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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.
| 651. |
With which decoder it is possible to obtain many code conversions? |
| A. | 2 line to 4 line |
| B. | 3 line to 8 line |
| C. | not possible with any decoder |
| D. | 4 line to 16 line decoder |
| Answer» E. | |
| 652. |
A function n(x) satisfied the differential equation where L is a constant. The boundaryconditions are: n(0) = K and n(‚àû) = 0. The solution to this equation is |
| A. | n(x) = K exp(x/L) |
| B. | n(x) = K exp (-x/L) |
| C. | n(x) = K2 exp (-x/L) |
| D. | n(x) = K exp (-x/L) |
| Answer» E. | |
| 653. |
Which one of the following circuits is used for converting a sine wave into a square wave? |
| A. | Astable multivibration |
| B. | Monostable multivibration |
| C. | Bistable multivibration |
| D. | Schmitt trigger |
| Answer» E. | |
| 654. |
In the following transistor circuit VBE = 0. 7 V, rc = 25mV/IE, and β and the capacitance are very largeThe value of DC current IE is |
| A. | 1 mA |
| B. | 2 mA |
| C. | 5 mA |
| D. | 10 mA |
| Answer» B. 2 mA | |
| 655. |
The antenna current of an AM transmitter is 8 A, when only the carrier is sent, but it increases to 8.93 A when the carrier is modulated by a single sine wave. Determine the antenna current when the percent of modulation changes to 0.8 |
| A. | 9.19 A |
| B. | 9.91 A |
| C. | 10.56 A |
| D. | 8.61 A |
| Answer» B. 9.91 A | |
| 656. |
In the circuit shown, the device connected to Y5 can have address in the range |
| A. | 2000 - 20FF |
| B. | 2D00 - 2DFF |
| C. | 2E00 - 2EFF |
| D. | FD00 - FDFF |
| Answer» C. 2E00 - 2EFF | |
| 657. |
In the following astable multivibrator circuit, which properties of v0(t) depends on R2? |
| A. | Only the frequency |
| B. | Only the amplitude |
| C. | Both the amplitude |
| D. | Neither the amplitude nor the frequency |
| Answer» B. Only the amplitude | |
| 658. |
The amplitude of a random signal uniformly distributed between - 5 V and 5 V. If the positive values of the signal are uniformly quantized with a step size of 0.05 V, and the negative values are uniformly quantized with a step size of 0.10 V, the resulting signal to quantization noise is approximately |
| A. | 46 dB |
| B. | 43.8 dB |
| C. | 42 dB |
| D. | 40 dB |
| Answer» E. | |
| 659. |
Which of the following counters can be used to divide the clock frequency of a microprocessor by 5? |
| A. | 3 bit counter |
| B. | 5 bit counter |
| C. | mod 3 counter |
| D. | mod 5 counter |
| Answer» E. | |
| 660. |
By what name is the equation Δ . J = 0 frequency known? |
| A. | Poisson's equation |
| B. | Laplace's equation |
| C. | Continuity equation for steady currents |
| D. | Displacement equation |
| Answer» D. Displacement equation | |
| 661. |
Thermal noise is passed through an ideal low-pass filter having cut-off at fc = ωHz. The auto correlation value of the noise at the output of the filter is given as |
| A. | Triangular function over the range |
| B. | Gaussian over the range -∞ ≤ t ≤ ∞ |
| C. | A Delta function at t = 0 |
| D. | Sin c function over the range - ∞ ≤ t ≤ ∞ |
| Answer» E. | |
| 662. |
The logic circuit given below converts a binary code y1 y2, y3 into |
| A. | Excess - 3 code |
| B. | Gray code |
| C. | BCD code |
| D. | Hamming |
| Answer» D. Hamming | |
| 663. |
A unity-feedback control system has the open loop transfer function . If the input system is a unit ramp, the steady state error will be |
| A. | 0 |
| B. | 0.5 |
| C. | 2 |
| D. | infinity |
| Answer» D. infinity | |
| 664. |
Which of the following are universal gates? NANDNORXOR Select the correct answer from the codes given below: |
| A. | 1 and 2 only |
| B. | 1 and 3 only |
| C. | 2 and 3 only |
| D. | 1, 2 and 3 |
| Answer» B. 1 and 3 only | |
| 665. |
The transfer function of a linear-time invariant system is given as What is the steady-state value of the unit-impulse response? |
| A. | Zero |
| B. | One |
| C. | Two |
| D. | Infinite |
| Answer» B. One | |
| 666. |
VL = 100 cos (10t + 30°)R = 10 Ω XL = j10 ΩXC = - j4 ΩFind Vs |
| A. | 116.57 sin (10t - 29°) V |
| B. | 116.57 sin (10t + 29°) V |
| C. | 117.00 sin (10t - 29°) V |
| D. | 117.00 sin (10t + 29°) V |
| Answer» B. 116.57 sin (10t + 29¬∞) V | |
| 667. |
Find E at P(1, 1, 1) caused by four identical 3 nC point charges located at P1(1, 1, 0), P2(- 1, 1, 0), P3(- 1, - 1, 0) P4(1, - 1, 0) |
| A. | 21.58ax + 21.58ay + 12az V/m |
| B. | 6.82ax + 6.82ay + 32.89az V/m |
| C. | -6.82ax - 6.82ay - 32.89az V/m |
| D. | -21.58ax - 21.58ay - 12az V/m |
| Answer» C. -6.82ax - 6.82ay - 32.89az V/m | |
| 668. |
Signal flow graph is used to find : |
| A. | stability of the system |
| B. | controllability of the system |
| C. | transfer function of the system |
| D. | poles of the system |
| Answer» E. | |
| 669. |
For a given voltage, four heating coils will produce maximum heat when connected |
| A. | all in parallel |
| B. | all in series |
| C. | with two parallel pairs in series |
| D. | one pair in parallel with the other two in series |
| Answer» B. all in series | |
| 670. |
If x1[n] x1(z) with ROC = R1 and x2[n] x2(z) with ROC = R2 then ROC for x1[n] + x2[n] will be __________ (where Ri ‚Üí Region of convergence and x1[n] and x2[n] are causal). |
| A. | R1 ‚à© R2 |
| B. | R1 ‚à™ R2 |
| C. | (R1 ‚à™ R2) ‚à© (R1) |
| D. | (R1 ‚à© R2) ‚à™ (R1) |
| Answer» B. R1 ‚à™ R2 | |
| 671. |
His rather casual remarks on politics __________ his lack of seriousness about the subject. |
| A. | masked |
| B. | belied |
| C. | cherish |
| D. | conserve |
| Answer» D. conserve | |
| 672. |
If a signal f(t) has energy E, the energy of the signal f(2t) is equal to __________ . |
| A. | E |
| B. | E/2 |
| C. | E/4 |
| D. | 2E |
| Answer» C. E/4 | |
| 673. |
(2)3 + (3)4 = (?)5 |
| A. | 4 |
| B. | 11 |
| C. | none of these |
| D. | not possible |
| Answer» D. not possible | |
| 674. |
The eigen values of the following matrix are |
| A. | 3, 3 + 5j, 5 -j |
| B. | - 6 + 5j, 3 + j, 3 - j |
| C. | 3 + j, 3 - j, 5 + j |
| D. | 3, - 1 + 3j, - 1 - 3j |
| Answer» E. | |
| 675. |
Consider the amplitude modulated (AM) signal Ac cos ωct + 2 cos ωmt cos ωct For demodulating the signal using envelope detector, the minimum value of Ac should be |
| A. | 2 |
| B. | 1 |
| C. | 0.5 |
| D. | 0 |
| Answer» B. 1 | |
| 676. |
The Nyquist plot of a stable, transfer function G(s) is shown in the figure. We are interested in the stability of the closed loop system in the feedback configuration shown.The gain and phase margins of G(s) for closed loop stability are |
| A. | 6 dB and 180° |
| B. | 3 dB and 180° |
| C. | 6 dB and 90° |
| D. | 3 dB and 90° |
| Answer» D. 3 dB and 90¬∞ | |
| 677. |
Assertion (A): As the length of the resonant antenna is increased, the number of lobes increases and the direction of the major lobes is closer and closer to the direction of the diode.Reason (R): As the length increases, the current distribution along the wire becomes more and more uniform. |
| A. | Both A and R are individually true and R is the correct explanation of A |
| B. | Both A and R are individually true but R is not the correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» D. A is false but R is true | |
| 678. |
The resolution of a 4 bit counting ADC is 0.5 volts. For an analog input of 6.6 volts, the digital output of the ADC will be |
| A. | 1011 |
| B. | 1101 |
| C. | 1100 |
| D. | 1110 |
| Answer» E. | |
| 679. |
Consider a parallel plate capacitor being charged. Identify the incorrect statements |
| A. | Energy stored in the capacitor does not enter it through the connecting wires but through the space around the wires and plates uf capacitor |
| B. | Rate at which energy flows into this volume is equal to the integration of the Poynting vector over the boundary of the volume between the plates. |
| C. | The Poynting vector points everywhere radially outward of the volume between the plates |
| D. | The Poynting vector points everywhere radially into the volume between the plates. |
| Answer» E. | |
| 680. |
If (10)x x (10)x = (100)x; (100)x x (100)x = (10000)x then x can take value : |
| A. | 2 |
| B. | 5 |
| C. | 10 |
| D. | all of these |
| Answer» E. | |
| 681. |
Assuming that flip-flops are in reset condition initially, the count sequence observed at QA in the circuit shown is |
| A. | 0010111... |
| B. | 0001011... |
| C. | 0101111... |
| D. | 0110100... |
| Answer» E. | |
| 682. |
An audio signal is to be transmitted digitally. Which is the system best suited for good fidelity? |
| A. | 8 bit PCM |
| B. | 13 bit PCM |
| C. | 32 bit PCM |
| D. | PCM system with non-uniform quantizer |
| Answer» E. | |
| 683. |
A sphere with charge Q was placed in, but not touching a larger hollow sphere. If there is any charge initially on the outer sphere; to remove it the outer sphere was earthed momentarily, and then the inner sphere was removed. The charge remaining on the outer sphere was then measured. This charge was found to be __________ to the charge on the inner sphere. |
| A. | equal and of same again |
| B. | equal and of opposite sign |
| C. | unequal and of same sign |
| D. | unequal and of opposite sign |
| Answer» C. unequal and of same sign | |
| 684. |
Assertion (A): The small signal analysis of a transistor amplifier is done to obtain the current gain, voltage gain and the conversion efficiency of an amplifier.Reason (R): The small signal analysis of a transistor amplifier uses the small signal parameters of the transistor. |
| A. | Both A and R are individually true and R is the correct explanation of A |
| B. | Both A and R are individually true but R is not the correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» E. | |
| 685. |
The z-transform of a signal is given by . Its final value is : |
| A. | 43556 |
| B. | zero |
| C. | 1 |
| D. | infinity |
| Answer» D. infinity | |
| 686. |
The distance between target and radar is reduced to half. Power received increases by |
| A. | 42370 |
| B. | 43556 |
| C. | 4 times |
| D. | 16 times |
| Answer» E. | |
| 687. |
In a certain network not containing any dependent sources, number of nodes = 4 and number of branches is equal to 6. |
| A. | 4 |
| B. | 2 |
| C. | 3 |
| D. | 5 |
| Answer» D. 5 | |
| 688. |
Method of images is applicable to which fields? |
| A. | Electrostatic fields only |
| B. | Electrodynamic fields only |
| C. | Neither electrostatic fields nor electro-dynamic fields |
| D. | Both electrostatic fields and electro-dynamic fields |
| Answer» B. Electrodynamic fields only | |
| 689. |
All poles and zeros of a driving point immittance function of an L-C network |
| A. | should lie on the jω axis |
| B. | should lie on the +ve real axis |
| C. | should lie on the - ve real axis |
| D. | can lie anywhere in s-plane |
| Answer» B. should lie on the +ve real axis | |
| 690. |
The amplitude modulated wave is given by __________ e = 25(1 + 0.7 cos 5000t - 0.3 cos 1000t) x sin 5 x 106t The amplitude of carrier and sideband frequencies in magnitudes are |
| A. | 25, 0.7, 0.3 |
| B. | 25, 0.7, - 0.3 |
| C. | 24, 17.5, 7.5 |
| D. | 25, 8.75, 3.75 |
| Answer» E. | |
| 691. |
Maxwell's equations establish the relationship between , , and at any point in a continuous medium. When we move from one medium to another, then which of the following statement/statements is/are correct? |
| A. | At the boundary separating the two media, the tangential components of and are continuous. |
| B. | At the boundary separating the two media, the tangential components of are continuous |
| C. | If there are surface charges present on the boundary, then normal component of is continuous |
| D. | If there are no surface charges then normal component of is discontinuous. |
| Answer» B. At the boundary separating the two media, the tangential components of are continuous | |
| 692. |
For the BJT shown in figure, β = 50, the value of VCE is: |
| A. | 3.13 V |
| B. | 4.24 V |
| C. | 5.18 V |
| D. | none |
| Answer» E. | |
| 693. |
What is the period of the sinusoidal signal x(n) = 5 cos [0.2 pn]? |
| A. | 10 |
| B. | 5 |
| C. | 1 |
| D. | 0 |
| Answer» B. 5 | |
| 694. |
For a second order instrument, the optimum range of ξ (damping ratio), which gives good frequency response over a wide range of frequencies is |
| A. | 0.5 to 0.6 |
| B. | 0.6 to 0.7 |
| C. | 0.7 to 0.8 |
| D. | 0.8 to 1.0 |
| Answer» B. 0.6 to 0.7 | |
| 695. |
A delta modulation system is designed to operate at 3 times the Nyquist rate for a signal with a 3 KHz bandwidth. The quantization step size is 250 mv. The maximum amplitude of a 1 KHz input sinusoidal for which the delta modulator does not show slope overload is : |
| A. | 716.2 mV |
| B. | 500 mV |
| C. | 647.87 mV |
| D. | 400 mV |
| Answer» B. 500 mV | |
| 696. |
Which of the following statements is/are true for a good conductor of electricity? Its conductivity decreases with increasing temperature.Number of free electrons is around 1028 m-3.Its conductivity decreases with addition of impurities.It is a good conductor of heat also. |
| A. | 1, 2, 3 and 4 |
| B. | 1 only |
| C. | 2 and 3 only |
| D. | 3 and 4 only |
| Answer» B. 1 only | |
| 697. |
A λ/4 long high frequency transmission line is terminated into one impedance ZR. If Z0 be the characteristic impedance of the line, then input impedance Zin is |
| A. | ZoZR |
| B. | Z2R/Zo |
| C. | Z20/ZR |
| D. | Infinity |
| Answer» D. Infinity | |
| 698. |
An air-filled rectangular waveguide has dimensions 8cm x 10cm . The phase velocity of guided wave at frequency of 3 GHz for TE10 mode is |
| A. | 1.5 x 108 m/s |
| B. | 5.5 x 108 m/s |
| C. | 3.46 x 108 m/s |
| D. | 0.18 x 107 m/s |
| Answer» D. 0.18 x 107 m/s | |
| 699. |
For dielectric to dielectric interface with surface charge density, which of the following statements are true? Dn2 - Dn1 = rsEt1 = Et2En1 = En2 |
| A. | 1, 2 and 3 |
| B. | 1, 2 and 4 |
| C. | 1, 2 only |
| D. | 1, 4 only |
| Answer» C. 1, 2 only | |
| 700. |
A series RLC circuit has a resonance frequency of 1 kHz and a quality factor Q = 100. If each of R, L and C is doubled from its original value, the new Q of the circuit is |
| A. | 25 |
| B. | 50 |
| C. | 100 |
| D. | 200 |
| Answer» C. 100 | |