Which type of radiation is not emitted by the electronic structure of atoms:

1. Ultraviolet light

2. X-rays

3. Visible light

4. y-rays

An absorption line of the lowest frequency in the transition of hydrogen spectra is:

1. n=1 to n=2

2. n=3 to n=8

3. n=2 to n=1

4. n=8 to n=3

The maximum number of atomic orbitals associated with a principal quantum number 5 is-

1. 9

2. 12

3. 16

4. 25

The de-Broglie wavelength of a particle having the momentum of
3.3 x 10^-24 kg m s^-1 will be;

1. 0.002 Å

2. 0.02 Å

3. 0.2 Å

4. 2Å

The quantum number of the most energetic electron in an Ne atom in the first excited state is

The total number of neutrons in dipositive zinc ions with mass number 70 is -

1. 34

2. 40

3. 36

4. 38

With a certain exciting radiation of a particular frequency, to which hydrogen atoms are exposed, the maximum number of spectral lines obtainable in the emission is 15. The uppermost energy level to which the electron is excited is 

1. 4

2. 5

3. 6

4. 7

When accelerated electrons are direct against an anticathode in an X-ray tube, the radiation obtained has a continuous spectrum with a wavelength minimum,

${\lambda }_{min} =\frac{ (1.24 x {10}^{-6})}{V}$) m, where V is the voltage used for accelerating the electrons.

Calculate $\lambda$_min for V= 5 x 10⁴ volts.

1. 1.25 Å

2. 0.75 Å

3. 0.25 Å

4. 1.00 Å

The wavelengths of two photons are 2000 Å and 4000 Å respectively. What is the ratio of their energies?

1. 1/4

2. 4

3. 1/2

4. 2

The number of electrons in one molecule of CO₂ are - 

1. 22

2. 44

3. 66

4. 88