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WorksheetsSOLID AND SEMICONDUCTOR DEVICES
Total questions: 20
Worksheet time: 9mins
Which of the following statements is incorrect for the depletion region of a diode?
There the mobile charges exist.
Equal number of holes and electrons exist, making the region neutral.
Recombination of holes and electrons has taken place.
None of these
Potential barrier developed in a junction diode opposes the flow of
minority carrier in both regions only
majority carriers only
majority carriers only
holes in p region
The breakdown in a reverse biased p-n junction diode is more likely to occur due to
large velocity of the minority charge carriers if the doping concentration is small
large velocity of the minority charge carriers if the doping concentration is large
strong electric field in a depletion region if the doping concentration is small
none of these
In a half wave rectifier circuit operating from 50 Hz mains frequency, the fundamental frequency in the ripple would be
25 Hz
50 Hz
70.7 Hz
100 Hz
If the energy of a photon of sodium light (A = 589 nm) equals the band gap of semiconductor, the minimum energy required to create hole electron pair
1.1 eV
2.1 eV
3.2 eV
1.5 eV
The circuit has two oppositely connected ideal diodes in parallel. What is the current flowing in the circuit?
2.0 A
1.33A
1.73A
2.31A
At absolute zero, Si acts as a
Semiconductor
conductor
Insulator
Non of these
If a small amount of antimony is added to germanium crystal
its resistance is increased
it becomes a p-type semiconductor
there will be more free electrons than holes in the semiconductor,
none of these.
n an unbiased p-n junction, holes diffuse from the p-region to n-region because
free electrons in the n-region attract them
they move across the junction by the potential difference
hole concentration in p-region is more as compared to u-region.
all of these
In reverse biasing:
In reverse biasing:
no current flows
depletion layer resistance increases
potential barrier across junction increases
In intrinsic semiconductor at room temperature, the number of electrons and holes are:
same
different
infinite
zero
(a)
(b)
(c)
(d)
In full wave rectifier, input a.c. current has a frequency v. The output frequency of current is :
V/2
V
2V
NONE
A p-type semiconductor is:
uncharged
positive
negative
Which one of the following statement is false?
A substitution impurity in donor and acceptor atoms does not cause any disturbances in the crystal lattice of semiconducting material.
Mobility of charge carriers equals its average speed v divided by the applied electric field E.
Each donor atom contributes two free electrons to semiconducting crystal lattice.
In an n-type semiconductor, the free electrons concentration approximately equals the density of donor atoms
An electron in conduction band
Is located near the top of the crystal
Is bound to its parent atom
Has no charge
Has a higher energy than an electron in the valence band
A p-type semiconductor has an acceptor density of 1020 atoms/m3 and intrinsic concentration of 2.5×1019 m-1 at 300K. The electron concentration in this p-type semiconductor is
6.25 x 1018
6.25 x 1019
62.5 x 1019
62.5 x 1018
The I-V characteristics of a junction diode is of the form
(a)
(b)
(c)
(d)
In a p-type semiconductor, the acceptor valence band is
close to the valence band of the host crystal
close to conduction band of the host crystal
below the conduction band of the host crystal
above the conduction band of the host crystal
The mobility of free electrons is greater than that of free holes because
they are light
they carry negative charge
they carry negative charge
they require low energy to continue their motion
