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.
| 251. |
Determine the correctness or otherwise of the following Assertion [a] and the Reason [r].Assertion : FETs are more suitable at the input stages compared to BJTsReason: A FET has lower output impedance than a BJT. |
| A. | Both [a] and [r] are true and [r] is the correct reason for [a] |
| B. | Both [a] and [r] are true but [r] is not the correct reason for [a] |
| C. | Both [a] and [r] are false |
| D. | Both [a] and [r] are true |
| Answer» C. Both [a] and [r] are false | |
| 252. |
If the z-transform of x(n) is given by then the filter it represents is __________ . |
| A. | low pass |
| B. | high pass |
| C. | band pass |
| D. | all pass |
| Answer» E. | |
| 253. |
Assertion (A): A fixed bias BJT circuit exhibits better performance as compared to a self bias BJT circuit.Reason (R): A fixed bias BJT circuit used less components as compared to a self bias BJT circuit. |
| 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. | |
| 254. |
Which of the following is not a conducting material? |
| A. | Copper |
| B. | Tungsten |
| C. | Germanium |
| D. | Platinum |
| Answer» D. Platinum | |
| 255. |
When transient and steady state response require improvement; a __________ is used. |
| A. | Lead compensator |
| B. | Lag - Lead compensator |
| C. | Lag compensator |
| D. | Integrator |
| Answer» C. Lag compensator | |
| 256. |
Which of the following is NOT associated with a p-n junction? |
| A. | Junction capacitance |
| B. | Charge Storage Capacitance |
| C. | Depletion Capacitance |
| D. | Channel Length Modulation |
| Answer» E. | |
| 257. |
The network is |
| A. | First order system and the pole |
| B. | Second order system of the two poles are |
| C. | Second order system of the poles is |
| D. | none of the above |
| Answer» C. Second order system of the poles is | |
| 258. |
Consider the following statements: Strictly speaking C supports 1-dimensional arrays only.An array element may be an array by itself.Array elements need not occupy contiguous memory locations. Which of the above statements is/are correct? |
| A. | 1 only |
| B. | 2 only |
| C. | 1 and 2 |
| D. | 2 and 3 |
| Answer» C. 1 and 2 | |
| 259. |
Why npn-transistors are preferred over pnp-transistors? |
| A. | Leakage current in npn-transistors is less than pnp-transistors |
| B. | Mobility of majority carrier in npra-transistors is greater than the mobility of majority carrier in pnp-transistors |
| C. | Bias voltage required in npn is less than in/wp-transistors |
| D. | Bias voltage required in npn is greater than in pnp-transistors |
| Answer» C. Bias voltage required in npn is less than in/wp-transistors | |
| 260. |
If f(Z) = c0 + c1z-1, then is given by |
| A. | 2pc1 |
| B. | 2p (1 + c0) |
| C. | 2pjc1 |
| D. | 2pj(1 + c0) |
| Answer» E. | |
| 261. |
In orthogonal BFSK. the energy of information bearing term is : |
| A. | the same as total transmitted energy |
| B. | one half of total transmitted energy |
| C. | one fourth of total transmitted energy |
| D. | None |
| Answer» B. one half of total transmitted energy | |
| 262. |
A lossless transmission line with air dielectric is 6 m long. What is the line length at 30 MHz? |
| A. | 1 wavelength long |
| B. | 0.5 wavelength long |
| C. | 0.6 wavelength long |
| D. | 0.25 wavelength long |
| Answer» D. 0.25 wavelength long | |
| 263. |
A matched filter has a frequency response given:The impulse response h(t) of the filter is : |
| A. | [δ(t) - δ(t - T] |
| B. | [u(t) - u(t - T)] |
| C. | [S gn(t) - Sgn(t - t)] |
| D. | [S gn(t) + Sgn(t - T)] |
| Answer» D. [S gn(t) + Sgn(t - T)] | |
| 264. |
What is the minimum value of VSWR that may exist on a transmission line? |
| A. | Less than zero |
| B. | Zero |
| C. | One |
| D. | 10 |
| Answer» D. 10 | |
| 265. |
In a conventional AM superhetrodyne receivers, the detectors employed to extract intelligence include |
| A. | Peak detectors |
| B. | Ratio detectors |
| C. | PLL |
| D. | Slope detectors |
| Answer» B. Ratio detectors | |
| 266. |
A speech signal, band limited to 4kHz and peak voltage varying between + 5V and - 5V is sampled at the Nyquist rate. Each sample is quantized and represented by 8 bits. Assuming the signal to be uniformly distributed between its peak values, the signal to noise ratio at the quantizer output is |
| A. | 156 dB |
| B. | 32 dB |
| C. | 48 dB |
| D. | 64 dB |
| Answer» D. 64 dB | |
| 267. |
The dominant mode in a rectangular wave-guide is |
| A. | TE01 |
| B. | TM01 |
| C. | TE10 |
| D. | TM11 |
| Answer» D. TM11 | |
| 268. |
Two identical NMOS transistors M1 and M2 are connected as shown below. Vbias is chosen so that both transistors are in saturation. The equivalent gm of the pair is defined to be at constant VoutThe equivalent gm of the pair is |
| A. | the sum of individual gm's of the transistors |
| B. | the product of individual gm's of the transistors |
| C. | nearly equal to the gm of M1 |
| D. | nearly equal to gm / g0 of M2 |
| Answer» D. nearly equal to gm / g0 of M2 | |
| 269. |
The value of the integral of the function g(x, y) = 4x3 + 10y4 along the straight line segment from the point (0, 0) to the point (1, 2) in the x-y plane is |
| A. | 33 |
| B. | 35 |
| C. | 40 |
| D. | 56 |
| Answer» B. 35 | |
| 270. |
Consider the following statements regarding the class-B power amplifiers (Complementary symmetry type): The efficiency of the amplifier is higher than that of class-A amplifierThe power output is lowCrossover distortion is presentThe standby power dissipation is absent. Which of the above statements are correct? |
| A. | 1, 2 and 3 |
| B. | 1, 2 and 4 |
| C. | 1, 3 and 4 |
| D. | 2, 3 and 4 |
| Answer» D. 2, 3 and 4 | |
| 271. |
A white noise X(t) with two-sided power spectral density 1 x 10-10 W/Hz is input to a filter whose magnitude squared response is shown below.The power of the output process Y(t) is given by |
| A. | 5 x 10-7W |
| B. | 1 x 10-6W |
| C. | 2 x 10-6W |
| D. | 5 x 10-6W |
| Answer» C. 2 x 10-6W | |
| 272. |
A square in which each (i, j)th element of matrix is equal to the negative of the conjugate complex of (j, i)th element, is called |
| A. | Hermitian matrix |
| B. | Skew symmetric matrix |
| C. | Conjugate anti-symmetric matrix |
| D. | Skew-Hermitian matrix |
| Answer» E. | |
| 273. |
NMOS devices have __________ switching speeds and __________ on-state resistance; as compared with PMOS devices. |
| A. | slower, higher |
| B. | faster, lower |
| C. | faster, higher |
| D. | slower, lower |
| Answer» C. faster, higher | |
| 274. |
convert into spherical co-ordinates. |
| A. | A = 2 sinθ[sinθ tanΦa r + sinΦa θ + a Φ] |
| B. | A = 2 sinΦ[sinΦ tanΦa r + sinΦa θ + a Φ] |
| C. | A = 2 sinΦ[sinΦ tanΦa r - sinΦa θ - a Φ] |
| D. | none of these |
| Answer» E. | |
| 275. |
Consider the following two statements about the internal conditions in an n-channel MOSFET operating in the active regionS1: The inversion charge decreases from source to drainS2: The channel potential increases from source to drainWhich of the following is correct? |
| A. | Only S2 is true |
| B. | Both S1 and S2 are false |
| C. | Both S1 and S2 are true, but S2 is not a reason for S1 |
| D. | Both S1 and S2 are true, and S2 is a reason for S1 |
| Answer» E. | |
| 276. |
A 300 MHz plane EM wave is propagating in free space. The wave is incident normally on an infinite copper slap. The antenuation constant for the wave is (σcopper = 5.8 x 107 mho/ m). The skin depth is |
| A. | 0.005 x 10-3 m |
| B. | 0.0038 x 10-3m |
| C. | 0.0028 x 10-3 m |
| D. | 0.0024 x 10-3 m |
| Answer» C. 0.0028 x 10-3 m | |
| 277. |
Assertion (A): An unbiased p-n junction develops a built-in potential at the junction with the n-side positive and the p-side negative.Reason (R): The p-n junction behaves as a battery and supplies current to a resistance connected across its terminals. |
| 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 | |
| 278. |
Find the Fourier transform of the half cosine pulse as shown below : |
| A. | 0.5 {sin c [0.25(f - 1)] + sin c [2.5(f + 1)]} |
| B. | 0.5 {sin c [0.5(f - 1)] + sin c [0.5(f + 1)]} |
| C. | 0.25 {sin c [0.25(f - 1)] + sin c [0.25 (f - 1)]} |
| D. | 0.25 {sin c [0.5(f - 1)] + sin c [0.5(f - 1)]} |
| Answer» C. 0.25 {sin c [0.25(f - 1)] + sin c [0.25 (f - 1)]} | |
| 279. |
With regard to a transmission line, which of the following statements is correct? |
| A. | Any impedance repeats itself every 1/4 on the Smith chart. |
| B. | The S.W.R. = 2 circle and the magnitude of reflection coefficient = 0.5 circle coincide on the Smith chart. |
| C. | At any point on a transmission line, the current reflection coefficient is the reciprocal of the voltage reflection coefficient. |
| D. | Matching eliminates the reflected wave between the source and the matching device location. |
| Answer» D. Matching eliminates the reflected wave between the source and the matching device location. | |
| 280. |
A rectangular wave guide is designed to propagate at the dominant mode TE10 at a frequency of 5 GHz. The cut-off frequency is 0.8 of signal frequency. The ratio of the guide width to height is 2. The dimensions of the guide are |
| A. | 3.75 cm, 1.875 cm |
| B. | 4 cm, 2 cm |
| C. | 8 cm, 4 cm |
| D. | 2.54 cm, 1.27 cm |
| Answer» B. 4 cm, 2 cm | |
| 281. |
Let f(A, B) = A ‚äï B; then the simplified form of the function f(f(x ‚äï y, z)w) is |
| A. | (x ‚äï y ‚äï z)w |
| B. | x ‚äï y ‚äï z ‚äï w |
| C. | (x ‚äï y ‚äï z) + w |
| D. | none of these |
| Answer» E. | |
| 282. |
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.Which of the following statements is true? |
| A. | G(s) is an all-pass filter |
| B. | G(s) has a zero in the right-half plane |
| C. | G(s) is the impedance of a passive network |
| D. | G(s) is marginally stable |
| Answer» D. G(s) is marginally stable | |
| 283. |
Which of the following measurements can be done using a counter? Pulse durationInterval between two pulses Amplitude of the pulse Rise time of a pulse Select the correct answer from the codes given below: |
| A. | 1 and 2 |
| B. | 2 and 3 |
| C. | 1 and 4 |
| D. | 2 and 4 |
| Answer» B. 2 and 3 | |
| 284. |
A radio wave is incident on a layer of ionosphere at an angle of 30° with the vertical. If the critical frequency is, 1.2 MHz, the maximum usable frequency is |
| A. | 1.2 MHz |
| B. | 2.4 MHz |
| C. | 0.6 MHz |
| D. | 1.386 MHz |
| Answer» E. | |
| 285. |
Assertion (A): When all inputs of a NAND-gate are shorted to get a one input, one output gate, it becomes an inverter.Reason (R): When all inputs of a NAND-gate are at logic 'O' level, the output is at logic 'I' level. |
| 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» C. A is true but R is false | |
| 286. |
Open loop transfer function of a system isThe phase cross over frequency ωc is |
| A. | |
| B. | 1 |
| Answer» C. | |
| 287. |
In the following limiter circuit, an input voltage V1 = 10 sin 100pt applied. Assume that the diode drop is 0.7 V when it is forward biased. The zener breakdown voltage is 6.8 VThe maximum and minimum values of the output voltage respectively are |
| A. | 6.1 V, -0.7 V |
| B. | 0.7 V, -7.5 V |
| C. | 7.5 V, -0.7 V |
| D. | 7.5 V, -7.5 V |
| Answer» D. 7.5 V, -7.5 V | |
| 288. |
For a given transfer function: Damping ratio is: |
| A. | 0.707 |
| B. | 0.695 |
| C. | 1.414 |
| D. | 0.798 |
| Answer» B. 0.695 | |
| 289. |
With respect to the differential amplifier configuration shown below, the differential gain Ad will be Rc = 4.7 KΩRE = 2.7 KΩhfe = 100hie = 1 KΩRS = 100 Ω |
| A. | 273.63 |
| B. | 213.63 |
| C. | 113.63 |
| D. | 233.63 |
| Answer» C. 113.63 | |
| 290. |
Input and output impedance with feedback for voltage series feedback having A = -200, R1 = 10 kΩ, R0 = 50 kΩ and feedback factor β = -0.2 will be |
| A. | 410 kΩ, 2050 kΩ |
| B. | 410 kΩ, 1.219 kΩ |
| C. | ≈ 0.243 kΩ, 2050 kΩ |
| D. | ≈ 0.24 kΩ, 1.219 kΩ |
| Answer» C. ‚âà 0.243 kŒ©, 2050 kŒ© | |
| 291. |
The following properties are associated with ferroelectric materials: Its susceptibility is negative.The susceptibility is expressed aswhere c is the Curie constant and Tc is the Curie temperature.It has permanent dipoles oriented randomly. Which of the above statements is/are correct? |
| A. | 1 only |
| B. | 1 and 3 |
| C. | 2 only |
| D. | 1, 2 and 3 |
| Answer» D. 1, 2 and 3 | |
| 292. |
The current i(t), though a 10 Ω resistor in series with an inductance, is given by i(t) = 3 + 4 sin (10t + 45°) + 4 sin (300t + 60°) Amperes. The RMS value of the current and the power dissipated in the circuit are |
| A. | 41 A, 410 W, respectively |
| B. | 35 A, 350 W, respectively |
| C. | 5 A, 250 W, respectively |
| D. | 11 A, 1210 W, respectively |
| Answer» B. 35 A, 350 W, respectively | |
| 293. |
A switch tail ring counter is made by using a single D FF. The resulting circuit is a |
| A. | SR FF |
| B. | JK FF |
| C. | D FF |
| D. | T FF |
| Answer» D. T FF | |
| 294. |
The transfer function of a controller is given as Kp + Kd.s + where Kp, Kd and Ki are constants. What type of controller is this? |
| A. | Proportional |
| B. | Proportional plus derivative |
| C. | Proportional plus integral |
| D. | Proportional plus integral plus derivative |
| Answer» E. | |
| 295. |
For the circuit shown in the following figure, transistors M1 and M2 are identical NMOS transistors. Assume that M2 is in saturation and the output is unloadedThe current Ix is related to Ibias as |
| A. | Ix = Ibias + Is |
| B. | Ix = Ibias |
| C. | Ix = Ibias - Is |
| Answer» C. Ix = Ibias - Is | |
| 296. |
For the given phase lead network, the maximum possible phase lead is |
| A. | sin-1 |
| B. | 30° |
| C. | 45° |
| D. | 60° |
| Answer» C. 45¬∞ | |
| 297. |
Transfer function of a certain system is: The approximate 2% settling time for unit step input is |
| A. | 2 sec |
| B. | 4 sec |
| C. | 6 sec |
| D. | 8 sec |
| Answer» C. 6 sec | |
| 298. |
For a periodic signal with finite number of discontinuities in each period, at isolated points of discontinuity the series converges to __________ . |
| A. | difference value of signal on either side of discontinuity |
| B. | highest value of signal on either side of discontinuity |
| C. | average value of signal on either side of discontinuity |
| D. | sum of value of signal on either side of discontinuity |
| Answer» D. sum of value of signal on either side of discontinuity | |
| 299. |
Consider the equation s2 + 2s + 2 + K(s + 2) = 0. Where do the roots of this equation break on the root loci plot? |
| A. | -3.414 |
| B. | -2.414 |
| C. | -1.414 |
| D. | -0.414 |
| Answer» B. -2.414 | |
| 300. |
Which of the following introduces mode partition noise? |
| A. | Coaxial line |
| B. | Waveguide |
| C. | Fibre transmission line |
| D. | Both coaxial line and waveguide |
| Answer» C. Fibre transmission line | |