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

The most probable radius (in pm) for finding the electron in He⁺ is -

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

Which of the following has the maximum number of  unpaired electons-

1. Mg²⁺

2. Ti³⁺

3. V³⁺

4. Fe²⁺

There are three energy levels in an atom. How many spectral lines are possible in its emission spectra?

1. One

2. Two

3. Three

4. Four

Azimuthal quantum number defines -

1. e/m ratio of electron

2. Spin of electron

3. Angular momentum of electron

4. Magnetic momentum of electron