• This model suggested that atom is a positively charged sphere in which negatively charged particles are randomly distributed.

• The model tried to explain two properties of atoms then known: that electrons are negatively-charged particles and that atoms have no net electric charge.

• But this model in later times unable to explain the Rutherford experiment.

● Gas Plasma is not a part of Cathode Ray Tube.

● Cathode Ray Tube is made of three parts

1) Electron Gun

2) Shadow Mask

3) Phosphor Screen

● It modulates, accelerates, and deflects electron beams onto the screen to create the images.

On the basis of experiment, Rutherford put forward the nuclear model of an atom, which had the following features:

• There is a positively charged center in an atom called the nucleus. Nearly all the mass of an atom resides in the nucleus.

• The electrons revolve around the nucleus in well-defined orbits.

• The size of the nucleus is very small as compared to the size of the atom.

The stability of the atom could not be explained by this model.

• According to Maxwell’s equation of electromagnetism, an accelerated electron must continuously emit electromagnetic radiation and loses its energy and fall towards the nucleus.

• Thus Rutherford model can’t explain this loss of energy.

Angular momentum (L) = mvr =

(where v is the velocity of electron, n is the orbit in which electron is revolving, m is mass of the electron, and r is the radius of the n^th orbit)

So, option D is correct.

The Heisenberg’s uncertainty principle is,

where  is uncertainty in determining the position and  is the uncertainty in determining the exact momentum of an electron

The rule of maximum multiplicity state that the pairing of electrons in the orbitals belonging to the same subshell (p, d or f) does not take place until each orbital belonging to that subshell has got one electron each i.e., it is singly occupied.

This rule is given by the scientist Friedrich Hund.

Thus, option C is the correct option.