MCQOPTIONS
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MCQOPTIONS
This section includes 905 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.
| 101. |
For the network shown, determine z1 , z0 and Av |
| A. | zi = 1.067 Ω; z0 = 3 kΩ; Av = 280 |
| B. | zi = 1.067 Ω; z0 = 3 kΩ; Av = - 280.37 |
| C. | zi = 937 Ω; z0 = 3 Ω; Av = 281 |
| D. | zi = 937 Ω; z0 = 33 kΩ; Av = - 280.37 |
| Answer» C. zi = 937 Œ©; z0 = 3 Œ©; Av = 281 | |
| 102. |
The op-amp used in nonlinear mode is |
| A. | integrators |
| B. | active filters |
| C. | Schmitt triggers |
| D. | instrumentation amplifiers |
| Answer» C. Schmitt triggers | |
| 103. |
Consider the signal x(n) = 1 + sinn + 3 cosn + cos . Then Fourier series coefficients are __________ . |
| A. | 1, - j, + j, j, - j |
| B. | 1, + j, - j, - j , + j |
| C. | 1, 3 - j, 3 + j, j, - j |
| D. | 1, 3 + j, 3 - j, - j, + j |
| Answer» B. 1, + j, - j, - j , + j | |
| 104. |
A memoryless source emits n symbols each with a probability p. The entropy of the source as a function of n |
| A. | increases as log n |
| B. | decreases as log (1/n) |
| C. | increases as n |
| D. | increases as n log n |
| Answer» D. increases as n log n | |
| 105. |
What does a link budget for satellite communication include? |
| A. | Total cost of satellite |
| B. | Cost of satellite plus launch vehicle |
| C. | Signal and noise levels is dB |
| D. | Margins of error permitted |
| Answer» D. Margins of error permitted | |
| 106. |
Two infinitely long wires carrying current are as shown in the figure below. One wire is in the y-z plane and parallel to the y-axis. The other wise is in the x-y plane and parallel to the x-axis. Which components of the resulting magnetic field are non-zero at the origin? |
| A. | x, y, z components |
| B. | x, y components |
| C. | y, z components |
| D. | x, z components |
| Answer» E. | |
| 107. |
Six sets of electromagnetic waves are given below :30 - 300 KHz10 - 30 KHz3 - 30 MHz300 - 3000 KHz30 - 300 MHz> 300 MHzThere are designated in the following order |
| A. | VLF, LF, MF, HF, VHF, UHF |
| B. | LF, VLF, MF, HF, VHF, VHF |
| C. | LF, VLF, HF, MF, VHF, UHF |
| D. | VHF, VLF, HF, MF, LF, UHF |
| Answer» D. VHF, VLF, HF, MF, LF, UHF | |
| 108. |
The silicon sample with unit cross-sectional area shown below is in thermal equilibrium. The following information is given: T = 300 K, electronic charge = 1.6 x 10-19C, thermal voltage = 26mV and electron mobility = 1350 cm2/V-sThe magnitude of the electron drift current density at x = 0.5 μm is |
| A. | 2.16 x 104 A/cm2 |
| B. | 1.08 x 104 A/cm2 |
| C. | 4.32 x 103 A/cm2 |
| D. | 6.48 x 102 A/cm2 |
| Answer» B. 1.08 x 104 A/cm2 | |
| 109. |
If then for this to be true x(t) is __________ . |
| A. | exp (j2pf/t) |
| B. | exp (-j2pf/t) |
| C. | exp (j2pft) |
| D. | exp (-j2pft) |
| Answer» D. exp (-j2pft) | |
| 110. |
The characteristic equation of a feedback control system is given by s3 + 5s2 + (K + 6)s + K = 0where K > 0 is a scalar variable parameter. In the root-loci diagram of the system the asymptotes of the root-locus for large values of K meet at a point in the s-plane, whose coordinates are : |
| A. | (- 3, 0) |
| B. | (- 2, 0) |
| C. | (- 1, 0) |
| D. | (2, 0) |
| Answer» D. (2, 0) | |
| 111. |
Consider the following: DistortionGainBias stabilizationSensitivityFrequency response Which of these properties of the power amplifier one should concentrate upon while designing a good power amplifier circuit? |
| A. | 1, 2 and 3 |
| B. | 1, 3 and 5 |
| C. | 2, 3 and 4 |
| D. | 4 and 5 |
| Answer» B. 1, 3 and 5 | |
| 112. |
Consider the circuit The line 1 is at stuck at '0' then output Z is equal to: |
| A. | 0 |
| B. | (C + D) |
| C. | 1 |
| D. | (A + B) + (C + D) |
| Answer» C. 1 | |
| 113. |
One of a loss-less transmission line having the characteristic impedance of 75 Ω and length of 1cm is short-circuit. At 3 GHz, the input impedance at the other end of the transmission line is |
| A. | 0 |
| B. | resistive |
| C. | capacitance |
| D. | inductive |
| Answer» E. | |
| 114. |
A lossless transmission line with air dielectric is 6 m long. what is the phase constant? |
| A. | 1p rad/m |
| B. | 2p rad/m |
| C. | 0.2p rad/m |
| D. | 0.1p rad/m |
| Answer» D. 0.1p rad/m | |
| 115. |
The PCM signal shown below uses amplitude level of +1 volt and -1 volt to represent binary symbol 0 and 1 respectively. Each code word consists of 4 bits. The sampled version of analog signal from which this PCM signal is derived is |
| A. | EB596 |
| B. | CD231 |
| C. | DA495 |
| D. | 25B6A |
| Answer» E. | |
| 116. |
For what positive value of K does the polynomial s4 + 8s3 + 24s2 + 32s + K have roots with zero real parts? |
| A. | 10 |
| B. | 20 |
| C. | 40 |
| D. | 80 |
| Answer» E. | |
| 117. |
For parallel RLC circuit, which one of the following statements is NOT correct? |
| A. | The bandwidth of the circuit deceases if R is increased |
| B. | The bandwidth of the circuit remains same if L is increased |
| C. | At resonance, input impedance is a real quantity |
| D. | At resonance, the magnitude of input impedance attains its minimum value |
| Answer» E. | |
| 118. |
Consider the following: OscillatorEmitter followerCascaded amplifierPower amplifier Where of these use feedback amplifiers? |
| A. | 1 and 2 |
| B. | 1 and 3 |
| C. | 2 and 4 |
| D. | 3 and 4 |
| Answer» B. 1 and 3 | |
| 119. |
For an N-point FFT algorithm with N = 2m which one of the following statements is TRUE? |
| A. | It is not possible to construct a signal flow graph with both input and output in normal order |
| B. | The number of butterflies in the mth stage is N/m |
| C. | In-place computation requires storage of only 2N node data |
| D. | Computation of a butterfly requires only one complex multiplication |
| Answer» E. | |
| 120. |
Consider the following assertionsSI: For Zener effect at occur, a very abrupt junction is requiredS2: For quantum tunnelling to occur, a very narrow energy barrier is requiredWhich of the following is correct? |
| A. | Only S2 is true |
| B. | SI and S2 are both true but S2 is not a reason for SI |
| C. | SI and S2 are both true and S2 is a reason for SI |
| D. | Both SI and S2 are false |
| Answer» B. SI and S2 are both true but S2 is not a reason for SI | |
| 121. |
Which of the following quantities cannot be measured/determined using Hall effect? |
| A. | Type of semiconductor (p or n) |
| B. | Mobility of charge carriers |
| C. | Diffusion constant |
| D. | Carrier concentration |
| Answer» D. Carrier concentration | |
| 122. |
The Z transform of a particular signal is given as The practical implementation of the system will be |
| A. | non causal and stable |
| B. | causal and stable |
| C. | unstable and noncausal |
| D. | can't say |
| Answer» C. unstable and noncausal | |
| 123. |
(1 2 1)x = (1 0 0)4 Then x is equal to |
| A. | 2 |
| B. | 3 |
| C. | 5 |
| D. | does not exist |
| Answer» C. 5 | |
| 124. |
The circuit given below: If R1 = R2 = 20 kΩ and C1 = 0.2 μF and C2 = 0.005 μF. Then which of the given statements given below is true? |
| A. | Circuit is band stop with two edge frequency of 39.7875 Hz to 1592 Hz |
| B. | Circuit is band pass with two edge frequency of 39.7875 Hz to 1592 Hz |
| C. | Circuit is oscillator, oscillation at two frequencies 39.7875 Hz to 1592 Hz depending on R3, R4, R5 and R6 |
| D. | None of these |
| Answer» C. Circuit is oscillator, oscillation at two frequencies 39.7875 Hz to 1592 Hz depending on R3, R4, R5 and R6 | |
| 125. |
Find RTH across the terminals A and B |
| A. | 52.28 Ω |
| B. | 58.28 Ω |
| C. | 52.82 Ω |
| D. | 58.82 Ω |
| Answer» E. | |
| 126. |
Consider the following statements: A flip-flop is used to store 1-bit of information. Race-around condition occurs in a J-K flip-flop when both the inputs are 1. Master-slave configuration is used in flip-flops to store 2-bits of information A transparent latch consists of a D-type flip-flop. Which of the above statements is/are correct? |
| A. | 1 only |
| B. | 1, 3 and 4 |
| C. | 1, 2 and 4 |
| D. | 2 and 3 only |
| Answer» D. 2 and 3 only | |
| 127. |
The maximum power dissipation capacity of a transistor is 50 mW. If the collector emitter voltage is 10 V, what is the safe collector current that can be allowed through the transistor? |
| A. | 5 mA |
| B. | 2.5 mA |
| C. | 10 mA |
| D. | 25 mA |
| Answer» C. 10 mA | |
| 128. |
Fourier transform of signal obtained after taking difference between step function and its reverse version is given as __________ . |
| A. | 2jω |
| B. | 2/jω |
| C. | 4/jω |
| D. | 4jω |
| Answer» C. 4/jœâ | |
| 129. |
The transfer function of an RLC circuit is given by quality factor (Q-factor) of this circuit is : |
| A. | 25 |
| B. | 50 |
| C. | 100 |
| D. | 5000 |
| Answer» C. 100 | |
| 130. |
The feedback control system shown in figure is stable for what values of K and T? |
| A. | K < 0, T > - 1 |
| B. | K > 0, T > 0 |
| C. | K > 0, T > - 1 |
| D. | K < 0, T > 0 |
| Answer» D. K < 0, T > 0 | |
| 131. |
The input and output of a continuous time system are respectively denoted by x(t) and y(t) Which of the following descriptions corresponds to a causal system? |
| A. | y(t) = x(t - 2) + x(t + 4) |
| B. | y(t) = x(t - 4) + x(t + 1) |
| C. | y(t) = x(t + 4) + x(t - 1) |
| D. | y(t) = x(t + 5) + x(t + 5) |
| Answer» D. y(t) = x(t + 5) + x(t + 5) | |
| 132. |
Which of the following circuits come under the class of combinational logic circuits? Full adderFull subtractorHalf adderJ-K flip-flopCounter Select the correct answer from the codes given below: |
| A. | 1 only |
| B. | 3 and 4 |
| C. | 4 and 5 |
| D. | 1, 2 and 3 |
| Answer» E. | |
| 133. |
An FM transmitter delivers 80W to a load of 30 W when no modulation is present. The carrier is now frequency modulated by a single sinusoidal signal and the peak frequency deviation is so adjusted to make the amplitude of the second sideband is zero in the given output.J0(0, 0) = 1, J0(2, 4) = 0, J0(3.8) = - 0.4, J0(5.1)= - 0.1J1(2, 4) = 0.52, J1((3.8) = 0, J1(5.1) = - 0.33, J2(2.4) = 0.1J2(3.8)= 0.41, J2(5.1) = 0 The power in all the remaining sidebands is : |
| A. | 84 W |
| B. | 97.44 W |
| C. | 100 W |
| D. | 77.44 W |
| Answer» E. | |
| 134. |
Which one of the following statements is correct for MOSFETS? |
| A. | p channel MOS is easier to produce than n channel MOS |
| B. | n channel MOS must have twice the area of p channel MOS for the same ON resistance |
| C. | p channel MOS has faster switching action than n channel MOS |
| D. | p channel MOS has higher packing density than n channel MOS |
| Answer» B. n channel MOS must have twice the area of p channel MOS for the same ON resistance | |
| 135. |
Consider Continuous time system y(t) = x(t) - . For the system to be linear response ax1(t) + bx2(t) should be ay1(t) + by2(t) with relation between constant 'a' and 'b' as __________ . |
| A. | a + b = 2 |
| B. | a x b = 1 |
| C. | a = b |
| D. | a + b = 1 |
| Answer» E. | |
| 136. |
Which are of the following oscillators is well suited for the generation of wide range audio-frequency sine waves? |
| A. | RC phase-shift oscillator |
| B. | Wien-bridge oscillator |
| C. | Colpitts oscillator |
| D. | Hartley oscillator |
| Answer» C. Colpitts oscillator | |
| 137. |
Which factor determines whether the medium is free space, lossless dielectric, lossy dielectric or good conductor? |
| A. | Attenuation constant |
| B. | Constitutive parameters (σ, μ, ε) |
| C. | Loss tangent |
| D. | Reflection coefficient |
| Answer» D. Reflection coefficient | |
| 138. |
A 3 stage Johnson counter shown in figure is clocked at a constant frequency of fc from the starting state of Q0 Q1 Q2 = 101. The frequency of output Q0 Q1 Q2 will be |
| A. | fc/2 |
| B. | fc/3 |
| C. | fc/6 |
| D. | fc/8 |
| Answer» D. fc/8 | |
| 139. |
Which of the following options is the closest in meaning to the world below:Circuitous |
| A. | cyclic |
| B. | indirect |
| C. | confusing |
| D. | crooked |
| Answer» C. confusing | |
| 140. |
The following graph, the number of trees (P) and the number of cut-sets (Q) are |
| A. | P = 2, Q = 2 |
| B. | P = 2, Q = 6 |
| C. | P = 4, Q = 6 |
| D. | P = 4, Q = 10 |
| Answer» B. P = 2, Q = 6 | |
| 141. |
Consider the differential amplifier shown in figure. (Assume β is very high).Zin (base) = |
| A. | 1 MΩ |
| B. | 100 kΩ |
| C. | 15 kΩ |
| D. | ≈ 0 |
| Answer» D. ‚âà 0 | |
| 142. |
Calculate the stability factor and change in Ic from 25°C to 100°C for, β = 50, RB/RE = 250, ΔICO = 19.9 nA for emitter bias configuration |
| A. | 42.553, 0.85 μF |
| B. | 40.91, 0.58 μF |
| C. | 38.53, 0.85 μF |
| D. | 41.10, 0.39 μF |
| Answer» B. 40.91, 0.58 ŒºF | |
| 143. |
The property not valid for basic singularity function is |
| A. | it is even signal |
| B. | convolution of any arbitrary function x{t) and an impulse is the original function itself. |
| C. | the sum of two impulses at same location is the impulse with the strength equal to the summation of individual strengths. |
| D. | none of these. |
| Answer» E. | |
| 144. |
Consider the following circuits. Assume all gates to have finite propagation delayWhich of these circuits generate a periodic square wave at the output Vo? |
| A. | (1) only |
| B. | (1) and (2) only |
| C. | (2) (3) and (4) only |
| D. | All (1) (2) (3) and (4) |
| Answer» D. All (1) (2) (3) and (4) | |
| 145. |
In the derivation of expression for peak percent overshoot, , Which one the following conditions is NOT required? |
| A. | System is linear and time invariant |
| B. | The system transfer function has a pair of complex conjugate poles and no zeros. |
| C. | There is no transportation delay in the system. |
| D. | The system has zero initial conditions. |
| Answer» D. The system has zero initial conditions. | |
| 146. |
In the circuit shown, what value of RL maximizes the power delivered to RL? |
| A. | 2.4 Ω |
| B. | |
| C. | 4 Ω |
| Answer» D. | |
| 147. |
A periodic rectangular signal, x(t) has the waveform shown in the given figure. Frequency of the fifth harmonic of its spectrum is __________ |
| A. | 200 Hz |
| B. | 250 Hz |
| C. | 400 Hz |
| D. | 1250 Hz |
| Answer» E. | |
| 148. |
The ratio of condition current density to displacement current density for a good conductor and a good dielectric is respectively __________ . |
| A. | greater than 1, greater than 1 |
| B. | greater than 1, less than 1 |
| C. | less than 1, less than 1 |
| D. | 2n |
| Answer» C. less than 1, less than 1 | |
| 149. |
The following k-map implements |
| A. | BCD to Decimal Decoder |
| B. | Decimal to BCD Encoder |
| C. | 1 of 10 Decoder |
| D. | (a) and (c) |
| Answer» E. | |
| 150. |
Two linearly polarized plane waves A and B travelling in free space in the positive x direction meet at a point. Wave A is polarized in the y direction and the wave B is polarized in the z direction. If the two waves are of equal amplitude and are in phase quadrature, the resultant wave will be |
| A. | circularly polarized |
| B. | elliptically polarized |
| C. | linearly polarized |
| D. | vertically polarized |
| Answer» B. elliptically polarized | |