Bohr's Model of a Hydrogen Atom

Q. The ratio of the energy of electrons in $1^{\text{st}}$ shell of $H{e}^{+}$ and $3^{\text{rd}}$ shell of $L{i}^{+2}$ is

Q.

Select the correct statement(s):

1. An electron near the nucleus is attracted by the nucleus and has a low potential energy

2. According to Bohr's theory, an electron orbit
3. Bohr's model could not explain the spectra of multi-electron atoms
4. Bohr's model was the first atomic model based on quantization of energy

Q. Bohr’s theory explains atomic spectrum of

1. $H{e}^{+}$
2. $L{i}^{2+}$
3. $B{e}^{3+}$
4. $Allofthese$

Q.

If the shortest wave - length of a spectral line in Lyman series for $H{e}^{+}$ is 'x', then what will be the largest wave length of a spectral line in Balmer series of $L{i}^{2+}$

1. $\frac{4x}{5}$

2. $\frac{5x}{4}$

3. $9x$

4. $\frac{16x}{5}$

Q.

Energy levels, A, B, C, of a certain atom correspond to increasing values of energy i.e., $E_A<E_B<E_C$ If ${\lambda }_1,{\lambda }_2,{\lambda }_3$ are the wave lengths of radiations corresponding to the transition from C to B, B to A and C to A respectively, which of the following statements is correct ?

1. ${\lambda }_3=\frac{{\lambda }_1{\lambda }_2}{{\lambda }_1+{\lambda }_2}$

2. ${\lambda }_1+{\lambda }_2+{\lambda }_3=0$
   

3. ${\lambda }_3^2={\lambda }_1^2+{\lambda }_2^2$

4. ${\lambda }_3={\lambda }_1+{\lambda }_2$

Q.

The given diagram indicates the energy levels of certain atoms. When the system moves from the 2E level to E a photon of wavelength $\lambda$ is emitted. The wavelength of photon produced during its transition from $\frac{4E}{3}$ level to E is

1. $\frac{\lambda }{3}$

2. $\frac{3\lambda }{3}$

3. $\frac{4}{3}\lambda$

4. $3\lambda$

Q.

Which of the following gives the correct ratio between time periods of an electron for each revolution in second and third Bohr's orbits ?

1. 9 : 4

2. 8 : 27

3. 27 : 8

4. 4 : 9

Q.

The energy of an electron in the first Bohr orbit of H - atom is - 13.6 eV. Then, which of the following statement(s) is/are correct for $H{e}^{+}$ ?

1. The energy of electron in second Bohr orbit is -13.6eV

2. The kinetic energy of electron in the first orbit is 54.46 eV

3. The kinetic energy of electron in the second orbit is 13.6 eV

4. The speed of electron in the second orbit is $2.19\times {10}^{6}m{s}^1$

Q.

When an electron jumps from 4^th orbit to 1^storbit, it emits a radiation whose spectral line corresponds to:

1. Lyman series

2. Balmer series

3. Pfund series

4. Paschen series

Q.

According to Bohr's theory

1. When a required amount of energy is supplied to an electron in an atom it jumps from lower orbit to higher orbit and remains there

2. When a required amount of energy is supplied to an electron in an atom it jumps from lower orbit to higher orbit and remains there for very short interval of time and returns back to lower orbit, radiating energy

3. The angular momentum of an electron is proportional to its quantum number, n

4. The angular momentum of an electron is independent to its quantum number, n