Calculate the wavenumber of lines having the frequency of 5 x 10¹⁶ cycles per sec. 

1. 1.666 x 10⁸m^-1 

2. 0.666 x 10⁸m^-1

3. 4.126 x 10⁶m^-1

4. 3.133 x 10⁴m^-1

Which set of quantum numbers among the following is invalid?

For particles with equal kinetic energy, how is the de Broglie wavelength related to:

1. Directly proportional to its velocity

2. Inversely proportional to its velocity

3. Independent of velocity and mass

4. Unpredictable

Photochemical dissociation of oxygen results in the production of two oxygen atoms, one in the ground state and one in the excited state.

O₂ $\stackrel{\mathrm{hv}}{\to }$ O→O*

The maximum wavelength () needed for this is 174 nm. If the excitation energy O→O* is 3.15 x 10^-19 J. How much energy in kJ mole^-1 is needed for the dissociation of one mole of oxygen into normal atoms in ground state?

1. 498.3 kJ mol^-1

2. 418.3 kJ mol^-1

3. 524.1 kJ mol^-1

4. 612.8 kJ mol^-1

Rutherford's scattering experiment is related to the size of the-

1. Nucleus

2. Atom

3. Electron

4. Neutron

The  energy needed to convert helium atom  to He ⁺² is -79eV. The first ionization energy of this atom is about 

1. 65.4eV

2. 51.8eV

3. 24.6eV

4. 27.2eV

Elements upto atomic number 103 have been synthesized and studied. If a newly discovered element is found to have an atomic number 106, its electronic configuration will be:

1. [Rn] 5f¹⁴, 6d⁴, 7s²

2. [Rn] 5f¹⁴, 6d¹, 7s² 7p³

3. [Rn] 5f¹⁴, 6d, 7s⁰

4. [Rn] 5f¹⁴, 6d⁵, 7s¹

What is the most probable radius (in pm) for finding the electron in He⁺ ?

1. 0

2. 52.9

3. 26.5

4. 105.8

The mass ratio of photons corresponding to the first lines of the Lymann and the Balmer series of the atomic spectrum of hydrogen is :

An electron, practically at rest, is initially accelerated through a potential difference of 100 volts. It then has a de Broglie wavelength=$\lambda$₁Å. It then get retarded through 19 volts and then it has wavelength $\lambda$₂ Å. A further retardation through 32 volts changes the wavelength to $\lambda$₃.

What is ($\lambda$₃-$\lambda$₂)/$\lambda$₁?

1. 20/41

2. 10/63

3. 20/63

4. 10/41