What is the kinetic energy of the electron in an orbit of radius r in the hydrogen atom?
(e = electronic charge)

1. $\frac{k{e}^2}{r^2}$ 

2. $\frac{k{e}^2}{2r}$ 

3. $\frac{k{e}^2}{r}$ 

4. $\frac{k{e}^2}{2r^2}$

Ionisation potential of hydrogen atom is 13.6 eV. Hydrogen atoms in the ground state are excited by monochromatic radiation of photon energy 12.1 eV. According to Bohr's theory, the spectral lines emitted by hydrogen will be:

1. two 

2. three

3. four 

4. one

Orbital acceleration of electrons is:
1. \(\frac{n^2h^2}{4\pi^2m^2r^3}\)
2. \(\frac{n^2h^2}{4n^2r^3}\)
3. \(\frac{4n^2h^2}{\pi^2m^2r^3}\)
4. \(\frac{4n^2h^2}{4\pi^2m^2r^3}\)

Consider the spectral line resulting from transition \(n=2\) to \(n = 1\) in the atoms and ions given below.  The shortest wavelength is given by:

Out of the following which one is not a possible energy for a photon to be emitted by hydrogen atom according to Bohr's atomic model:

1. 13.6 eV

2. 0.65 eV

3. 1.9 eV

4. 11.1 eV

When a hydrogen atom is raised from the ground state to an excited state 

1. PE decreases and KE increases 

2. PE increases and KE decreases 

3. both KE PE decrease 

4. absorption spectrum

As per the Bohr model, the minimum energy (in eV) required to remove the electron from the ground state of a double ionised lithium ion (Z = 3) is:

1. 1.51

2. 13.6 

3. 40.8

4. 122.4

The ionisation energy of a hydrogen atom is 13.6 eV. Following Bohr's theory, what is the energy corresponding to a transition between the 3^rd and 4^th orbit?
1. 3.40 eV
2. 1.51 eV
3. 0.85 eV 
4. 0.66 eV

The ratio of the energies of the hydrogen atom in its first to second excited states is

1. $\frac{1}{4}$ 

2. $\frac{4}{9}$

3. $\frac{9}{4}$

4. 4

The velocity of the electron in the ground state (H - atom) is 

1. $2.18\times {10}^5 m/s$   

2. $2.18\times {10}^6 m/s$

3. $2.18\times {10}^7 m/s$   

4. $2.18\times {10}^8 m/s$