Class 12 Semiconductor Electronics CBSE Questions & Answers

Class 12 · Semiconductor Electronics

This is Physics Class 12 Semiconductor Electronics CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
Depletion region (space charge) is formed because
  • A
    minority carriers while diffusing to the other side leave behind immobile ionized atoms
  • B
    majority carriers while diffusing to the other side leave behind highly mobile ionized atoms
  • C
    majority carriers while diffusing to the other side leave behind immobile ionized atoms
    Correct
  • D
    majority carriers while drifting to the other side leave behind immobile ionized atoms
2
In a p-n junction, as the diffusion process continues the width of the depletion zone
  • A
    decreases
  • B
    oscillates
  • C
    increases
    Correct
  • D
    remains the same
3
Which of the following is not a semiconductor?
  • A
    Silicon
  • B
    All of these
  • C
    Arsenic
    Correct
  • D
    Germanium
4
In a semiconductor, the forbidden energy gap between the valance band and the conduction band is of the order of
  • A
    ev
    Correct
  • B
    MeV
  • C
    5eV
  • D
    1 MeV
5
The main difference between conductors, semiconductors and insulators is because of
  • A
    Mobility of electrons
  • B
    Width of forbidden energy gap
    Correct
  • C
    Work function
  • D
    energy of electrons
6
In an insulator, the forbidden energy gap between the valance band and conduction band is of the order of
  • A
    5 eV
    Correct
  • B
    \({\rm{1}}{0^{ - {\rm{3}}}}\)eV
  • C
    1 eV
  • D
    2 MeV
7
When the conductivity of a semiconductor is only due to breaking of the covalent bonds, the semiconductor is called
  • A
    donor
  • B
    extrinsic
  • C
    acceptor
  • D
    intrinsic
    Correct
8
A small impurity is added to germanium to get p-type semiconductor. This impurity is a
  • A
    Monovalent substance
  • B
    Pentavalent substance
  • C
    Trivalent substance
    Correct
  • D
    Bivalent substance
9
To obtain a p-type germanium semiconductor, it must be doped with
  • A
    Phosphorus
  • B
    Arsenic
  • C
    Antimony
  • D
    Indium
    Correct
10
The impurity atoms with which pure silicon should be doped to make a p-type semiconductor are those of
  • A
    Antimony
  • B
    Phosphorus
  • C
    Boron
    Correct
  • D
    Bismuth
11
When arsenic is added as an impurity to silicon, the resulting material is
  • A
    none of these
  • B
    n-type semiconductor
    Correct
  • C
    n-type conductor
  • D
    p-type semiconductor
12
When Ge crystal is doped with phosphorus atoms, it becomes
  • A
    p-type
  • B
    n-type
    Correct
  • C
    Insulator
  • D
    superconductor
13
The depletion layer in the p-n junction region is caused by
  • A
    Drift of electrons
  • B
    Diffusion of carriers
    Correct
  • C
    Migration of impurity ions
  • D
    Drift of holes
14
The potential barrier in the depletion layer is due to
  • A
    Holes
  • B
    Electrons
  • C
    Forbidden gap
  • D
    Ions
    Correct
15
A p-n junction has a thickness of the order of
  • A
    \({\rm{1}}{0^{ - {\rm{12}}}}\)cm
  • B
    1 cm
  • C
    1 mm
  • D
    \({\rm{1}}{0^{ - {\rm{6}}}}\)cm
    Correct