Solid State Physics II - SS3 Physics Past Questions and Answers - page 1
Which of the following statements is true about energy bands in a solid?
The valence band is completely filled with electrons
The conduction band is completely filled with electrons
The energy gap between valence and conduction bands is fixed and independent of the material
A semiconductor has a larger energy gap than an insulator
Which of the following statements is true about the energy bands in a semiconductor?
The valence band is empty
The conduction band is partially filled
The energy gap between the valence and conduction bands is very small
Semiconductors are metallic in nature
In which of the following materials is the energy gap between the valence and conduction bands the largest?
Metals
Semiconductors
Insulators
Superconductors
Which of the following statements is true about doping in semiconductors?
N-type doping involves adding impurities that create holes in the valence band
P-type doping involves adding impurities that create free electrons in the conduction band
Doping is used to increase the conductivity of semiconductors
Both N-type and P-type doping increase the conductivity of semiconductors
Which of the following statements is true about the Fermi level in a solid?
It represents the energy at which the density of states is highest
It is always located in the conduction band
It determines the maximum energy of an electron in a solid
It is a measure of the average energy of the electrons in a solid
What is band theory?
Band theory describes the behaviour of electrons in solids. According to band theory, the electrons in a solid are restricted to specific energy levels, which are formed into energy bands. These energy bands can be either filled with electrons (called valence bands) or empty (called conduction bands).
What is the significance of band theory?
The band theory helps in understanding the electrical and optical properties of solids, including the behaviour of semiconductors, conductors, and insulators. It also helps in the design and development of electronic devices, such as transistors and microchips.
Which of the following materials is an example of a good conductor?
Silicon
Glass
Copper
Diamond
Which of the following materials is an example of a semiconductor?
Gold
Aluminum
Silicon
Glass
What is the energy gap between the valence and conduction bands in an insulator?
Zero
Small
Intermediate
Large