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MCQOPTIONS
This section includes 9294 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 8051. |
Directivity means |
| A. | maximum directive gain |
| B. | zero directive gain |
| C. | minimum directive gain |
| D. | none of the above |
| Answer» B. zero directive gain | |
| 8052. |
In an FM system, when the AF is 500 Hz and the AF voltage is 2.4 V, the deviation is 4.8 kHz. If the AF voltage is now increased to 7.2 V, the new deviation will be |
| A. | 4.8 kHz |
| B. | 9.6 kHz |
| C. | 14.4 kHz |
| D. | 28.8 kHz |
| Answer» D. 28.8 kHz | |
| 8053. |
Modulation is also called detection. |
| A. | True |
| B. | False |
| Answer» C. | |
| 8054. |
The maximum range of a transmitter depends on |
| A. | its frequency |
| B. | its power |
| C. | both its frequency and power |
| D. | none of the above |
| Answer» D. none of the above | |
| 8055. |
Consider the following statements about Yagi Uda antenna It is unidirectionalIts gain is about 7 dBIt is used at VLFThe optimum separation is 0.11 Which of the above are correct? |
| A. | 1 and 2 only |
| B. | 1, 2, 4 only |
| C. | 1, 2, 3, 4 |
| D. | 1 and 4 only |
| Answer» C. 1, 2, 3, 4 | |
| 8056. |
Three analog signals, having bandwidths 1200 Hz, 600 Hz, 600 Hz are sampled at their Nyquist rates, encoded with 12 bit words, and time division multiplexed. The bit rate for the multiplexed signal is |
| A. | 115.2 kbps |
| B. | 28.8 kbps |
| C. | 57.6 kbps |
| D. | 38.4 kbps |
| Answer» D. 38.4 kbps | |
| 8057. |
In a CD player the speed of CD is |
| A. | constant at 500 rpm |
| B. | constant at 200 rpm |
| C. | varies from 200 to 500 rpm |
| D. | none of the above |
| Answer» D. none of the above | |
| 8058. |
In the output of a DM speech encoder, the consecutive pulses are of opposite polarity during time interval t1 < t < t2. This indicates that during this interval |
| A. | the input to the modulator is essentially constant |
| B. | the modulator is going through slope overload |
| C. | the accumulator is in saturation |
| D. | the speech signal is being sampled at the Nyquist rate |
| Answer» B. the modulator is going through slope overload | |
| 8059. |
A fascimile reproduction has a specification of 200 lines per frame, progressive scanning and 5 frames per second. The time to scan one line is |
| A. | 5 ms |
| B. | 2.5 ms |
| C. | 1 ms |
| D. | 0.1 ms |
| Answer» D. 0.1 ms | |
| 8060. |
A carrier is modulated by two modulating waves A and B having modulation indices of 0.6 and 0.8 respectively. The overall modulation index is |
| A. | 1 |
| B. | 0.7 |
| C. | 0.2 |
| D. | 1.4 |
| Answer» B. 0.7 | |
| 8061. |
A communication channel disturbed by additive white, Gaussian noise has a bandwidth of 4 kHz and SNR of 15. The highest transmission rate that this channel can support (in k bits/sec) is |
| A. | 16 |
| B. | 1.6 |
| C. | 3.2 |
| D. | 60 |
| Answer» B. 1.6 | |
| 8062. |
Which of the following microphones is used as a standard for calibration? |
| A. | Moving coil |
| B. | Carbon |
| C. | Condenser |
| D. | Ribbon |
| Answer» D. Ribbon | |
| 8063. |
The reactance of coupling capacitor for AC signals in an amplifier, should be |
| A. | as low as possible |
| B. | as high as possible |
| C. | neither low nor high |
| D. | either low or high |
| Answer» B. as high as possible | |
| 8064. |
Which of the following sampling frequencies is considered adequate in voice telephony? |
| A. | 4 kHz |
| B. | 8 kHz |
| C. | 16 kHz |
| D. | 32 kHz |
| Answer» C. 16 kHz | |
| 8065. |
In a tape recorder the output from RF oscillator is given to |
| A. | only erase head coil |
| B. | only record head coil |
| C. | coils of both erase head and record head |
| D. | none of the above |
| Answer» B. only record head coil | |
| 8066. |
Which of the following microphones works on the principle of Faraday's law? |
| A. | Carbon |
| B. | Condenser |
| C. | Moving coil |
| D. | Electret |
| Answer» D. Electret | |
| 8067. |
In a CE amplifier connection, the emitter is at ground potential for |
| A. | AC quantities |
| B. | DC quantities |
| C. | all quantities |
| D. | none of the quantities |
| Answer» B. DC quantities | |
| 8068. |
In an AM wave with m = 1, the carrier is suppressed. The resulting power saving will be |
| A. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/56-3.94-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/56-3.94-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/128-6.72-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/56-3.94-6.png"> |
| Answer» D. <img src="/_files/images/electronics-and-communication-engineering/communication-systems/56-3.94-6.png"> | |
| 8069. |
Directive gain is |
| A. | a power ratio |
| B. | a voltage ratio |
| C. | a current ratio |
| D. | a distance ratio |
| Answer» B. a voltage ratio | |
| 8070. |
A + 1.9 lens has a focal length of 25 mm. The diameter of lens is about |
| A. | 13 mm |
| B. | 1.3 mm |
| C. | 130 mm |
| D. | none of the above |
| Answer» B. 1.3 mm | |
| 8071. |
Which of the following terms are applicable to troposcatter propagation? |
| A. | Faradays rotation |
| B. | SIOs |
| C. | Fading |
| D. | Atmospheric storms |
| Answer» D. Atmospheric storms | |
| 8072. |
Assertion (A): An electronic tuner uses varactor diodeReason (R): The capacitance of a varactor diode depends on the magnitude of reverse bias. |
| A. | Both A and R are correct and R is correct explanation of A |
| B. | Both A and R are correct but R is not correct explanation of A |
| C. | A is correct but R is wrong |
| D. | A is wrong but R is correct |
| Answer» B. Both A and R are correct but R is not correct explanation of A | |
| 8073. |
If the amplitude of the voltage is kept constant, but its frequency is raised to 6 kHz, the new deviation will be for the modulation index is, if fm = 500 Hz, f = 2.25 |
| A. | 6 kHz |
| B. | 12 kHz |
| C. | 27 kHz |
| D. | 54 kHz |
| Answer» D. 54 kHz | |
| 8074. |
In TV scanning sequence of lines is |
| A. | left to right |
| B. | right to left |
| C. | left to right for odd fields and right to left for even field |
| D. | left to right for even fields and right to left for odd field |
| Answer» B. right to left | |
| 8075. |
A noiseless 3 kHz channel can't transmit binary bit at the rate |
| A. | 12000 bps |
| B. | 1000 bps |
| C. | 6000 bps |
| D. | 3000 bps |
| Answer» B. 1000 bps | |
| 8076. |
In an AM wave the carrier and one of the side bands is suppressed. If m = 1, the percentage saving in power is |
| A. | 25% |
| B. | 50% |
| C. | 66.6% |
| D. | 83.3% |
| Answer» E. | |
| 8077. |
A superheterodyne receiver is to operate in the frequency range 550 kHz - 1650 kHz, with the intermediate frequency of 450 kHz. Let denote the required capacitance ratio of the local oscillator and I denote the image frequency (in kHz) of the incoming signal. If the receiver is tuned to 700 kHz, then |
| A. | R = 4.41 J =1600 |
| B. | R = 2.10 J =1150 |
| C. | R = 3.0 J =1600 |
| D. | R = 9.0 J =1150 |
| Answer» B. R = 2.10 J =1150 | |
| 8078. |
The generally used value of EHV supply in TV receivers is |
| A. | 1 kV per diagonal cm |
| B. | 1 kV per diagonal inch |
| C. | 0.5 kV per diagonal cm |
| D. | 0, 5 kV per diagonal inch |
| Answer» C. 0.5 kV per diagonal cm | |
| 8079. |
Computer communication networks have |
| A. | star configuration |
| B. | tree configuration |
| C. | loop/mesh configuration |
| D. | All of the above |
| Answer» E. | |
| 8080. |
Assertion (A): A balun is an RF impedance matching transformer. Reason (R): Sometimes a booster amplifier is used with a TV set. |
| A. | Both A and R are correct and R is correct explanation of A |
| B. | Both A and R are correct but R is not correct explanation of A |
| C. | A is correct but R is wrong |
| D. | A is wrong but R is correct |
| Answer» C. A is correct but R is wrong | |
| 8081. |
The number of channels available in MF band (300 kHz - 3 MHz) for AM modulating signal of 20 kHz is |
| A. | 70 |
| B. | 67 |
| C. | 100 |
| D. | 150 |
| Answer» C. 100 | |
| 8082. |
The function of blend control in stereo system is |
| A. | to dilute left channel |
| B. | to dilute right channel |
| C. | to dilute any of the channels |
| D. | none of the above |
| Answer» D. none of the above | |
| 8083. |
For an ideal 3000 Hz channel, S/N ratio is |
| A. | 3 |
| B. | 1.5 |
| C. | 4 |
| D. | 2 |
| Answer» B. 1.5 | |
| 8084. |
Which of the following types of noise assumes greater importance at high frequencies? |
| A. | Transit time noise |
| B. | Shot noise |
| C. | Impulse noise |
| D. | Random noise |
| Answer» B. Shot noise | |
| 8085. |
To relay outdoor remotely located live programs, TV transmitter use |
| A. | microwave links |
| B. | coaxial cable link |
| C. | open wire link |
| D. | either (b) or (c) |
| Answer» B. coaxial cable link | |
| 8086. |
In transistor radio receivers the number of IF amplifier stages are |
| A. | 1 |
| B. | 2 |
| C. | 4 |
| D. | 6 |
| Answer» C. 4 | |
| 8087. |
If each short element of signal occupies 20 ms, the speed is |
| A. | 20 bauds |
| B. | 50 bauds |
| C. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/523-627-1.png"> |
| D. | bauds |
| E. | 0.05 bauds |
| Answer» C. <img src="/_files/images/electronics-and-communication-engineering/communication-systems/523-627-1.png"> | |
| 8088. |
A PIN diode can be used |
| A. | as a shunt mounted switch |
| B. | as a series mounted switch |
| C. | both as series or shunt mounted switch |
| D. | non of the above |
| Answer» D. non of the above | |
| 8089. |
The speed at which axial electric field due to signal advances in a TWT is equal to |
| A. | speed of light |
| B. | (speed of light) (helix pitch helix circumference) |
| C. | (speed of light) (helix circumference helix pitch) |
| D. | (speed of light) (helix pitch) (helix circumference) |
| Answer» C. (speed of light) (helix circumference helix pitch) | |
| 8090. |
The resistance values of a PIN diode under positive bias and negative bias respectively are about |
| A. | a few ohms and a kilo ohms |
| B. | about 100 ohms and 1000 ohms |
| C. | about 0.1 ohm and 100 ohms |
| D. | about 1000 ohms and 10000 ohms |
| Answer» B. about 100 ohms and 1000 ohms | |
| 8091. |
A rectangular wave guide has two stubs each of length connected at the source end. The stubs are circuited. Then the stubs present |
| A. | an infinite impedance in shunt with line |
| B. | an infinite impedance in series with line |
| C. | a zero impedance in shunt with line |
| D. | a finite impedance in shunt with line |
| Answer» B. an infinite impedance in series with line | |
| 8092. |
Which of the following is not used as a microwave mixer or detector? |
| A. | PIN diode |
| B. | Crystal diode |
| C. | Schottky barrier diode |
| D. | Backward diode |
| Answer» B. Crystal diode | |
| 8093. |
Integrated fin line can be utilized as a medium for constructing millimeter wave circuits. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 8094. |
In the given figure the equivalent circuit of a T attenuator. If the condition for matched attenuator is |
| A. | <img src="/_files/images/electronics-and-communication-engineering/microwave-communication/19-229-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/microwave-communication/19-229-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/microwave-communication/19-229-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/microwave-communication/19-229-4.png"> |
| Answer» B. <img src="/_files/images/electronics-and-communication-engineering/microwave-communication/19-229-2.png"> | |
| 8095. |
If rv is reflection coefficient and VSWR is voltage standing wave ratio, then |
| A. | <img src="/_files/images/electronics-and-communication-engineering/microwave-communication/09-32-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/microwave-communication/09-32-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/microwave-communication/09-32-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/microwave-communication/09-32-4.png"> |
| Answer» C. <img src="/_files/images/electronics-and-communication-engineering/microwave-communication/09-32-3.png"> | |
| 8096. |
If in line the characteristic impedance becomes real. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 8097. |
Assertion (A): Inter-digitated geometry is widely used for microwave transistors.Reason (R): Tuning at input and output of transistor uses MOS chip capacitors. |
| A. | Both A and R are correct and R is correct explanation of A |
| B. | Both A and R are correct but R is not correct explanation of A |
| C. | A is correct but R is wrong |
| D. | A is wrong but R is correct |
| Answer» C. A is correct but R is wrong | |
| 8098. |
For a 1 cm x 2 cm air filled rectangular waveguide the maximum frequency should be less than about |
| A. | 1000 MHz |
| B. | 5000 MHz |
| C. | 14000 MHz |
| D. | 140000 MHz |
| Answer» D. 140000 MHz | |
| 8099. |
Assertion (A): For a reciprocal microwave junction the S matrix is symmetrical.Reason (R): In a symmetrical matrix Sij = Sji. |
| A. | Both A and R are correct and R is correct explanation of A |
| B. | Both A and R are correct but R is not correct explanation of A |
| C. | A is correct but R is wrong |
| D. | A is wrong but R is correct |
| Answer» C. A is correct but R is wrong | |
| 8100. |
The attenuation characteristics of a loaded line is similar to that of |
| A. | low pass filter |
| B. | high pass filter |
| C. | band pass filter |
| D. | band stop filter |
| Answer» E. | |