic light beams of intensities 4I and 9I are superimposed. The difference between the maximum and minimum intensities in the resulting interference pattern is xI. The value of x is __________
A monochromatic light is incident on a metallic plate having work function $\phi$. An electron, emitted normally to the plate from a point A with maximum kinetic energy, enters a constant magnetic field, perpendicular to the initial velocity of electron. The electron passes through a curve and hits back the plate at a point B. The distance between A and B is:
(Given: The magnitude of charge of an electron is $e$ and mass is $m$, $h$ is Planck's constant and $c$ is velocity of light. Take the magnetic field exists throughout the path of electron)