321.

The wavelength of a spectral line emitted by hydrogen atom in the Lyman series is $\frac{16}{15\mathrm{R}}\mathrm{cm}$.
The value of n, will be

                               [R=Rydberg constant]

• 1

• 2

• 3

• 4

Which of the following have maximum number of unpaired electrons ?

• Fe³⁺

• Fe²⁺

• Co²⁺

• Co³⁺

If magnetic quantum number of a given atom represented by -3, then what will be its principal quantum number ?

• 2

• 3

• 4

• 5

For an electron whose x-positional uncertainity is 1x 10^-10 m, the uncertainity in the x-component of the velocity in ms^-1 will be of the order of:

$(\mathrm{Data} : {\mathrm{m}}_{\mathrm{e}} = 9\times {10}^{-31} \mathrm{Kg} , \mathrm{h}= 6.6 \times 10{ }^{-34} \mathrm{JS} )$

• 10⁶

• 10³

• 10¹²

• 10¹⁵

Total number of atoms represented by the compound CuSO₄ · 5H₂O is :

• 27

• 21

• 5

• 8

When electrons are trapped into the crystal in anion vacancy, the defect is known as :

• Schottky defect

• Frenkel defect

• stoichiometric defect

• F-centres

The correct sets of quantum numbers which represents the highest energy level in an atomis:

• $\mathrm{n}=4 , \mathrm{l}=0 , \mathrm{m}=0 , \mathrm{s} = + \frac{1}{2}$

• $\mathrm{n}=3 , \mathrm{l}=0 , \mathrm{m}=0 , \mathrm{s} = + \frac{1}{2}$

• $\mathrm{n}=3 , \mathrm{l}=1 , \mathrm{m}=1 , \mathrm{s} = + \frac{1}{2}$

• $\mathrm{n}=3 , \mathrm{l}=2 , \mathrm{m}= -1 , \mathrm{s} = + \frac{1}{2}$

Wave number of a spectral line for a given transition is xcm^-1 for He⁺ then its value for Be⁺ (iso electronic of H⁺) for same transition is:

• x cm^-1

• 4x cm^-1

• $\frac{\mathrm{x}}{4}$cm^-1

• 2x cm^-1

Ratio of radii of second and first Bohr orbits of H atom is

• 2

• 4

• 3

• 5

India conducted an underground nuclear test at

• Narora

• Tarapur

• Pushkar

• Pokharan