MCQOPTIONS
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MCQOPTIONS
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 | |