Explore topic-wise MCQs in Electrical Engineering.

This section includes 113 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.

51.

The early voltage of a BJT is VA = 75V. The minimum required collector current, such that the output resistance is at least r0 = 200kΩ, is

A. 1.67mA
B. 5mA
C. 0.375mA
D. 0.75mA
Answer» D. 0.75mA
52.

In schotty barrier diode current flows because of?

A. Majority carriers
B. Minority carriers
C. Majority and minority carriers
D. None
Answer» C. Majority and minority carriers
53.

In a JFET gates are always?

A. forward biased
B. reverse biased
C. unbiased
D. none
Answer» D. none
54.

In forward mode npn BJT, if the voltage Vcc is increased then the collector current will increase

A. Due to ohms law, higher Vcc causes higher current
B. Due to base width decrease less carrier recombine in the base region
C. As the gradient of the minority carriers in the base region becomes steeper
D. Due to both the B and C
Answer» E.
55.

In a multi-stage RC coupled amplifier the coupling capacitor______________

A. Limits the low frequency response
B. Limits the high frequency response
C. Does not affect the frequency response
D. Block the DC component without affecting the frequency response
Answer» B. Limits the high frequency response
56.

The primary reason for the widespread use of Silicon in semiconductor device technology is

A. Abundance of silicon on the surface of the earth
B. Larger bandgap of silicon in comparison to germanium
C. Favorable properties of silicon-dioxide (SiO2)
D. Lower melting Point
Answer» D. Lower melting Point
57.

The band gap of silicon at room temperature is________

A. 1.3 eV
B. 0.7 eV
C. 1.1 eV
D. 1.4 eV
Answer» D. 1.4 eV
58.

A PNP transistor can be replaced with an NPN device and the circuit will do the same thing, provided that

A. The power supply or battery polarity is reversed
B. The collector and emitter leads are interchanged
C. The arrow is pointing inward
D. A PNP transistor can never be replaced with NPN transistor
Answer» B. The collector and emitter leads are interchanged
59.

In a PNP circuit, the collector

A. Has a arrow pointing inward
B. Is positive with respect to the emitter
C. Is biased at a small fraction of the base bias
D. Is negative with respect to the emitter
Answer» E.
60.

An emitter follower has high input impedance because

A. Large emitter resistance is used
B. Large biasing resistance is used
C. There is negative feedback in the base emitter circuit
D. The emitter base junction is highly reverse biased
Answer» D. The emitter base junction is highly reverse biased
61.

For the operation of a depletion type N-MOSFET, the gate voltage has to be

A. Low positive
B. High positive
C. High negative
D. Zero
Answer» E.
62.

An intrinsic semiconductor at absolute zero temperature

A. Has a large number of holes
B. Behaves like an insulator
C. Behaves like a metallic conductor
D. Has few holes and same number of electrons
Answer» B. Behaves like an insulator
63.

Compare to BJT the FET has

A. High input impedance
B. High gain bandwidth product
C. Better current controlled behaviour
D. High noise immunity
Answer» B. High gain bandwidth product
64.

The barrier voltage present in a junction diode is the effect of

A. The P side and N side of the junction forming a battery
B. The emf required to move the holes fast enough to have the mobility equal to that of the electrons
C. The recombination of charge carriers across the junction leaving behind the opposite charged ions
D. The voltage needed to make the semiconductor material behave as a conductor
Answer» D. The voltage needed to make the semiconductor material behave as a conductor
65.

Wien bridge oscillator can typically generate frequencies in the range of

A. 1kHz - 1 Mhz
B. 1 Mhz - 10MHz
C. 10MHz - 100MHz
D. 100MHz - 150MHz
Answer» B. 1 Mhz - 10MHz
66.

In a series RLC circuit, which of these quality factors has the steepest curve at resonance?

A. Q = 20
B. Q = 12
C. Q = 8
D. Q = 4
Answer» E.
67.

In an electric circuit, the dual of resistance is

A. conductance
B. capacitance
C. open circuit
D. inductance
Answer» B. capacitance
68.

On the bode phase plot, the slope of [1 + j10ω - ω2/25]2 is

A. 45°/decade
B. 90°/decade
C. 135°/decade
D. 180°/decade
Answer» E.
69.

On the Bode magnitude plot, the slope of the pole 1/(5 + jω)2 is

A. 20 dB/decade
B. 40 dB/decade
C. 40 dB/decade
D. 20 dB/decade
Answer» D. 20 dB/decade
70.

A parallel RLC circuit has C=0.25F & L=2H. The value of R which will create unity damping factor is

A. 1
B. 2
C. 0.5
D. 4
Answer» C. 0.5
71.

The difference between the half power frequencies is called the

A. quality factor
B. resonant frequency
C. bandwidth
D. cutoff frequency
Answer» D. cutoff frequency
72.

How much inductance is needed to resonate at 5 kHz with a capacitance of 12nF?

A. 2652 H
B. 11.844 H
C. 3.333 H
D. 84.33 mH
Answer» E.
73.

Consider the parallel RLC circuit having R= 1, L= 1H, C=1F . What type of response will the circuit produce?

A. Under damped
B. Over damped
C. Critically damped
D. none of these
Answer» B. Over damped
74.

An amplifier without feedback has a voltage gain of a 50,input resistance of 1K & Output resistance of 2.5K. The input resistance of the current-shunt negative feedback amplifier using the above amplifier with a feedback of 0.2 is

A. 1/11K
B. 1/5K
C. 5K
D. 11K
Answer» B. 1/5K
75.

Voltage Series feedback (also called series-shunt feedback) results in

A. Increase in both input & output impedences
B. Decrease in both input & output impedences
C. Increase in input impedence & decrease in output impedence
D. Decrease in input impedence & increase in output impedence
Answer» D. Decrease in input impedence & increase in output impedence
76.

Introducing a resistor in the emitter of a common amplifier stabilizes the dc operating point against variations in

A. Only the temperature
B. Only the β of the transistor
C. Both Temperature & β
D. None of the above
Answer» D. None of the above
77.

The current gain of a BJT is

A. gmr0
B. gm/r0
C. gmrπ
D. gm/r
Answer» D. gm/r
78.

The cascade amplifier is a multistage configuration of

A. CC-CB
B. CE-CB
C. CB-CC
D. CE-CC
Answer» C. CB-CC
79.

Three identical amplifiers with each one having a voltage gain of 50, input resistance of 1K & output resistance of 250,are cascaded. The open circuit voltage gain of combined amplifier is

A. 49dB
B. 51dB
C. 98dB
D. 102dB
Answer» D. 102dB
80.

The most commonly used amplifier in sample & hold circuits is

A. A unity gain non-inverting amplifier
B. A unity gain inverting amplifier
C. An inverting amplifier with a gain of 10
D. An inverting amplifier with a gain of 100
Answer» C. An inverting amplifier with a gain of 10
81.

A voltage source supplied a signal of constant amplitude, from 0 to 40kHz, to an RC lowpass filter. The load resistor experiences the maximum voltage at

A. dc
B. 10 kHz
C. 20 kHz
D. 40 kHz
Answer» B. 10 kHz
82.

What kind of filter can be used to select a signal of one particular radio station?

A. low pass
B. high pass
C. band pass
D. band stop
Answer» D. band stop
83.

When the elements of an RLC circuit are both magnitude scaled and frequency scaled, which quality is unaffected?

A. resistor
B. resonant frequency
C. bandwidth
D. quality factor
Answer» E.
84.

In an amplifier with negative feedback

A. Only the gain of the amplifier is affected
B. Only the gain and bandwidth of the amplifier are affected
C. Only the input and output impedance are affected
D. All of the four parameters mentioned above would be affected
Answer» E.
85.

In class-A amplifier, the output current flows for

A. A part of the cycle or the input signal
B. The full cycle of the input signal
C. Half the cycle of the input signal
D. 3/4th of the cycle of the input signal
Answer» C. Half the cycle of the input signal
86.

The common collector amplifier is also known as

A. Collector follower
B. Base follower
C. Emitter follower
D. Source follower
Answer» D. Source follower
87.

The fan out of a MOS logic gate is higher than that of TTL gates because of its

A. Low input impedance
B. high output impedance
C. Low output impedance
D. High input impedance
Answer» E.
88.

The control terminal (pin 5) of 555 timer IC is normally connected to ground through a capacitor (0.01μF). This is to

A. Protect the IC from inadvertent application of high voltage
B. Prevent false triggering by noise coupled onto the pin
C. Convert the trigger input to sharp pulse by differentiation
D. Suppress any negative triggering pulse
Answer» C. Convert the trigger input to sharp pulse by differentiation
89.

The frequency of oscillation of a tunnel-collector oscillator having L= 30μH and C = 300pf is nearby

A. 267 kHz
B. 1677 kHz
C. 1.68 kHz
D. 2.67 kHz
Answer» E.
90.

When an amplifier is provided with current series feedback, its

A. Input impedance increases and output impedance decreases
B. Input and output impedance both decrease
C. Input impedance decreases and output impedance increases
D. Input and output impedance both increase
Answer» E.
91.

The important characteristic of emitter-follower is

A. High input impedance and high output impedance
B. High input impedance and low output impedance
C. Low input impedance and low output impedance
D. Low input impedance and high output impedance
Answer» C. Low input impedance and low output impedance
92.

The minimum number of flip-flops required to construct a mod-75 counter is

A. 5
B. 6
C. 7
D. 8
Answer» D. 8
93.

Removing bypass capacitor across the emitter leg resistor in a CE amplifier causes

A. increase in current gain
B. decrease in current gain
C. increase in voltage gain
D. decrease in voltage gain
Answer» E.
94.

Removing bypass capacitor across the emitter-leg resistor in a CE amplifier causes

A. increase in current gain.
B. decrease in current gain.
C. increase in voltage gain
D. decrease in voltage gain
Answer» E.
95.

In a bistable multivibrator circuit, commutating capacitor is used

A. to increase the base storage charge
B. to provide ac coupling
C. to increase the speed of response
D. to provide the speed of oscillations
Answer» D. to provide the speed of oscillations
96.

The function of bleeder resistor in a power supply is

A. the same as that of load resistor
B. to ensure a minimum current drain in the circuit
C. to increase the output dc voltage
D. to increase the output current
Answer» C. to increase the output dc voltage
97.

An oscillator of the LC type that has a split capacitor in the circuit is

A. Hartly oscillator
B. Colpitts oscillator
C. Weinbridge oscillator
D. R-C phase shift oscillator
Answer» C. Weinbridge oscillator
98.

Just as a voltage amplifier amplifies signal voltage, a power amplifier

A. amplifies power
B. amplifies signal current
C. merely converts the signal ac power into the dc power
D. merely converts the dc power into useful ac power
Answer» E.
99.

The upper cutoff frequency of an RC coupled amplifier mainly depends upon

A. Coupling Capacitor
B. Emitter bypass capacitor
C. Output capacitance of signal source
D. Inter-electrode capacitance and stray shunt capacitance
Answer» E.
100.

The lowest output impedance is obtained in case of BJT amplifiers for

A. CB configuration
B. CE configuration
C. CC configuration
D. CE with RE configuration
Answer» D. CE with RE configuration