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Question Bank

SAMEER Project Scientific Assistant Exam (Electronics) - English

Duration: 60 · Questions: 60 · Max Marks: 60 · Language: 1

View SAMEER Project Scientific Assistant 2026 Exam Page

Electronics

1
At temperature of 298 Kelvin, Silicon is not suitable for most-electronic applications, due to small amount of conductivity. This can be altered by
  1. A.Gettering
  2. B.Doping
  3. C.Squeezing
  4. D.Sintering
2
By doping Germanium with Gallium, the types of semi-conductors formed are
1. N type
2. P type
3. Intrinsic
4. Extrinsic
  1. A.1 and 4
  2. B.2 and 4
  3. C.1 and 3
  4. D.2 and 3
3
An n-type of silicon can be formed by adding impurity of:
1. Phosphorous
2. Arsenic
3. Boron
4. Aluminum 
Which of the above are correct ?
  1. A.1 and 2
  2. B.2 and 3
  3. C.3 and 4
  4. D.1 and 4
4
According to Einstein’s relationship for a semiconductor, the ratio of diffusion constant to the mobility of the charge carriers is
  1. A.Variable and is twice the volt equivalent of the temperature
  2. B.Constant and is equal to the volt equivalent of the temperature
  3. C.Equal to two and is twice the volt equivalent of the temperature
  4. D.Equal to one and is equal to the volt equivalent of the temperature
5
Swept-out voltage in PIN diode happens when PIN diode is
  1. A.Forward biased and the thickness of the depletion layer decreases till I-region becomes free of mobile carriers
  2. B.Reverse biased and the thickness of the depletion layer increases till I-region becomes free of mobile carriers
  3. C.Forward biased and the thickness of the depletion layer increases till I-region becomes free of mobile carriers
  4. D.Reverse biased and the thickness of the depletion layer decreases till I-region becomes free of mobile carriers
6
The number of holes in an N-type silicon with intrinsic value 1.5 × 1010/cm3 and doping concentration of 1017/cm3, by using mass-action law is
  1. A.6.67 × 106/cc
  2. B.4.44 × 10-25/cc
  3. C.1.5× 10-24/cc
  4. D.2.25 × 103/cc
7
A tunnel-diode is best suited for
  1. A.Very low frequencies
  2. B.50 Hz
  3. C.100 Hz
  4. D.Microwave frequencies
8
Small recovery time of a diode is most significant for
  1. A.Line-frequency rectification
  2. B.Switching operations
  3. C.High-frequency rectifications and switching operations
  4. D.Low-frequency rectifications and switching operations
9
In JFET, when operated above the pinch-off voltage, the
  1. A.Depletion region becomes smaller
  2. B.Drain current starts decreasing
  3. C.Drain current remains practically constant
  4. D.Drain current increases steeply
10
Thermal runaway is not possible in FET because, as the temperature of FET increases
  1. A.The drain current increases
  2. B.The mobility of charge carriers decreases
  3. C.The mobility of charge carriers increases
  4. D.The transconductance increases
11
Consider the following statements regarding an N-P-N Bipolar Junction Transistor:
1. Emitter diode is forward biased and collector diode is reverse biased
2. Emitter has many free electrons
3. Free electrons are injected into base and pass through collector
4. Depletion layers around junction J1 and J2 of BJT are widened 
    Which of the above statements are correct?
  1. A.1, 2 and 4
  2. B.1, 3 and 4
  3. C.2, 3 and 4
  4. D.1, 2 and 3
12
A freewheeling diode T phase controlled rectifier
  1. A.Improves the line power factor
  2. B.Enables inverse operation
  3. C.Is responsible for additional reactive power
  4. D.Is responsible for additional harmonics
13
The zeners incorporated within the encapsulations of some MOSFETs are meant for
  1. A.Reducing the cost
  2. B.Biasing the gate circuit
  3. C.Self-protecting the device against transients
  4. D.None of the above
14
When UJT is used for triggering an SCR, the wave-shape of the signal obtained from UJT circuit is
  1. A.Sine wave
  2. B.Saw tooth wave
  3. C.Trapezoidal wave
  4. D.Square wave
15
Darlington pairs are frequently used in linear ICs because, they
  1. A.Do not require any capacitors or inductors
  2. B.Have enormous impedance transformation capability
  3. C.Can be readily formed/hooked from two adjacent transistors
  4. D.Resemble emitter follower
16
In a MOS capacitance fabricate on a P-type semiconductor, strong inversion occurs, when potential is
  1. A.Equal to Fermi level
  2. B.Zero
  3. C.Negative and equal to Fermi potential in magnitude
  4. D.Positive and equal to Fermi potential in magnitude
17
A CMOS amplifier when compared to an N channel MOSFET has the advantage of
  1. A.Higher cutoff frequency
  2. B.Higher voltage gain
  3. C.Higher current gain
  4. D.Lower power dissipation
18
Consider the following statements regardingoptocouplers:
1. Optocouplers are LEDs driving photodiodes in a single package to provide electrical isolation between input and output
2. Optocouplers is LED driving a phototransistor in a single package that replaces pulse transformers working at input zero crossing
3. Optocouplers are used as temporary non fixed joints between optical fibre terminations 
  Which of the above statements are correct?
  1. A.1, 2 and 3
  2. B.1 and 2 only
  3. C.1 and 3 only
  4. D.2 and 3 only
19
Which of the following does not cause permanent damage to an SCR ?
  1. A.High current
  2. B.High rate of rise of current
  3. C.High temperature rise
  4. D.High rate of rise of voltage
20
The basic structure of an avalanche photodiode is
  1. A.p+ – i – p – n+
  2. B.p+ – I – n+
  3. C.p+ – p- – n+
  4. D.i – p- – n+
21
A five digits number is formed using the digits 1, 3, 5, 7 and 9 without repeating any of them. What is the sum of all such possible five digit numbers ?
  1. A.6666660
  2. B.6666600
  3. C.6666666
  4. D.6666606
22
Examples of an active display and a passive display respectively are
  1. A.LCD and Gas discharge plasma
  2. B.LED and LCD
  3. C.Gas discharge plasma and LED
  4. D.Electrophoretic Image display and LED
23
The dc resistivity and permeability exhibited by a type 1 superconductor are respectively
  1. A.Zero and zero
  2. B.Zero and unity
  3. C.Unity and zero
  4. D.Unity and unity
24
Statement (I):One of the mechanisms by which a transistor’s usefulness may be terminated, as the collector voltage is increased, is called punch through.
Statement (II): Punch through results from the increased width of the collector-junction transition region with increased collector-junction voltage
  1. A.Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)
  2. B.Both Statement (I) and Statement (II) are individually true and Statement (II) is NOT the correct explanation of Statement (I)
  3. C.Statement (I) is true but Statement (II) is false
  4. D.Statement (I) is false but Statement (II) is true
25
Statement (I): Conduction takes place in an enhancement MOSFET only for gate voltages below the threshold level.
Statement (II):In an enhancement MOSFET, a channel of semiconductor of the same type as the source and drain is induced in the substrate by a positive voltage applied to the gate.
  1. A.Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)
  2. B.Both Statement (I) and Statement (II) are individually true and Statement (II) is NOT the correct explanation of Statement (I)
  3. C.Statement (I) is true but Statement (II) is false
  4. D.Statement (I) is false but Statement (II) is true
26
Statement (I): MOSFET is a field effect transistor whose drain current is controlled by the voltage applied at the gate.
Statement (II): MOSFET is an insulated gate FET
  1. A.Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)
  2. B.
    Both Statement (I) and Statement (II) are individually true and Statement (II) is NOT the correct explanation of Statement (I)
  3. C.
    Statement (I) is true but Statement (II) is false
  4. D.
    Statement (I) is false but Statement (II) is true
27
Statement (I): All passive components can be fabricated in a single chip.
Statement (II): As opposed to discrete circuits where all components are separately inserted and connected, in an integrated circuit, they are simultaneously created on a chip of semiconductor material during manufacturing
  1. A.Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)
  2. B.
    Both Statement (I) and Statement (II) are individually true and Statement (II) is NOT the correct explanation of Statement (I)
  3. C.
    Statement (I) is true but Statement (II) is false
  4. D.Statement (I) is false but Statement (II) is true
28
What is an advantage of MOS transistor structure in integrated circuits?
  1. A.
    Faster switching
  2. B.
    Less capacitance
  3. C.
    Higher component density and lower cost
  4. D.
    Lower resistance
29
An LTI system has a wide-sense stationary (WSS) input signal with zero mean. Its output is
  1. A.
    Non-zero mean and non-WSS signal
  2. B.
    Zero mean and WSS signal
  3. C.
    Non-zero mean and WSS signal
  4. D.
    Zero mean and non-WSS signal
30
In degenerately doped n conduction n-type semiconductor, the Fermi level lies in conduction band when
  1. A.
    Concentration of electrons in the conduction band exceeds the density of states in the valence band
  2. B.
    Concentration of electrons in the valence band exceeds the density of states in the conduction band
  3. C.
    Concentration of electrons in the conduction band exceeds the product of the density of states in the valence band and conduction band
  4. D.
    None of the above
31
In intrinsic semiconductors, the Fermi level lies?
  1. A.At mid-gap
  2. B.Near valence band
  3. C.Near conduction band
  4. D.Outside the band gap
32
Which material is a direct band-gap semiconductor?
  1. A.Gallium Arsenide
  2. B.Germanium
  3. C.Silicon
  4. D.Tin
33
Indirect band-gap semiconductors require phonon interaction because?
  1. A.Charge neutrality
  2. B.Energy conservation
  3. C.Momentum conservation
  4. D.Thermal equilibrium
34
Band gap of silicon at room temperature is approximately?
  1. A.0.66 eV
  2. B.0.72 eV
  3. C.1.43 eV
  4. D.1.12 eV
35
Increase in temperature causes band gap of semiconductor to?
  1. A.Increase
  2. B.Decrease
  3. C.Remain constant
  4. D.Become zero
36
Electrical conductivity of intrinsic semiconductor depends mainly on?
  1. A.Doping
  2. B.Crystal size
  3. C.Mobility only
  4. D.Temperature
37
In n-type semiconductor, majority carriers are?
  1. A.Holes
  2. B.Excitons
  3. C.Ions
  4. D.Electrons
38
Density of states in conduction band increases with?
  1. A.Decrease in energy
  2. B.Cube of energy
  3. C.Square root of energy
  4. D.Linear energy
39
Fermi level shifts towards conduction band in?
  1. A.p-type material
  2. B.Intrinsic material
  3. C.n-type material
  4. D.Insulator
40
Semiconductor becomes degenerate when?
  1. A.Lightly doped
  2. B.Undoped
  3. C.Heavily doped
  4. D.Heated
41
Built-in potential of PN junction depends on?
  1. A.Current
  2. B.Temperature and doping
  3. C.Area
  4. D.Frequency
42
Depletion region width increases with?
  1. A.Reverse bias
  2. B.Forward bias
  3. C.Zero bias
  4. D.Temperature rise
43
Reverse saturation current is mainly due to?
  1. A.Majority carriers
  2. B.Drift only
  3. C.Recombination
  4. D.Minority carriers
44
Zener breakdown occurs due to?
  1. A.Avalanche multiplication
  2. B.Tunneling effect
  3. C.Thermal runaway
  4. D.Punch-through
45
Zener breakdown is dominant in diodes with?
  1. A.Wide depletion region
  2. B.Light doping
  3. C.Heavy doping
  4. D.Large junction area
46
Gradient of a scalar field gives a?
  1. A.Vector
  2. B.Scalar
  3. C.Tensor
  4. D.Constant
47
Divergence of a vector field physically represents?
  1. A.Source or sink strength
  2. B.Flux density
  3. C.Curling tendency
  4. D.Energy density
48
Curl of a vector field indicates?
  1. A.Rotational tendency
  2. B.Rate of change
  3. C.Flux
  4. D.Potential
49
Divergence of curl of any vector field is always?
  1. A.Zero
  2. B.Maximum
  3. C.Unity
  4. D.Infinite
50
Curl of gradient of any scalar field is always?
  1. A.Unity
  2. B.Zero
  3. C.Infinite
  4. D.Maximum
51
Del operator is used to represent?
  1. A.Scalar multiplication
  2. B.Vector differentiation
  3. C.Integration
  4. D.Transformation
52
Line integral of electric field around closed path equals?
  1. A.Zero in electrostatics
  2. B.Magnetic flux
  3. C.Charge density
  4. D.Current
53
Volume integral of divergence of vector equals?
  1. A.Surface integral of normal component
  2. B.Line integral
  3. C.Curl integral
  4. D.Zero
54
Gauss divergence theorem relates?
  1. A.Line and surface integrals
  2. B.Surface and volume integrals
  3. C.Line and volume integrals
  4. D.Curl and gradient
55
Stokes theorem relates?
  1. A.Surface integral of divergence
  2. B.Line integral of curl
  3. C.Volume integral of gradient
  4. D.Surface integral of curl to line integral
56
Gauss’s law for electricity relates electric flux to?
  1. A.Magnetic field
  2. B.Electric current
  3. C.Energy
  4. D.Enclosed charge
57
Gauss’s law for magnetism states magnetic monopoles are?
  1. A.Present
  2. B.Variable
  3. C.Absent
  4. D.Infinite
58
Faraday’s law relates induced EMF to?
  1. A.Magnetic flux change
  2. B.Electric flux
  3. C.Charge
  4. D.Energy
59
Maxwell’s displacement current term accounts for?
  1. A.Conduction current
  2. B.Magnetic monopoles
  3. C.Energy loss
  4. D.Time varying electric field
60
Ampere-Maxwell law includes?
  1. A.Static fields only
  2. B.Displacement current
  3. C.Magnetic flux
  4. D.Charge density