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.
| 751. |
For the circuit shown in the following figure I0-I3 are inputs to the 4:1 multiplexer R(MSB) and S are control bitsThe output Z can be represented by |
| A. | PQ + PQ S + Q R S |
| B. | P Q + PQ R + P Q S |
| C. | P Q R + P QR + PQRS + Q R S |
| D. | PQ R + PQR S + P Q R S + Q R S |
| Answer» C. P Q R + P QR + PQRS + Q R S | |
| 752. |
Polarization is a measure of |
| A. | dielectric constant per unit volume |
| B. | voltage gradient to produce electrical breakdown |
| C. | product of charge and distance |
| D. | excess charge density |
| Answer» B. voltage gradient to produce electrical breakdown | |
| 753. |
A Hartley oscillator uses FET with gm of 2 ms and rd = 2 KΩ. The total coil inductance is 10 μH with turns ratio of input to output side of 1 : 10. It is tuned with a 50 pf capacitor. Find frequency of oscillations, amplifier gain margin in dB. |
| A. | 7.11 MHz, 13.97 dB |
| B. | 7.3 MHz, 14.1 dB |
| C. | 6.93 MHz, 12.9 dB |
| D. | 7.4 MHz, 13 dB |
| Answer» B. 7.3 MHz, 14.1 dB | |
| 754. |
Which one of the following type of negative feedback increases the input resistance and decreases the output resistance of an amplifier? |
| A. | Current series feedback |
| B. | Voltage series feedback |
| C. | Current shunt feedback |
| D. | Voltage shunt feedback |
| Answer» C. Current shunt feedback | |
| 755. |
At room temperature, a possible value for the mobility of electrons in the inversion layer of a silicon n-channel MOSFET is |
| A. | 450 cm2/V-s |
| B. | 1350 cm2/V-s |
| C. | 1800 cm2/V-s |
| D. | 3600 cm2/V-s |
| Answer» C. 1800 cm2/V-s | |
| 756. |
A discrete time linear shift-invariant system has an impulse response h[n] with h[0] = 1, h[1] = - 1, h[2] - 2, and zero otherwise. The system is given an input sequence x[n] with x[0] - x[2] - 1, and zero otherwise. The number of nonzero samples in the output sequence y[n], and the value of y[2] are, respectively |
| A. | 5, 2 |
| B. | 6, 2 |
| C. | 6, 1 |
| D. | 5, 3 |
| Answer» E. | |
| 757. |
What is an advantage of an electronic voltmeter over a non-electronic voltmeter? |
| A. | Low power consumption |
| B. | Low input impedance |
| C. | The ability to measure wide ranges of voltages and resistance |
| D. | Large portability |
| Answer» B. Low input impedance | |
| 758. |
The Boolean expression B‚äïE is a simplified version of expression ABE + BCDE+ BC D E + A B D E + B C D E + A B D E then which of the following choice is correct? don't care conditions doesn't existdon't care conditions existd( 16, 18, 20, 23, 27, 29) is the set of don't care conditionsd( 16, 20, 22, 27, 29) is the set of don't care conditions |
| A. | 1 only |
| B. | 2 and 3 only |
| C. | 2 and 4 only |
| D. | data insufficient |
| Answer» D. data insufficient | |
| 759. |
For a lossless transmission line, the propagation constant is given as γ = __________ . |
| A. | jω LC |
| B. | |
| C. | jω |
| Answer» B. | |
| 760. |
The gradient of any scalar field always yields __________ . |
| A. | a solenoidal field |
| B. | a conservative field |
| C. | an irrotational field |
| D. | none of these |
| Answer» C. an irrotational field | |
| 761. |
It is very likely in __________ gate family that when one gate is driving number of gates in __________ , a gate having least voltage for saturation may consume large __________ leaving other gates inoperative and this phenomenon is called __________ . |
| A. | DTL, parallel, current, current - sinking |
| B. | DCTL, parallel, current, current-lagging |
| C. | ECL, series, voltage, voltage-deterioration |
| D. | DCTL, series, current, current-lagging |
| Answer» C. ECL, series, voltage, voltage-deterioration | |
| 762. |
In a network with twelve circuit elements and five nodes, what is the minimum number of mesh equations? |
| A. | 24 |
| B. | 12 |
| C. | 10 |
| D. | 8 |
| Answer» E. | |
| 763. |
If a signal f(t/2) has energy is E/n then energy of the signal f(nt) is equal to __________ (n is constant) |
| A. | E/2n2 |
| B. | 2E/n2 |
| C. | E/n2 |
| D. | 2En2 |
| Answer» B. 2E/n2 | |
| 764. |
The time constant of the network shown in figure is |
| A. | 2 RC |
| B. | 5/3 RC |
| C. | RC/2 |
| D. | None of these |
| Answer» C. RC/2 | |
| 765. |
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 resistance seen by the source Vs is |
| A. | 258 Ω |
| B. | 1258 Ω |
| C. | 93 kΩ |
| D. | ‚àû |
| Answer» C. 93 kŒ© | |
| 766. |
An air-filled rectangular waveguide has dimensions 8cm x 10cm . The wavelength of waveguide at frequency 3 GHz |
| A. | 25 cm |
| B. | 100 cm |
| C. | 16.13 cm |
| D. | 23.09 cm |
| Answer» E. | |
| 767. |
What is the propagation constant for air filled wave guide with dimensions a = 1.59" and b = 0.795" at 4.95 GHz. The wave impedance is |
| A. | 400.94 Ω |
| B. | 562.94 Ω |
| C. | 502.80 Ω |
| D. | 492.80 Ω |
| Answer» C. 502.80 Œ© | |
| 768. |
In the following circuit, the switch S is closed at t = 0 The rate of change of current (0 +) is given by |
| A. | 0 |
| B. | |
| Answer» C. | |
| 769. |
A 4 bit shift register is initialized to value 1000 for (Q3, Q2, Q1, Q0). The D input is derived from Q0, Q2 and Q3 through two XOR gates as shown in figure. The pattern 1000 will appear at |
| A. | 3rd pulse |
| B. | 7th pulse |
| C. | 6th pulse |
| D. | 4th pulse |
| Answer» D. 4th pulse | |
| 770. |
A system with transfer function H(z) has impulse response h(.) defined as h(2) = 1, h(3) = -1 and h(k) = 0 otherwise. Consider the following statementsS1: H(z) is a low pass filterS2: H(z) is a FIR filter.Which of the following is correct? |
| A. | Only S2 is true |
| B. | Both S1 and S2 are false |
| C. | Both S1 and S2 are true, and S2 is a reason for S1 |
| D. | Both S1 and S2 are true, but S2 is not a reason for S1 |
| Answer» B. Both S1 and S2 are false | |
| 771. |
Refer to the NAND and NOR latches shown in the figure. The inputs (P1, P2) for both the latches are first made (0, 1) and then, after a few seconds, made (1, 1). The corresponding stable outputs (Q1, Q2) are |
| A. | NAND: first (0, 1) then (0, 1) NOR: first (1, 0) then (0, 0) |
| B. | NAND: first (1, 0) then (1, 0) NOR: first (1, 0) then (1, 0) |
| C. | NAND: first (1, 0) then (1, 0) NOR: first (1, 0) then (0, 0) |
| D. | NAND: first (1, 0) then (1, 1) NOR: first (0, 1) then (0, 1) |
| Answer» D. NAND: first (1, 0) then (1, 1) NOR: first (0, 1) then (0, 1) | |
| 772. |
What is the major cause of creeping in an energy-meter? |
| A. | Over compensation for friction |
| B. | Mechanical vibrations |
| C. | Excessive voltage across the potential coil |
| D. | Stray magnetic fields |
| Answer» B. Mechanical vibrations | |
| 773. |
A short grounded vertical antenna has a length L which is 0.05λ at frequency f. If its radiation resistance at f is R ohms, then its radiation resistance at a frequency 2f will be |
| A. | R/2Ω |
| B. | RΩ |
| C. | 2RΩ |
| D. | 4RΩ |
| Answer» E. | |
| 774. |
Consider a feedback control system with open loop transfer function The type of the closed loop system is __________ . |
| A. | zero |
| B. | one |
| C. | two |
| D. | three |
| Answer» C. two | |
| 775. |
A second order system has the transfer function . With r(t) as the unit step function, the response c(t) of the system is represented by |
| A. | figure (a) |
| B. | figure (b) |
| C. | figure (c) |
| D. | figure (d) |
| Answer» C. figure (c) | |
| 776. |
It is required to match a 200 Ω load to a 450 Ω transmission line. To reduce the SWR along the line to 1, what must be the characteristic impedance of the quarter-wave transformer used for this purpose, if it is connected directly to the load? |
| A. | 90 kΩ |
| B. | 300 kΩ |
| Answer» C. | |
| 777. |
When number of quantization levels are two; then the average transmission power in NRZ polar signaling is __________ that of NRZ unipolar signaling |
| A. | 43497 |
| B. | 43556 |
| C. | 43678 |
| D. | none of these |
| Answer» C. 43678 | |
| 778. |
Following are the properties of impulse function x(t) ∂(t) = x (0)∂(t)∂(- t) = ∂(t) Choose the correct option |
| A. | 1-true, 2-false, 3-true |
| B. | 1-false, 2-true, 3-true |
| C. | 1-true, 2-true, 3-true |
| D. | 1-true, 2-true, 3-false |
| Answer» D. 1-true, 2-true, 3-false | |
| 779. |
In a radar system, the range of R1 is achieved at a frequency f1. Then the range R2 at frequency R2 = 8f1 would be __________ [Neglect effect of 1 on the Beam width.] |
| A. | R2 = R1 |
| B. | R2 = 4R1 |
| C. | R2 = 2R1 |
| D. | R2 = |
| Answer» D. R2 = | |
| 780. |
The Z-inverse of the given Z-transform is __________ |
| A. | unit step |
| B. | unit ramp |
| C. | unit impulse |
| D. | unit parabola |
| Answer» D. unit parabola | |
| 781. |
Consider the differential amplifier shown in figure. (Assume β is very high).IE(approximately) = |
| A. | 2 mA |
| B. | 1 mA |
| C. | 0.5 mA |
| D. | 3 mA |
| Answer» B. 1 mA | |
| 782. |
Figure shows four D type FFs are connected as a shift register using an XOR gate. The initial state and 3 subsequent states for 3 clock pulses are also givenThe state QA QB QC QD after the 4th clock pulse is |
| A. | 0 |
| B. | 1111 |
| C. | 1001 |
| D. | 1000 |
| Answer» E. | |
| 783. |
For the system with given characteristic equation s5 + 4s4 + 8s3 + 8s2 + 7s + 4 = 0 The number of roots on left hand side, right hand side and imaginary axis are respectively. |
| A. | 3, 2, 0 |
| B. | 4, 0, 1 |
| C. | 3, 0, 2 |
| D. | 4, 1, 0 |
| Answer» E. | |
| 784. |
The materials not having negative temperature coefficient of resistivity are |
| A. | metals |
| B. | semiconductors |
| C. | insulators |
| D. | none of the above |
| Answer» B. semiconductors | |
| 785. |
In the following circuit , the comparator output in log: "I" if V1 > V2 and is logic "0" otherwise. The D/A conversion is done as per the relations VDAC = 2n-2 Volts, where b3 (MSB), b2, b1 and b0 (LSB) are the counter outputs. The counter starts from the clear stateThe magnitude of the error between VDAC and Vin at steady state in volts is |
| A. | 0.2 |
| B. | 0.3 |
| C. | 0.5 |
| D. | 1 |
| Answer» D. 1 | |
| 786. |
For the power amplifier circuit shown below, the maximum power dissipated by both output transistor is |
| A. | 9.66 W |
| B. | 30.11 W |
| C. | 31.66 W |
| D. | 33.66 W |
| Answer» D. 33.66 W | |
| 787. |
Which of the following is not an electromagnetic device? |
| A. | Hall transducer |
| B. | Transformer |
| C. | Speedometer |
| D. | Eddy current damping device |
| Answer» B. Transformer | |
| 788. |
Modem warfare has changed from large scale clashes of armies to suppression of civilian populations. Chemical agents that do their work silently appear to be suited to such warfare; and regretfully, there exist, people in military establishments who think that chemical agents are useful tools for their cause, which of the following statements best sums up the meaning of the above passage: |
| A. | Modem warfare has resulted in civil strife. |
| B. | Chemical agents are useful in modem warfare. |
| C. | Use of chemical agents in warfare would be undesirable. |
| D. | People in military establishments like to use chemical agents in war. |
| Answer» D. People in military establishments like to use chemical agents in war. | |
| 789. |
The transfer function of a system is . For a unit-step input to the system the approximate setting time for 2% criterion is : |
| A. | 100 sec |
| B. | 4 sec |
| C. | 1 sec |
| D. | 0.01 sec |
| Answer» C. 1 sec | |
| 790. |
For a message signal m(t) = cos (2pfmt) and the carrier frequency fc, which of the following represents a single side band (SSB) signal? |
| A. | cos (2pfmt) cos (2pfct) |
| B. | cos (2pfct) |
| C. | cos [2p(fc + fm) t] |
| D. | [1 + cos (2pfmt) cos (2pfct)] |
| Answer» D. [1 + cos (2pfmt) cos (2pfct)] | |
| 791. |
The function shown in figure, can represent a probability density function for A __________ . |
| A. | A = 1/4 |
| B. | A = 1/6 |
| C. | A = 1/8 |
| D. | A = 1/2 |
| Answer» D. A = 1/2 | |
| 792. |
For the circuit of the following figure, with an ideal op-amp, the maximum phase shift of the output with reference to the input is : |
| A. | 0° |
| B. | 90° |
| C. | -90° |
| D. | ± 180° |
| Answer» E. | |
| 793. |
In a flash type ADC, employing 15 comparators resolution with 10 volts reference; is expected to be : |
| A. | 0.625 V |
| B. | 0.656 V |
| C. | 0.525 V |
| D. | insufficient data |
| Answer» B. 0.656 V | |
| 794. |
A material has conductivity of 105 mho/m and permeability of 4p x 10-7 H/m. The skin depth at 9 GHz is |
| A. | 1.678 μm |
| B. | 26 μm |
| C. | 17 μm |
| D. | 32.32 μm |
| Answer» D. 32.32 Œºm | |
| 795. |
Find value of i |
| A. | 1A |
| B. | 0A |
| C. | 0.45 A |
| D. | None of these |
| Answer» D. None of these | |
| 796. |
The amplitude of a pair of composite sinusoidal signal y(n) = x1(n) + x2(n) with x1(n) = sin (5pn) x2(n) = 3 sin (5pn) is __________ . |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 1 |
| Answer» B. 3 | |
| 797. |
Consider the Schmitt trigger circuit shown below. A triangular wave which goes from - 12 V to 12 V is applied to the inverting input of the op-amp. Assume that the output of the op-amp moves from +15 V to -15 V. The voltage at the non-inverting switches between |
| A. | -12 V and +12 V |
| B. | -7.5 V and +7.5 V |
| C. | -5 V and +5 V |
| D. | 0 V and 5 V |
| Answer» C. -5 V and +5 V | |
| 798. |
Consider the function where F(s) is the Laplace transform of f(t). What is the steady-state value of f(t)? |
| A. | Zero |
| B. | One |
| C. | Two |
| D. | A value between - 1 and + 1 |
| Answer» E. | |
| 799. |
For pole-zero plot shown, the system is __________ . |
| A. | minimum phase |
| B. | maximum phase |
| C. | mixed phase |
| D. | none of these |
| Answer» B. maximum phase | |
| 800. |
The following circuit represents : |
| A. | A(B + CD) BC |
| B. | |
| C. | AB + BC + ACD |
| Answer» B. | |