MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 1362 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics & Communication Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1101. |
The decoder for PAL system is |
| A. | similar to NTSC decoder |
| B. | similar to NTSC decoder supplemented by 64 ms delay line |
| C. | similar to NTSC decoder supplemented by 64 ms delay line and an electronic commutator |
| D. | either (b) or (c) |
| Answer» D. either (b) or (c) | |
| 1102. |
Zero mean Gaussian noise of variance N is applied to a half wave rectifier. The mean squared value of the rectified output will be |
| A. | 0 |
| B. | N/2 |
| C. | N/2 |
| D. | N |
| Answer» C. N/2 | |
| 1103. |
The video heads, in VCR, feed the other circuit |
| A. | directly windings |
| B. | through a transformer having two rotating windings |
| C. | through a transformer having two stationary windings |
| D. | through a transformer having one stationary and one rotatory winding |
| Answer» E. | |
| 1104. |
The number of spectral component when two cosine waves are multiplied of different frequency |
| A. | 1 |
| B. | 2 |
| C. | 8 |
| D. | 4 |
| Answer» E. | |
| 1105. |
One of the advantages of base modulation over collector modulation of a transistor class C amplifier is |
| A. | improved efficiency |
| B. | better linearity |
| C. | high power output per transistor |
| D. | the lower modulating power requirement |
| Answer» E. | |
| 1106. |
The HV and other voltage supplies for a TV receiver are obtained from IHVT. The full name for this device is |
| A. | Internal high voltage transformer |
| B. | Integrated high voltage transformer |
| C. | Instant high voltage transformer |
| D. | Interleaved high voltage transformer |
| Answer» C. Instant high voltage transformer | |
| 1107. |
If velocity of sound waves in air at 0°C is 330 m/s, the velocity at 40°C is about |
| A. | 330 m/s |
| B. | 334 m/s |
| C. | 353 m/s |
| D. | 380 m/s |
| Answer» D. 380 m/s | |
| 1108. |
In a TV, studio the function of vision switcher is to |
| A. | edit television programs |
| B. | relay television programs |
| C. | control zoom lens |
| D. | mix audio and video signals |
| Answer» B. relay television programs | |
| 1109. |
Counterpoise is used in coils having |
| A. | high resistivity |
| B. | low resistivity |
| C. | medium resistivity |
| D. | both (b) and (c) |
| Answer» B. low resistivity | |
| 1110. |
A monostable multivibrator is used to generate PWM because it can |
| A. | differentiator |
| B. | integrator |
| C. | voltage-to-frequency converter |
| D. | generate pulses |
| Answer» E. | |
| 1111. |
In a Vidicon camera tube, |
| A. | both sides of the target plate have the coating of tin oxide |
| B. | both sides of the target plate have the coating of antimony tri-sulphide |
| C. | the side of target plate facing the light has a coating of tin oxide and the side facing electron gun has a coating of antimony trisulphide |
| D. | the side of target plate facing the light has a coating of antimony trisulphide while the side facing the electron gun has a coating of tin oxide |
| Answer» D. the side of target plate facing the light has a coating of antimony trisulphide while the side facing the electron gun has a coating of tin oxide | |
| 1112. |
A sinusoidal signal with peak to peak amplitude of 1.536 volt is quantized into 128 levels using a mid-rise uniform quantizer. The quantization noise power is |
| A. | 0.768 V |
| B. | 48 x 10-6 V |
| C. | 12 x 10-6 V |
| D. | 3.072 Volt |
| Answer» D. 3.072 Volt | |
| 1113. |
Ground wave can be used for communication upto |
| A. | 5 kHz |
| B. | 12 kHz |
| C. | 16 kHz |
| D. | 25 kHz |
| Answer» D. 25 kHz | |
| 1114. |
DVD uses |
| A. | Laser beam for both recording and playback |
| B. | Laser beam for recording and video head for playback |
| C. | Video head for recording and laser beam for playback |
| D. | None of the above |
| Answer» B. Laser beam for recording and video head for playback | |
| 1115. |
If the plate supply voltage for a plate modulated class C amplifier is E, the maximum plate cathode voltage could be almost as high as |
| A. | E |
| B. | 2 E |
| C. | 3 E |
| D. | 4 E |
| Answer» D. 4 E | |
| 1116. |
The modulation index of an AM wave is changed from 0 to 1. The transmitted power is |
| A. | unchanged |
| B. | halved |
| C. | increased by 50% |
| D. | quadrupled |
| Answer» D. quadrupled | |
| 1117. |
In radar display system PPI stands for |
| A. | Pulse Position Indicator |
| B. | Plan Position Indicator |
| C. | Phase Position Indicator |
| D. | Point Position Indicator |
| Answer» C. Phase Position Indicator | |
| 1118. |
The antenna diameter of a radar system is doubled. The maximum range will |
| A. | be doubled |
| B. | become four times |
| C. | be halved |
| D. | decrease to one fourth |
| Answer» B. become four times | |
| 1119. |
Among the various modulation systems, the most favoured from the point of linearity of modulation and efficiency is |
| A. | anode or collector modulation |
| B. | central grid modulation |
| C. | screen grid modulation |
| D. | modulated oscillators |
| Answer» B. central grid modulation | |
| 1120. |
Armstrong modulator generates |
| A. | AM signals |
| B. | FM signals |
| C. | PM signals |
| D. | both (b) and (c) |
| Answer» E. | |
| 1121. |
If D is diagonal and F is focal length, lens angle θ is |
| A. | θ = tan-1 (D/F) |
| B. | θ = 2 tan-1 (D/F) |
| C. | θ = tan-1 (D/2F) |
| D. | θ = 2 tan-1 (D/2F) |
| Answer» E. | |
| 1122. |
For demodulating PCM; it is first converted into |
| A. | PDM |
| B. | PPM |
| C. | PWM |
| D. | PAM |
| Answer» E. | |
| 1123. |
The tuned circuit of the oscillator in a simple AM transmitter employs a 50 H coil and a 1 nanofarad capacitor. If the oscillator output is the carrier frequency will be |
| A. | 448 kHz |
| B. | 555 kHz |
| C. | 625 kHz |
| D. | 712 kHz |
| Answer» E. | |
| 1124. |
In sound recording the degree of pre-emphasis is about 6 dB/ octave. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 1125. |
Which of the following is true in a tape recorder? |
| A. | Vow is due to variation in motor speed but flutter is due to some other reason |
| B. | Both vow and flutter are due to variations in motor speed |
| C. | Flutter is due to variation in motor speed but vow is due to some other reason |
| D. | Neither vow nor flutter is due to variation in motor speed |
| Answer» C. Flutter is due to variation in motor speed but vow is due to some other reason | |
| 1126. |
When large amount of power is required, a push pull amplifier is designed for operation as |
| A. | class A |
| B. | class B |
| C. | class C |
| D. | class AB |
| Answer» C. class C | |
| 1127. |
Fourier analysis indicate that a square wave can be represented as |
| A. | a fundamental sine wave and odd harmonics |
| B. | a fundamental sine wave and even harmonics |
| C. | a fundamental sine wave and harmonics |
| D. | fundamental and subharmonic sine waves |
| Answer» B. a fundamental sine wave and even harmonics | |
| 1128. |
In phase shift keying the input signal is |
| A. | st(t) = A cos ω0t and s2(t) = - A cos ω0t |
| B. | s1(t) = s2(t) = A cos ω0t |
| C. | s1(t) = A cos ω0t and s2(t) = A cos (ω0t + p/2) |
| D. | s1(t) = A cos ω0t and s2(t) = - A (cos ω0t + p/2) |
| Answer» B. s1(t) = s2(t) = A cos œâ0t | |
| 1129. |
For a given carrier wave, maximum undistorted power is transmitted when value of modulation is |
| A. | 1 |
| B. | 0.8 |
| C. | 0.5 |
| D. | 0 |
| Answer» B. 0.8 | |
| 1130. |
The total number of pulses in a TV remote control is |
| A. | 14 |
| B. | 12 |
| C. | 10 |
| D. | 8 |
| Answer» B. 12 | |
| 1131. |
The power consumption of a present day colour TV receiver is about |
| A. | 8 W |
| B. | 80 W |
| C. | 200 W |
| D. | 400 W |
| Answer» C. 200 W | |
| 1132. |
In a fascimile reproduction time to scan one line is 2 ms. If it has 4% blanking, the visible trace time is |
| A. | 1.92 ms |
| B. | 2.08 ms |
| C. | 50 ms |
| D. | 0.08 ms |
| Answer» B. 2.08 ms | |
| 1133. |
In filter system of sideband suppression the advantage of using mechanical filter is |
| A. | smaller size |
| B. | good bandpass |
| C. | good attenuation characteristics |
| D. | all of the above |
| Answer» E. | |
| 1134. |
Full duplex operation |
| A. | requires modems at both ends of circuit |
| B. | requires two pairs of cables |
| C. | can transfer data in both directions simultaneously |
| D. | all of the above |
| Answer» E. | |
| 1135. |
If e = 10 sin(108 t + 3 sin 104 t) then the modulation index is |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 1136. |
Thermal noise has a power spectral density which is quite uniform upto frequencies in the order of |
| A. | 100 Hz |
| B. | 106 Hz |
| C. | 109 Hz |
| D. | 1013 Hz |
| Answer» E. | |
| 1137. |
Frequency shifting keying is basically a method involving |
| A. | amplitude modulation |
| B. | frequency modulation |
| C. | phase modulation |
| D. | none of the above |
| Answer» C. phase modulation | |
| 1138. |
MTI stands for |
| A. | Moving Target Indicator |
| B. | Microprocessor Tracking Index |
| C. | Multiplexed Telemetry Index |
| D. | Maximum Transmission Index |
| Answer» B. Microprocessor Tracking Index | |
| 1139. |
In a colour TV receiver, the function of comb filter is |
| A. | to pass only the clusters of monochrome signal energy while blocking chrome signals |
| B. | to pass only chrome signals and block monochrome signals |
| C. | to block both monochrome and chrome signals |
| D. | none of the above |
| Answer» B. to pass only chrome signals and block monochrome signals | |
| 1140. |
In a superheterodyne broadcast receiver, the frequency of local oscillator is __________ the incoming signal frequency. |
| A. | higher than |
| B. | lower than |
| C. | equal to |
| D. | not comparable to |
| Answer» B. lower than | |
| 1141. |
A line has L = 0.8 µH/m and C = 32 pF/m. Z0 = |
| A. | 6000 |
| B. | 600 |
| C. | 158 |
| D. | 15.8 |
| Answer» D. 15.8 | |
| 1142. |
In FSK no synchronous carrier is needed at the receiver |
| A. | 1 |
| B. | |
| C. | depend on distance |
| D. | none |
| Answer» C. depend on distance | |
| 1143. |
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 | |
| 1144. |
A telephone exchange has 9000 subscribers. If the number of calls originating at peak time is 10, 000 in one hour, the calling rate is |
| A. | 0.9 |
| B. | 43718 |
| C. | 0.81 |
| D. | 0.1 |
| Answer» C. 0.81 | |
| 1145. |
Square law modulators utilise |
| A. | linear range of V-I characteristics of a diode |
| B. | linear range of V-I characteristics of a triode |
| C. | non-linear region of V-I dynamic characteristics of a diode |
| D. | non-linear region of V-I dynamic characteristics of a triode |
| Answer» D. non-linear region of V-I dynamic characteristics of a triode | |
| 1146. |
If there are M messages and each message has probability , the entropy is |
| A. | 0 |
| B. | 1 |
| C. | log2 M |
| D. | M log2 M |
| Answer» D. M log2 M | |
| 1147. |
An FM transmitter has maximum frequency deviation of 75 kHz and reproduces audio signals up to 15 kHz. Minimum channel width required is __________ kHz. |
| A. | 180 |
| B. | 120 |
| C. | 90 |
| D. | 60 |
| Answer» C. 90 | |
| 1148. |
Compact discs use |
| A. | magnetic recording and retrieval |
| B. | optical recording and retrieval |
| C. | optical recording but magnetic retrieval |
| D. | magnetic recording but optical retrieval |
| Answer» C. optical recording but magnetic retrieval | |
| 1149. |
As per Shannon-Hartley theorem, a noise less Gaussian channel has |
| A. | zero capacity |
| B. | infinite capacity |
| C. | small capacity |
| D. | none of the above |
| Answer» C. small capacity | |
| 1150. |
Which one of the following is not necessarily an advantage of the phase cancellation method of obtaining SSB over the filter method? |
| A. | It is possible to generate SSB at any frequency |
| B. | SSB with lower audio frequencies present can be generated |
| C. | Switching from one sideband to other is simpler |
| D. | There are more balanced modulators; therefore the carrier is suppressed better |
| Answer» E. | |