Electrical engineering/Microwave Engineering MCQs Set-7 Sample Test,Sample questions

Question: ```A class B amplifier consists of _______ transistors in order to conduct the input signal over the entire cycle. ```

1.1

2.2

3.4

4.6

Posted Date:-2022-05-31 17:23:33

Question: ```A dielectric resonator can be incorporated into a circuit to provide _________ using either parallel or series arrangement. ```

1.frequency stability

2.oscillations

3.high gain

4.optimized reflection coefficient

Posted Date:-2022-05-31 10:07:35

Question: ```A dielectric resonator is modeled as __________ when it is used as a tuning circuit with a oscillator. ```

1.series RLC circuit

2.parallel RLC circuit

3.LC circuit

4.tank circuit

Posted Date:-2022-05-31 10:04:55

Question: ```A GSM cellular telephone standard requires a minimum of 9 dB rejection of interfering signal levels of -23 dBm at 3 MHz from the carrier, -33 dBm at 1.6 MHz from the carrier, and -43 dBm at 0.6 MHz from the carrier, for a carrier level of -99 dBm. Determine the required local oscillator phase noise at 3 MHz carrier frequency offset. ```

1.-138 dBc/Hz

2.-128 dBc/Hz

3.-118 dBc/Hz

4.None of the mentioned

Posted Date:-2022-05-31 10:13:18

Question: ```A major advantage of differential amplifiers is: ```

1.high gain

2.low input impedance

3. higher output voltage swing

4.none of the mentioned

Posted Date:-2022-05-31 17:19:33

Question: ```A major disadvantage of frequency multipliers is that they multiply the noise factor along with frequency. ```

1.true

2.false

Posted Date:-2022-05-31 16:25:54

Question: ```A network is said to be conditionally stable if: ```

1.Ð“inâ”‚<1, â”‚Ð“outâ”‚<1.

2.Ð“inâ”‚>1, â”‚Ð“outâ”‚>1

3.Ð“inâ”‚>1, â”‚Ð“outâ”‚<1

4.Ð“inâ”‚<1, â”‚Ð“outâ”‚>1

Posted Date:-2022-05-31 17:05:14

Question: ```A practical oscillator has a frequency spectrum consisting of a single delta function at its operating frequency. ```

1.True

2. False

Posted Date:-2022-05-31 10:10:14

Question: ```A quartz crystals equivalent circuit is a series LCR circuit and has a series resonant frequency. ```

1.true

2.false

Posted Date:-2022-05-31 09:35:44

Question: ```A reactive diode multiplier uses _______ as the key electronic component for frequency multiplication. ```

1.zener diode

2.light emitting diode

3.varactor diode

4.Gunn diode

Posted Date:-2022-05-31 16:25:19

Question: ```A rectangular horn antenna has an aperture area of 3Î» Ã— 2Î». If the aperture efficiency of an antenna is 90%, then the directivity of the antenna is: ```

1.19 dB

2.17.1 dB

3.13 dB

4.21.1 dB

Posted Date:-2022-05-31 17:30:29

Question: ```A rectangular horn antenna has an aperture area of 3Î» Ã— 2Î». Then the maximum directivity that can be achieved by this rectangular horn antenna is: ```

1.24 dB

2.4 dB

3.19 dB

4.Insufficient data

Posted Date:-2022-05-31 17:29:55

Question: ```Advantage of using GaAs in MESFET as compared to use of silicon is: ```

1.GaAs are cost effective

2.they have higher mobility

3.they have high resistance for flow of current in the reverse direction

4.none of the mentioned

Posted Date:-2022-05-31 09:25:54

Question: ```Amplifier efficiency is the ratio of RF output power to DC input power. This parameter determines the performance of an amplifier. ```

1.True

2.False

Posted Date:-2022-05-31 17:21:29

Question: ```An essential requirement for the BARITT diode is that the intermediate drift region be completely filled to cause the punch through to occur. ```

1.true

2.false

Posted Date:-2022-05-31 16:31:53

Question: ```An idealized power spectral density of amplifier has a straight line parallel to X axis and the noise is constant at all frequencies. ```

1.True

2.False

Posted Date:-2022-05-31 10:11:40

Question: ```An inductor is operating at frequency of 50 MHz. Its inductance is 0.1 ÂµH, and then the series resistance associated with the inductor is: (Qo=100) ```

Posted Date:-2022-05-31 09:31:00

Question: ```Any device with negative impedance as its characteristic property can be called: ```

1.Energy source

2.Energy sink

3.Oscillator

4.None of the mentioned

Posted Date:-2022-05-31 09:57:06

Question: ```At frequencies above 10GHz, MESFET are not suitable for microwave applications due to parasitic effects. ```

1.true

2.false

Posted Date:-2022-05-31 09:25:16

Question: ```At higher frequencies of operation of an oscillator, induced noise is mostly: ```

1.Thermal noise

2.White noise

3.Shot noise

4.Flicker noise

Posted Date:-2022-05-31 10:12:17

Question: ```Bandwidth of balanced amplifier can be an octave or more, but is limited by the bandwidth of the coupler. ```

1.true

2.false

Posted Date:-2022-05-31 17:15:47

Question: ```Behavior of a transistor in power amplifiers is unpredictable at all input signal levels. ```

1.True

2.False

Posted Date:-2022-05-31 17:24:32

Question: ```By performing the K-âˆ† test for a given transistor the values of K and âˆ† were found to be equal to 0.383 and 0.334 respectively. The transistor with these parameters has unconditional stability. ```

1.True

2.False

Posted Date:-2022-05-31 17:08:57

Question: ```Colpitts oscillator in the feedback section has an inductance of 4 mH and capacitors of 12 nH and 4 nH. Then the resonant frequency of Colpitts oscillator is: ```

1.50.4 kHz

2.35.1 kHz

3.45.9 kHz

4.None of the mentioned

Posted Date:-2022-05-31 09:32:04

Question: ```Colpitts oscillator operating at 50 MHz has an inductor in the feedback section of value 0.10ÂµH. then the values of the capacitors in the feedback section is: ```

1.100 pF, 100 pF

2.100 pF, 50 pF

3.70 pF, 130 pF

4.80 pF, 60 pF

Posted Date:-2022-05-31 09:30:21

Question: ```Coupler that is mostly used in balanced amplifiers to achieve the required performance is: ```

1.branch line coupler

2.wilkinson coupler

3.lange coupler

4.waveguide coupler

Posted Date:-2022-05-31 17:16:31

Question: ```Distributed amplifiers offer very high _________ ```

1.gain

2.bandwidth

3.attenuation

4.none of the mentioned

Posted Date:-2022-05-31 17:17:06

Question: ```Field effect transistors are different from BJTs in that they are _________ ```

1.monopolar devices

2.bipolar devices

3.bidirectional device

4.none of the mentioned

Posted Date:-2022-05-31 09:24:31

Question: ```For a resistive frequency multiplier of multiplication factor 2, the maximum theoretical conversion efficiency is: ```

1.50 %

2.25 %

3.75 %

4.12.5 %

Posted Date:-2022-05-31 16:28:22

Question: ```For a transistor amplifier to be stable, either the input or the output impedance must have a real negative part. ```

1.True

2.False

Posted Date:-2022-05-31 17:03:40

Question: ```For any passive source termination Ð“S, Unconditional stability implies that: ```

1.â”‚Ð“outâ”‚<1

2.â”‚Ð“outâ”‚>1

3.â”‚Ð“inâ”‚<1

4.â”‚Ð“inâ”‚>1

Posted Date:-2022-05-31 17:06:35

Question: ```GaAs MESFET â€“metal semiconductor field effect transistor are one of the widely used categories of FETs. ```

1.true

2.false

Posted Date:-2022-05-31 09:24:49

Question: ```Gain of an amplifier is independent of the operating frequency. ```

1.True

2.False

Posted Date:-2022-05-31 17:01:26

Question: ```Gain of an antenna is always greater than the directivity of the antenna. ```

1.True

2.False

Posted Date:-2022-05-31 17:29:10

Question: ```Gain of power amplifiers __________ with increase in operating frequency. ```

1.Increases

2.Decreases

3.Increases exponentially

4.Decreases exponentially

Posted Date:-2022-05-31 17:22:09

Question: ```Hartley oscillator has inductance values of 12 mH and 4 mH in the feedback section and a capacitor of 4 nF. Then the resonant frequency of the circuit is: ```

1.19.89 kHz

2.25 kHz

3.45 kHz

4.12 kHz

Posted Date:-2022-05-31 09:31:28

Question: ```High gain is not achievable at microwave frequencies using BJT amplifiers because: ```

1.device construction

2.complex architecture

3.ports are not matched at high frequencies

4.none of the mentioned

Posted Date:-2022-05-31 17:12:51

Question: ```If a frequency multiplier has a multiplication factor of 10, then the increase in noise level due to frequency multiplication is: ```

1.10 dB

2.20 dB

3.25 db

4.15 dB

Posted Date:-2022-05-31 16:26:37

Question: ```If a power amplifier has an output power of 10 W, and an amplifier gain of 16.4 dB, then the input drive power is: ```

1.400 mW

2.225 mW

3.229 mW

4.240 mW

Posted Date:-2022-05-31 17:25:43

Question: ```If an antenna has a directivity of 16 and radiation efficiency of 0.9, then the gain of the antenna is: ```

1.16.2

2.14.8

3.12.5

4.19.3

Posted Date:-2022-05-31 17:28:09

Question: ```If the equivalent impedance of the resonator at resonance is 12.5 Î© and the characteristic impedance of the feed line is 50 Î©, then the coupling coefficient is: ```

1.0.25

2.0.5

3.0.75

4.1

Posted Date:-2022-05-31 10:09:41

Question: ```If the input impedance of a diode used in the microwave oscillator is 45-j23 Î©, then the load impedance is to achieve stable oscillation is: ```

Posted Date:-2022-05-31 09:58:16

Question: ```If the load impedance of a two port network is 40 Î© and the characteristic impedance is 50 Î©, then the reflection coefficient of the two port network at the load end is: ```

1.-0.111

2.-0.333

3.-0.987

4.None of the mentioned

Posted Date:-2022-05-31 17:02:11

Question: ```If the output power of an amplifier is 10 V, and the input power supplied to the amplifier is 0.229 V given that the DC voltage used is 38.5 V, efficiency of the power amplifier is: ```

1.25%

2.50%

3.75%

4.35%

Posted Date:-2022-05-31 17:25:08

Question: ```If the reflection coefficient between the feed line and the resonator is -0.6, then the equivalent impedance of the resonator at resonance given that the characteristic impedance of the microstrip line is: ```

4.none of the mentioned

Posted Date:-2022-05-31 10:09:09

Question: ```If the reflection coefficient seen on the terminated microstrip line looking towards the resonator is 0.5, then the coupling coefficient is: ```

1.0.5

2.0.25

3.0.234

4.1

Posted Date:-2022-05-31 10:05:48

Question: ```IMPATT diodes employ impact ionization technique which is a noisy mechanism of generating charge carriers. ```

1.true

2.false

Posted Date:-2022-05-31 16:31:29

Question: ```Important factors to be considered for power amplifier design are: ```

1.Efficiency

2.Gain

3.Thermal effect

4.All of the mentioned

Posted Date:-2022-05-31 17:21:04

Question: ```In a microwave oscillator, a load of 50+50j is connected across a negative resistance device of impedance -50-50j. Steady state oscillation is not achieved in the oscillator. ```

1.True

2.False

Posted Date:-2022-05-31 09:57:31

Question: ```In a transistor amplifier, if the input impedance is -84-j1.9 Î©, then the terminating impedance required to create enough instability is: ```

4.None of the mentioned

Posted Date:-2022-05-31 10:00:02

Question: ```In a two port network, the source impedance was measured to be 25 Î© and the characteristic impedance of the transmission line was measured to be 50 Î©. Then the reflection coefficient at the source end is: ```

1.-0.33333

2.-0.1111

3.0.678

4.0.2345

Posted Date:-2022-05-31 16:42:13

Question: ```In an oscillator, the resonant feedback circuit must have must have a low Q in order to achieve stable oscillation. ```

1.true

2.false

Posted Date:-2022-05-31 09:34:11

Question: ```In conventional amplifiers, a flat gain response is achieved at the cost of reduced gain. But this drawback can be overcome by using: ```

1.balanced amplifiers

2.distributed amplifiers

3.differential amplifiers

4. none of the mentioned

Posted Date:-2022-05-31 17:14:26

Question: ```In distributed amplifiers, all the FET stages in the amplifier are connected in series to one another. ```

1.true

2.false

Posted Date:-2022-05-31 17:17:31

Question: ```In MESFET, an applied signal at the gate modulates the electron carriers; this produces _______ in the FET. ```

1.voltage amplification

2.voltage attenuation

3.electron multiplication

4.electron recombination

Posted Date:-2022-05-31 09:26:29

Question: ```In oscillator tuning circuits, dielectric resonators are preferred over waveguide resonators because: ```

1.they have high Q factor

2.compact size

3.they are easily integrated with microwave integrated circuits

4.all of the mentioned

Posted Date:-2022-05-31 10:01:53

Question: ```In the equivalent circuit of a quartz crystal, LCR arm has an inductance of 4 mH and capacitor has a value of 4nF, then the series resonant frequency of the oscillator is: ```

1.0.25 MHz

2.2.5 MHz

3.25 MHz

4.5 MHz

Posted Date:-2022-05-31 09:53:02

Question: ```In the plot of reactance v/s frequency of a crystal oscillator, the reactance between series resonant frequency and parallel resonant frequency is: ```

1.capacitive

2.inductive

3.both capacitive and inductive

4.none of the mentioned

Posted Date:-2022-05-31 09:52:09

Question: ```In transistor oscillators, FET and BJT are used. Instability is achieved by: ```

1.Giving a negative feedback

2.Giving a positive feedback

3.Using a tank circuit

4.None of the mentioned

Posted Date:-2022-05-31 09:59:24

Question: ```In transistor oscillators, the requirement of a negative resistance device is satisfied using a varactor diode. ```

1.True

2.False

Posted Date:-2022-05-31 09:58:44

Question: ```It is desired to design a frequency oscillator at 2.4 GHz and the reflection coefficient desired is 0.6, then the coupling coefficient between the feed line and the dielectric resonator is: ```

1.1.5

2.1

3.0.5

4.none of the mentioned

Posted Date:-2022-05-31 10:08:13

Question: ```Maximum transducer gain for an amplifier is the same as the maximum gain for an amplifier. ```

1.True

2.False

Posted Date:-2022-05-31 17:12:00

Question: ```Noise power versus frequency for an amplifier has spikes at the operating frequency without the application of an input voltage. ```

1.True

2.False

Posted Date:-2022-05-31 10:11:18

Question: ```One condition to be satisfied in an oscillator circuit so that stable oscillations are produced is: ```

1.positive feedback is to be achieved

2.negative feedback is to be achieved

3.180degree phase shift is required between the transistor input and output.

4.none of the mentioned

Posted Date:-2022-05-31 09:33:09

Question: ```Oscillators operating at millimeter wavelength are difficult to realize and are also less efficient. ```

1.true

2.false

Posted Date:-2022-05-31 10:14:33

Question: ```Power amplifiers in the increasing order of efficiency is: ```

1.Class A, B, C

2.Class C, A, B

3.Class B, A, C

4. Efficiency of all the 3 amplifiers is the same

Posted Date:-2022-05-31 17:24:11

Question: ```Quartz crystal and tourmaline used in oscillators work on the principle of: ```

1.photo electric effect

2.piezo electric effect

3.Raman effect

Posted Date:-2022-05-31 09:35:19

Question: ```Quartz crystal is used in the _______region, where the operating point of the crystal is fixed. ```

1.resistive

2.inductive reactance

3.capacitive reactance

4.none of the mentioned

Posted Date:-2022-05-31 09:51:07

Question: ```Quartz crystals are more efficient as a feedback network because: ```

1.less circuit complexity

2.cost effective

3.crystals operate at high voltage levels

4.LC circuits have unloaded Q of a few hundreds

Posted Date:-2022-05-31 09:34:44

Question: ```Reactive multipliers have a disadvantage that they cannot be used at very high frequencies and they become less efficient. ```

1.true

2.false

Posted Date:-2022-05-31 16:27:48

Question: ```Resistive multipliers are more efficient as compared to reactive multipliers. ```

1.true

2.false

Posted Date:-2022-05-31 16:27:12

Question: ```Stability condition of an amplifier is frequency independent and hence can be operated at any frequency. ```

1.True

2.False

Posted Date:-2022-05-31 17:05:39

Question: ```The condition for unconditional stability of a transistor as per the K-âˆ† test is â”‚âˆ†â”‚> 1 and K<1. ```

1.True

2. False

Posted Date:-2022-05-31 17:08:08

Question: ```The coupling factor between the resonator and the microstrip line is the ratio of external Q to the unloaded Q. ```

1.true

2.false

Posted Date:-2022-05-31 10:05:14

Question: ```The criterion on which oscillations are produced in the oscillator circuit is called: ```

1.Shannonâ€™s criteria

2.Barkhausen criteria

3.Colpitts criteria

4.None of the mentioned

Posted Date:-2022-05-31 09:29:47

Question: ```The equivalent circuit of a quartz crystal has LCR arm capacitance of 12nF and inductance of 3mH and parallel arm capacitance of 4nF. Parallel resonant frequency for the circuit is: ```

1.3 MHz

2.0.3 MHz

3.6 MHz

4.9 MHz

Posted Date:-2022-05-31 09:55:28

Question: ```The equivalent circuit of a quartz crystal has LCR arm capacitance of 12nF and inductance of 3mH and parallel arm capacitance of 4nF. Parallel resonant frequency for the circuit is: ```

1.3 MHz

2.0.3 MHz

3.6 MHz

4.9 MHz

Posted Date:-2022-05-31 09:56:28

Question: ```The frequency of operation of an FET is limited by: ```

1.drain to source voltage

2.gate to source voltage

3.gate length

4.effective area of an FET

Posted Date:-2022-05-31 09:27:01

Question: ```The frequency response of an amplifier is _______ ```

1.Wide band

2.Narrow band

3.Pass band

4.None of the mentioned

Posted Date:-2022-05-31 17:10:35

Question: ```The major drawback of frequency multipliers is that they have: ```

1.higher attenuation

2.complex construction methods

3.complex design

4. none of the mentioned

Posted Date:-2022-05-31 14:32:32

Question: ```The material used to fabricate IMPATT diodes is GaAs since they have the highest efficiency in all aspects. ```

1.true

2.false

Posted Date:-2022-05-31 16:30:18

Question: ```The maximum transducer gain occurs when the source and the load are matched to the impedance Z of the transistor by lossless method. ```

1.True

2.False

Posted Date:-2022-05-31 17:11:40

Question: ```The most affected parameter of a receiver by the phase noise is signal to noise ratio. ```

1.True

2.False

Posted Date:-2022-05-31 10:13:39

Question: ```The overall gain of a transistor is always a fixed value and cannot be changed as per design requirements. ```

1.True

2.False

Posted Date:-2022-05-31 17:09:57

Question: ```The power gain G of a two port network is independent of the source impedance of the two port network. ```

1.True

2.False

Posted Date:-2022-05-31 16:40:41

Question: ```The stability of an oscillator is enhanced with the use of: ```

1.high Q tuning network

2.passive elements

3.appropriate feedback methods

4.none of the mentioned

Posted Date:-2022-05-31 10:01:09

Question: ```The transfer function of an RF oscillator is given by: ```

1.A/ (1-AH (Ï‰))

2.A/ (1+AH (Ï‰))

3.A/ (-1+AH (Ï‰))

4.1/ (1-AH (Ï‰))

Posted Date:-2022-05-31 09:29:13

Question: ```To flatten the gain response of a transistor: ```

1.biasing current has to be increased

2.input signal level has to increased

3.increase the operational bandwidth

4.give negative feedback to the amplifier

Posted Date:-2022-05-31 17:13:48

Question: ```Unconditionally stable devices can always be ____________ for maximum gain. ```

1.Lossless matched

2.Conjugate matched

3.Forward biased

4.Driven with high current

Posted Date:-2022-05-31 17:11:18

Question: ```With an increase in operating frequency, the background noise temperature: ```

1.Increases

2.Decreases

3.Remains constant

4.Remains unaffected

Posted Date:-2022-05-31 17:31:07

Question: ```with the increase in the operating frequency of a BJT, the S22 parameter of the transistor: ```

1.increases

2.decreases

3.remains constant

4.none of the mentioned

Posted Date:-2022-05-31 16:35:05

Question: ```with the increase in the operating frequency of a BJT, the S22 parameter of the transistor: ```

1.increases

2.decreases

3.remains constant

4.none of the mentioned

Posted Date:-2022-05-31 16:35:51

Question: ```_________ is a non linear circuit that converts DC power to an AC waveform of desired frequency based on the oscillator design. ```

1.Attenuator

2.Amplifier

3.Oscillator

4.None of the mentioned

Posted Date:-2022-05-31 09:28:43

Question: ```__________ amplifiers are linear circuits, where the transistor is biased to conduct over the entire range of the input signal cycle. ```

1.Class A amplifiers

2.Class B amplifiers

3.Class C amplifiers

4.None of the mentioned

Posted Date:-2022-05-31 17:22:57

Question: ```__________ is an example for a frequency multiplier. ```

1.resistor

2. inductor

3.capacitor

4.transistor

Posted Date:-2022-05-31 14:31:39

Question: ```__________ is defined as the ratio of power available from the two port network to the power available from the source. ```

1.Transducer power gain

2.Available power gain

3.Power gain

4.None of the mentioned

Posted Date:-2022-05-31 16:41:28

Question: ```___________ due to random fluctuations caused by thermal and other noise sources appear as broad continuous distribution localized about the output signal. ```

1.Phase noise

2.White noise

3.Thermal noise

4. Shot noise

Posted Date:-2022-05-31 10:10:49

Question: ```____________ condition, if met then the transistor can be impedance matched for any load. ```

1.Conditional stability

2.Unconditional stability

3.Infinite gain

4.Infinite input impedance

Posted Date:-2022-05-31 17:04:29

Question: ```____________ uses balanced input and output, meaning that there are 2 signal lines, with opposite polarity at each port. ```

1.differential amplifier

2.distributed amplifier

3.balanced amplifier

4.none of the mentioned

Posted Date:-2022-05-31 17:18:15

Question: ```_______________ are used in the final stages of radar and radio transmitters to increase the radiated power level. ```

1.Power amplifiers

2.Oscillators

3.Transistors

4.Attenuators

Posted Date:-2022-05-31 17:20:31

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