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
basic materials used in the present solid state electronic devices like diode, transistor, ICs, etc are
  • A
    conductors
  • B
    metals
  • C
    Semiconductors
    Correct
  • D
    insulators
2
In the case of metals the valence and conduction bands have
  • A
    overlap, energy gap =0
    Correct
  • B
    no overlap, energy gap is small
  • C
    no overlap, energy gap =0
  • D
    no overlap, energy gap is large
3
In the case of semiconductors the valence and conduction bands have
  • A
    no overlap, energy gap is small
    Correct
  • B
    no overlap, energy gap is large
  • C
    overlap, energy gap =0
  • D
    no overlap, energy gap =0
4
Hole is a vacancy or lack of an electron and can travel through the material. It can
  • A
    move only if an electron stops
  • B
    serves as an additional current carrier
    Correct
  • C
    only serves as a vacant spot and cannot conduct current
  • D
    None of these
5
In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always present
  • A
    such that number of electrons is greater than the number of holes
  • B
    None of these
  • C
    in equal numbers
    Correct
  • D
    such that number of holes is greater than the number of electrons
6
doping of semiconductor is the process of
  • A
    removing impurity elements
  • B
    adding of impurity elements
    Correct
  • C
    None of these
  • D
    adding a surface coating
7
Motion of hole is a convenient way of describing
  • A
    the actual motion of energy gap
  • B
    the actual motion of free electrons
  • C
    the actual motion of conduction electrons
  • D
    the actual motion of bound electrons
    Correct
8
The total current in a semiconductor is
  • A
    electron current only
  • B
    hole current only
  • C
    the sum of electron and hole currents
    Correct
  • D
    the difference of electron and hole currents
9
In n-type semiconductor the fifth electron
  • A
    is not capable of moving
  • B
    needs low energy to be set free
    Correct
  • C
    is not present
  • D
    needs high energy to be set free
10
In n-type semiconductor the total number of conduction electrons \({{\rm{n}}_{\rm{e}}}\) is due to the,
  • A
    electrons generated intrinsically only
  • B
    holes contributed by donors and those generated intrinsically
  • C
    electrons contributed by donors and those generated intrinsically
    Correct
  • D
    holes generated intrinsically only
11
in n-type semiconductor majority carriers and minority carriers are respectively
  • A
    holes and electrons
  • B
    germanium and silicon
  • C
    aluminum and boron
  • D
    electrons and holes
    Correct
12
in p-type semiconductor the dopant is
  • A
    always germanium
  • B
    donor
  • C
    always silicon
  • D
    acceptor
    Correct
13
in p-type semiconductor
  • A
    \({{\rm{n}}_{\rm{h}}} > > {\rm{ }}{{\rm{n}}_{\rm{e}}}\)
    Correct
  • B
    \({{\rm{n}}_{\rm{h}}} = {\rm{ }}{{\rm{n}}_{\rm{e}}}\)
  • C
    \({{\rm{n}}_{\rm{h}}} > {\rm{ }}{{\rm{n}}_{\rm{e}}}\)
  • D
    \({{\rm{n}}_{\rm{h}}} < {\rm{ }}{{\rm{n}}_{\rm{e}}}\)
14
The electron and hole concentration in a semiconductor in thermal equilibrium is given by
  • A
    \({n_e}{n_h} = n_i^3\)
  • B
    \({n_e}{n_h} = 2n_i^2\)
  • C
    \({n_e}{n_h} = n_i^2\)
    Correct
  • D
    \(2{n_{e}}{n_h} = n_i^2\)
15
Diffusion in a p-n junction is due to
  • A
    carrier injection
  • B
    minority carriers
  • C
    None of these
  • D
    concentration gradient
    Correct