FSC and DA- Module 1

The M shell can house ___ electrons

• 2

• 18

• 8

• 32

The maximum number of electrons an orbital can hold

• 2

• 4

• Cannot be determined

• 3

Which among the following statements hold TRUE for solids.

• Electrons cannot freely move through the crystal lattice

• Energy levels (bands) are further divided into subbands

• There exists valid energy levels within the energy band gap of the material

• Electrons can occupy any energy band irrespective of their inherent energy

The lowest energy level, known as the valence band is filled with:

• Bonding electrons

• Anti-bonding electrons

• Holes

• Cannot be determined as it depends on the type of the semiconductor

Which among the following holds TRUE for anti-bonding electrons (Choose ALL that apply)

• They move in higher orbitals

• They are also called the 'free electrons'

• They possess low energy when compared to the bonding electrons

• They exist in the valence band of the semiconductor material

Energy band gap is defined as:

• A physical property of materials that describes the range of energies that electrons are allowed to occupy.

• It is a measure of the energy required for an electron to transition from the conduction band to the valence band

• The energy band gap is the difference between the highest occupied energy level and the lowest unoccupied energy level.

• It is a measure of the energy released by an electron when it makes a transition from the valence band to the conduction band

A conductor has:

• Low conductivity and high resistivity

• High conductivity and high resistivity

• High conductivity and low resistivity

• High to intermediate conductivity depending on the size of the band gap

Electrons in the valence band contribute to electrical conductivity of the semiconductor material

• True

• True, only when these electrons make a successful transition to the conduction band

• False, as electrons in the conduction band participate in conduction

The individual energy levels of silicon atoms interact together to form energy bands of silicon

• True always

• True, only when the distance between the silicon atoms is less than or equal to the lattice constant of the material

• True, only when the distance between the silicon atoms is greater than the lattice constant of the material

• True, only when the distance between the silicon atoms is less than the lattice constant of the material

The graphical representation of energy bands in reciprocal space:

• Energy band diagram

• E-k diagram