In a subshell, if the number of radial nodes is two times the number of angular nodes, then the minimum possible value of the principal quantum number (n) is: 

[angular nodes are non-zero)

1.	1	2.	2
3.	3	4.	4

The wavelength of a certain line in the Balmer series is observed to be 4341 A^o for hydrogen atoms.
The electronic transition among the following may be:

1. 3 → 2
2. 4 → 1
3. 5 → 2
4. 5 → 3

The charge on the electron and proton are reduced to $\frac{2}{3}\mathrm{rd}$ of their original values. Let the present value of the Rydberg constant of H-atom be R, then the new value of the Rydberg constant will be

$1. \frac{2\mathrm{R}}{3}$
$2. \frac{4\mathrm{R}}{9}$
$3. \frac{8\mathrm{R}}{27}$
$4. \frac{16\mathrm{R}}{81}$

The wavelength of the spectral line obtained in the spectrum of ${\mathrm{Li}}^{+2}$
when the transition takes place between levels whose sum is 4 and the difference is 2, will be:

1.  11.4 x ${10}^{-6}$ cm

2.  1.14 x ${10}^{-6}$cm

3.  0.114 x ${10}^{-6}$ cm

4.  1.14 x ${10}^{-8}$ cm

In the transition of an electron in an atom, its kinetic energy changes from y to $\frac{y}{4}$. The change in potential energy will be -

1. \(\frac{-3}{8} y\)
2. \({{3}\over{2}}y\)
3. \({{3}\over{4}}y\)
4. \(-{{3}\over{4}}y\)

A photon with an initial frequency of \(10^{11}~\mathrm{Hz}\) scatters off an electron at rest. Its final frequency is \(0.9 \times10^{11}~\mathrm{Hz}.\) The speed of scattered electron is close to: 

Photons of wavelength 4000  $A^o$ are used to break ${\mathrm{l}}_2$ molecules. The percentage of energy converted to the kinetic energy of atoms will be :

(bond dissociation energy of the molecule is 246.5 kJ/mol)

1.  12%

2.  8%

3.  26%

4.  17%

The number of unpaired electrons in 1s² 2s² 2p³ is -

1. 2

2. 0

3. 3

4. 1

${\mathrm{Be}}^{3+}$ion and a proton are accelerated by the same potential. The ratio of their de-Broglie wavelengths is

(assume mass of proton =  mass of neutron)

1. 1:2

2. 1:4

3. 1:1

4. 1:$3\sqrt{3}$