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.
| 601. |
Laplace transform of unit triplet function is __________ . |
| A. | 1 |
| B. | s |
| C. | s2 |
| Answer» D. | |
| 602. |
A uniform plane wave in the free space is normally incident on an infinitely thick dielectric slab (dielectric constant εr = 9). The magnitude of the reflection coefficient is |
| A. | 0 |
| B. | 0.3 |
| C. | 0.5 |
| D. | 0.8 |
| Answer» D. 0.8 | |
| 603. |
Consider a situation where number of minterms with even number of 0's are same as number of minterms with odd number of 1's. Then minterms with even number of 0's and minterms with odd number of 1's are __________ to each other then number of variables is __________ . |
| A. | equivalent, even |
| B. | complement, odd |
| C. | complement, even |
| D. | none of these |
| Answer» D. none of these | |
| 604. |
An AC source or RMS voltage 20V with internal impedance Zs = (1 + 2j) Ω feeds a load of impedance ZL = (7 + 4j) Ω in the figure below. The reactive power consumed by the load is |
| A. | 8 VAR |
| B. | 16 VAR |
| C. | 28 VAR |
| D. | 32 VAR |
| Answer» B. 16 VAR | |
| 605. |
In which direction is the plane wave E = 50 sin (108t + 2z) V/m (where is the unit vector in y-direction), travelling? |
| A. | along y direction |
| B. | along -y direction |
| C. | along z direction |
| D. | along -z direction |
| Answer» E. | |
| 606. |
Complex pole in z-plane is as shown below. This is the pole diagram for __________ . |
| A. | Decaying sinusoidal sequence |
| B. | Growing sinusoidal sequence |
| C. | Decaying non sinusoidal sequence |
| D. | Growing non sinusoidal sequence |
| Answer» B. Growing sinusoidal sequence | |
| 607. |
Consider the common emitter amplifier shown below with the following circuit parameters: β = 100, gm = 0.3861 A/V, r0 = ∞ rp = 259 Ω, Rs = 1 kΩ, RB = 93 kΩ, RC = 250 Ω, RL = 1 kW, C1 = ∞ and C2 = 4.7mF.The lower cut-off frequency due to C2 is |
| A. | 33.9 Hz |
| B. | 27.1 Hz |
| C. | 13.6 Hz |
| D. | 16.9 Hz |
| Answer» B. 27.1 Hz | |
| 608. |
Consider circuit with 4 : 16 Demux below: Now:f1 = (2, 6, 11, 12)f2 = (2, 5, 14)= p(2, 3, 4, 5, 9, 13, 14) |
| A. | only 1 and 3 are correct |
| B. | only 1 is correct |
| C. | only 2 is correct |
| D. | 2 and 3 are correct |
| Answer» E. | |
| 609. |
The amplitude of a random signal uniformly distributed between - 5 V and 5 VIf the signal to quantization noise ratio required in uniformly quantizing the signal is 4.5dB, the step size of the quantization is approximately |
| A. | 0.0333 V |
| B. | 0.05 V |
| C. | 0.0667 V |
| D. | 0.10 V |
| Answer» D. 0.10 V | |
| 610. |
Sampling frequency of sin 100pt + cos 200pt + sin 100pt + cos 200pt is: |
| A. | 100 Hz |
| B. | 200 Hz |
| C. | 400 Hz |
| D. | none of these |
| Answer» E. | |
| 611. |
The reduced form of the functionY(A, B, C, D, E, F) = ‚àëm(0, 1, 2, 3, 4, 6, 7, 8, 9, 12, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 25, 28, 30, 31) is given by: |
| A. | A(C D + E F + D E) + D E |
| B. | (A + C + D + E)(D + E + F) |
| C. | (C + D + E + A)(A + D + E + F) |
| D. | A C D + A E F + A(D ‚äï E) |
| Answer» D. A C D + A E F + A(D ‚äï E) | |
| 612. |
Which of the following antenna is obtained by modifying a waveguide? |
| A. | Microstrip Antenna |
| B. | Helical Antenna |
| C. | Horn Antenna |
| D. | Dipole Antenna |
| Answer» D. Dipole Antenna | |
| 613. |
Consider the network: Impedance of this network as a function of the complex frequency is consists of a certain number of zeros and poles. What is the location of poles? |
| A. | -2 |
| B. | -2, ‚àû |
| C. | 2 |
| D. | 2, ‚àû |
| Answer» C. 2 | |
| 614. |
The impulse response h(t) of a linear time-invariant continuous time system is described by h(t) = exp (at) u(t) + exp (βt) u (- t), where u(t) denotes the unit step function, and a and β are constants. This system is stable if |
| A. | a is positive and β is positive |
| B. | a is negative and β is negative |
| C. | a is positive and β is negative |
| D. | a is negative and β is positive |
| Answer» E. | |
| 615. |
The multiplication of two n bit numbers gives a product of length less than or equal to |
| A. | n bits |
| B. | 2n bits |
| C. | 2n bits |
| D. | 2n - 1 bits |
| Answer» C. 2n bits | |
| 616. |
In a material, the Fermi level is located between the centre of the forbidden band and the conduction band. Then what is that material? |
| A. | A p-type semiconductor |
| B. | An n-type semiconductor |
| C. | An intrinsic semiconductor |
| D. | An insulator |
| Answer» C. An intrinsic semiconductor | |
| 617. |
Which one of the following is a transferred electron device? |
| A. | BARITT diode |
| B. | IMPATT diode |
| C. | TRAPATT diode |
| D. | Gunn diode |
| Answer» E. | |
| 618. |
An audio signal of FM radio station is sampled at a rate of 15% above the Nyquist rate. Signal is sampled in 512 levels and bandwidth of the signal is 4 KHz. The minimum bandwidth required to transmit this signal will be |
| A. | 77 K bits/sec |
| B. | 92 K bits/sec |
| C. | 84.8 K bits/sec |
| D. | 82.8 K bits/sec |
| Answer» E. | |
| 619. |
A fully charged mobile phone with a 12 V battery is good for a 20 minute talktime. Assume that, during the talk time, the battery delivers a constant current of 2 A and its voltage drops linearly from 12 V to 10 V as shown in the figure. How much energy does the battery deliver during this talk time? |
| A. | 220 J |
| B. | 12 kJ |
| C. | 13.2 kJ |
| D. | 14.4 kJ |
| Answer» D. 14.4 kJ | |
| 620. |
A series R-C circuit with R = 3 Ω and XC = 4 Ω at 50 Hz is supplied with a voltage V = 50 + 141.4 sin 314 t. What is the RMS value of the current flowing through the circuit? |
| A. | 0.20833333333333 |
| B. | 0.41666666666667 |
| C. | 20 A |
| D. | 22-36 A |
| Answer» D. 22-36 A | |
| 621. |
A signal x1(t) and x2(t) constitute the real and imaginary parts respectively of a complex valued signal x(t). What form of waveform does x(t) possess? |
| A. | Real symmetric |
| B. | Complex symmetric |
| C. | Asymmetric |
| D. | Conjugate symmetric |
| Answer» E. | |
| 622. |
Which of the following has a major role in implementation of functions calls in C? |
| A. | Processor's registers |
| B. | Data segment |
| C. | The heap |
| D. | System stack |
| Answer» E. | |
| 623. |
A conductor in x-y plane and having length 1 m is moving with a velocity V = (2i + 3j + k) m/sec. A magnetic induction field B = (i + 2j) Wb/m2 is applied to the conductor. The potential difference between the ends of the conductor is |
| A. | 0 |
| B. | 4.88 V |
| C. | 6 V |
| D. | None of these |
| Answer» D. None of these | |
| 624. |
How many number of branches the root loci of the equation s(s + 2)(s + 3) + K(s + 2) = 0 have? |
| A. | Zero |
| B. | One |
| C. | Two |
| D. | Three |
| Answer» E. | |
| 625. |
If the memory chip size is 256 x 1 bits, then the number of chips required to make up 1 kB (1024) bytes of memory is |
| A. | 32 |
| B. | 24 |
| C. | 12 |
| D. | 8 |
| Answer» B. 24 | |
| 626. |
The transfer function of a system is . The characteristic equation of the system is : |
| A. | 2s2 + 6s + 5 = 0 |
| B. | (s + l)2 (s + 2) = 0 |
| C. | 2s2 + 6s + 5 + (s + 1 )2(s + 2) = 0 |
| D. | 2s2 + 6s + 5 - (s + l)2(s + 2) = 0 |
| Answer» D. 2s2 + 6s + 5 - (s + l)2(s + 2) = 0 | |
| 627. |
Consider a unity feedback control system with open-loop transfer function The steady state error of the system due to a unity step input is : |
| A. | zero |
| B. | K |
| C. | 1/K |
| D. | infinite |
| Answer» B. K | |
| 628. |
With respect to the Miller integrator sweep shown below, the sweep rate will be |
| A. | 2 |
| B. | 4 |
| C. | 1.5 |
| D. | 2.5 |
| Answer» B. 4 | |
| 629. |
A heavily doped semiconductor exhibits a __________ such a device is called sensistors. |
| A. | negative temperature coefficient of resistance |
| B. | positive temperature coefficient of resistance till a particular value of temperature and then it shown negative temperature coefficient of resistance |
| C. | positive temperature coefficient of resistance |
| D. | none of the above |
| Answer» D. none of the above | |
| 630. |
The transfer function of a discrete time LTI system is given byConsider the following statements:S1: The system is stable and causal for ROC: |z| > 1/2S2: The system is stable but not causal for ROC: |z| < 1/4S3: The system is neither stable nor causal for ROC: 1/4 < |z| < 1/2Which one of the following statements is valid? |
| A. | Both S1 and S2 are true |
| B. | Both S2 and S3 are true |
| C. | Both S1 and S3 are true |
| D. | S1, S2 and S3 are all true |
| Answer» D. S1, S2 and S3 are all true | |
| 631. |
An antenna array comprises of two dipoles that are separated by wavelength. The dipoles are fed by currents of the same magnitude and 90° in phase. The array factor is: |
| A. | 2 cos - 2 sin |
| B. | 2 cos + 2 sin |
| C. | 2 cos |
| D. | 2 sin |
| Answer» B. 2 cos + 2 sin | |
| 632. |
The equation sin (z) = 10 has |
| A. | no real or complex solution |
| B. | exactly two distinct complex solutions |
| C. | a unique solution |
| D. | an infinite number of complex solutions |
| Answer» B. exactly two distinct complex solutions | |
| 633. |
Given If , then the value of K is |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» E. | |
| 634. |
A message signal x(t) is amplitude modulated with carrier c(t). x(t) = 2 sin 600pt c(t) = 8 cos (2p x 106 t) such that the modulated signal is (8 + 2 sin 600pt) [cos 2p x 106 t] The total side band power is: |
| A. | 2ω |
| B. | 3ω |
| C. | 1ω |
| D. | 0.5ω |
| Answer» D. 0.5œâ | |
| 635. |
The impulse response of an initially relaxed linear system is e-2tu(t) . To produce a response te-2tU(t), the input must be equal to __________ . |
| A. | e-2t U(t) |
| B. | e-lt U(t) |
| C. | e-1u(t) |
| Answer» B. e-lt U(t) | |
| 636. |
The specific gravity of tungsten is 13.8 and its atomic weight is 184.0 Assume that there are two free elements per atom. Then the Fermi level or characteristic energy for the crystal in eV will be |
| A. | 8.95 eV |
| B. | -8.95 eV |
| C. | 7.326 eV |
| D. | -7.326 eV |
| Answer» D. -7.326 eV | |
| 637. |
Suppose that the modulating signal is m(t) = 2cos (2pfmt) and the carrier signal is xC(t) = AC cos(2pfct), which one of the following is a conventional AM signal without over modulation? |
| A. | x(t) = Acm(t)cos(2pfct) |
| B. | x(t) = Ac [1 + m(t)]cos (2pfct) |
| C. | |
| Answer» D. | |
| 638. |
In analog signal given below is sampled at such a rate that the samples of signal can be given to a collection of buffers having capacity of either 24 samples/sec. or 25 samples/sec. The sampling rate is minimum such that it fully utilizes the collection of both types of buffers m(t) = 2 sin 480pt + 3 sin 720 pt The folding (maximum) frequency is |
| A. | 600 Hz |
| B. | 300 Hz |
| C. | 1200 Hz |
| D. | 2400 Hz |
| Answer» C. 1200 Hz | |
| 639. |
A compensated wattmeter has its reading corrected for error due to which one of the following parameters? |
| A. | Frequency |
| B. | Friction |
| C. | Power consumed in current coil |
| D. | Power consumed in pressure coil |
| Answer» E. | |
| 640. |
For a second-order system with the closed-loop transfer function The settling time for 2-percent band, in seconds, is : |
| A. | 1.5 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 641. |
How can the bandwidth of a control system be increased? |
| A. | By the use of phase lead network |
| B. | By the use of phase lag network |
| C. | By the use of both phase-lag and phase-lead network |
| D. | By the use of cascaded amplifiers in the system |
| Answer» B. By the use of phase lag network | |
| 642. |
For the circuit shown in the figure, D has a transition from 0 to 1 after CLK changes from 1 to 0. Assume gate delays to be negligibleWhich of the following statements is true? |
| A. | Q goes to 1 to the CLK transition and stays at 1 |
| B. | Q goes to 0 at the CLK transition and stays at 10 |
| C. | Q goes to 1 at the CLK transition and goes to 0 when D goes to 1 |
| D. | Q goes to 0 at the CLK transition and goes to 1 when D goes to 1 |
| Answer» D. Q goes to 0 at the CLK transition and goes to 1 when D goes to 1 | |
| 643. |
The resonant frequency of the circuit shown in figure is, |
| A. | 1/22p Hz |
| B. | 1/2p Hz |
| C. | 1/4p Hz |
| D. | 1/2p Hz |
| Answer» D. 1/2p Hz | |
| 644. |
The full form of the abbreviations TTL and CMOS in reference to logic families are |
| A. | Triple Transistor Logic and Chip Metal Oxide Semiconductor |
| B. | Tristate Transistor Logic and Chip Metal Oxide Semiconductor |
| C. | Transistor Transistor logic and Complementary Metal Oxide Semiconductor |
| D. | Trisate Transistor Logic and Complementary Metal Oxide Silicon |
| Answer» D. Trisate Transistor Logic and Complementary Metal Oxide Silicon | |
| 645. |
A transmitted using AM has in modulated carrier output power of 10 KW and can be modulated to a maximum depth of 90% by a sinusoidal modulating voltage without causing overloading. Find the value to which an modulated carrier power can be increased without resulting in overloading if the maximum permitted modulating index is 40% |
| A. | 14 KW |
| B. | 12.96 KW |
| C. | 26.96 KW |
| D. | 2.96 KW |
| Answer» C. 26.96 KW | |
| 646. |
Which of the following equations satisfy Maxwell's equations? |
| A. | Ex = Ey = 0, Ez = cos (y - ct)Bx = cos(y - ct), By = Bz = 0 |
| B. | Ex = Ey = 0, Ez = cos (y- ct)By = cos(y - ct), Bx = Bz = 0 |
| C. | Fy = cos (y - ct), Ex = Ez = 0Bx = cos(y - ct), By = Bz = 0 |
| D. | None of these |
| Answer» B. Ex = Ey = 0, Ez = cos (y- ct)By = cos(y - ct), Bx = Bz = 0 | |
| 647. |
Consider the following statementsA 4 : 16 decoder can be constructed (with enable i/p) by Using four 2 : 4 decoders (each with an enable i/p) onlyUsing five 2 : 4 decoders (each with an enable i/p) onlyUsing two 3 : 8 decoders (each with an enable i/p) onlyUsing two 3 : 8 decoders (each with an enable i/p) only Which of the statements given above is/are correct? |
| A. | 2 and 3 |
| B. | 1 only |
| C. | 2 and 4 |
| D. | none |
| Answer» C. 2 and 4 | |
| 648. |
A power of 100 W is radiated from an isotropic radiator. The power radiated peer unit solid angle and the power density at a distance of 10 km from the antenna is respectively |
| A. | 25 W, 10 W |
| B. | |
| C. | 7.96 W, 0.08 μW |
| Answer» D. | |
| 649. |
In a transmission line terminated with a load equal to the characteristic impedance, the reflection coefficient is |
| A. | 0 |
| B. | 1 |
| C. | -1 |
| D. | Infinity |
| Answer» B. 1 | |
| 650. |
Which of the following statements is not correct for thermistors? |
| A. | They have negative temperature coefficient of resistance |
| B. | The sensing element is made of sintered ceramics, which are oxides of metals in the form of beads |
| C. | The variation of resistance with temperature is linear |
| D. | The resistance value at ambient temperature may range from 100 Ω to 100 kΩ |
| Answer» D. The resistance value at ambient temperature may range from 100 Œ© to 100 kŒ© | |