What happens whenever a hydrogen atom emits a photon in the Balmer series?

1.	it may emit another photon in the Balmer series.
2.	it must emit another photon in the Lyman series.
3.	it may emit another photon in the Paschen series.
4.	it need not emit any more photon.

The ionisation potential of hydrogen atom is

1. 13.60 volt

2. 8.24 volt

3. 10.36 volt 

4. 14.24 bolt

Which source is associated with a line emission spectrum? 

1. Electric fibre 

2. Neon street Sign

3. Red traffic light 

4. Sun

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

The frequency of the series limit of the Balmer series of hydrogen atoms in terms of Rydberg constant R and velocity of light C is:

1. $\frac{RC}{4}$

2. RC

3. $\frac{4}{RC}$

4. 4RC

Orbital acceleration of electron is 

1. $\frac{n^2{h}^2}{4{\mathrm{\pi }}^2{\mathrm{m}}^2{\mathrm{r}}^3}$   

2. $\frac{n^2{h}^2}{4n^2{\mathrm{r}}^3}$

3. $\frac{4n^2{h}^2}{{\mathrm{\pi }}^2{\mathrm{m}}^2{\mathrm{r}}^3}$ 

4. $\frac{4n^2{h}^2}{4{\mathrm{\pi }}^2{\mathrm{m}}^2{\mathrm{r}}^3}$

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:
1. hydrogen atom
2. deuterium
3. singly ionised helium
4. doubly ionised lithium

An $\alpha -$particle of energy 5 MeV is scattered through $180°$ by a fixed uranium nucleus. The distance of closest approach is of the order

1. ${10}^{-10} m$ 

2. ${10}^{-13} m$ 

3. ${10}^{-14} m$ 

4. ${10}^{-16} m$

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

The energy of an electron in an excited hydrogen atom is -3.4 eV.  Its angular momentum will be:
(h = 6.626 $\times$ 10^-34 J-s)

1. 1.11 $\times$ 10³⁴ J s 

2. 1.51 $\times$10^-31 J s

3. 2.11 $\times$ 10^-34 J s

4. 3.72 $\times$ 10^-34 J s