HARD
Earn 100

Describe the conduction band and valence band in metals.

Important Questions on Solids

EASY
Consider a situation in which reverse biased current of a particular P-N junction increases when it is exposed to a light of wavelength 621 nm. During this process, enhancement in carrier concentration takes place due to generation of hole-electron pairs. The value of band gap is nearly.
EASY
The band gap in Ge and Si in eV respectively is
EASY
The band gaps of an insulator, conductor and semiconductor are respectively Eg1, Eg2 and Eg3. The relationship between them is given as _____.
EASY
Fermi level in the case of intrinsic semiconductor lies
EASY

State anyone difference between the energy band diagram of conductors and that of insulators.

EASY

The chromium ions doped in the ruby rod:

EASY
Which of the energy band diagrams shown in the figure corresponds to that of a semiconductor?
EASY
The Forbidden gap between conduction band & valance band is maximum for ______
EASY
Draw separate energy band diagrams for conductors, semi-conductors and insulators and label each of them.
EASY

The band gaps of an insulator, semiconductor and conductor are respectively Eg1, Eg2 and Eg3.The relationship between them can be given as:

EASY
If the forbidden energy gap in a substance is 1 eV, substance is a
EASY
Choose  the correct option :
Electrical conductivity of a semiconductor-
 
EASY
The scientific principle involved in 'Laser' is____
EASY
Arrange the following in order of increasing band gap
MEDIUM

Match the List I with List II

  List I   List II
A Intrinsic Semiconductor I Fermi-level near valence band
B n-type semiconductor II Fermi-level at middle of valence and conduction band
C p-type semiconductor III Fermi-level near conduction band
D Metals IV Fermi-level inside conduction band

Choose the correct answer from the options given below:

EASY
The forbidden energy gap for Ge crystal at 0 K is
MEDIUM

On the basis of band theory, distinguish among insulator, semiconductor, and conductor of electricity.

MEDIUM
Consider the statements
In a semi conductor
(A) There are no free electrons at 0 K.
(B) There are no free electrons at any temperature
(C) The number of free electrons increases with temperature,
(D) The number of free electrons is less than that in a conductor.
EASY
The energy gap is much more in silicon than in germanium because