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.
| 401. |
In the circuit below, the diode is ideal. The voltage V is given by |
| A. | min(Vi, 1) |
| B. | max(Vi, 1) |
| C. | min (-Vi, 1) |
| D. | max (-Vi, 1) |
| Answer» E. | |
| 402. |
Consider the following statements:For a 10 m long common power line connecting a switch to a light bulb It is a distributed circuit.Time delay for propagation through it is negligible.It is the form of a shielded coaxial cable of circular cross-section.As the intensity of the lamp varies, input impedance of this line also changes. Which of the above statements is/are correct? |
| A. | 1 only |
| B. | 1 and 2 |
| C. | 2 and 3 |
| D. | 2 and 4 |
| Answer» D. 2 and 4 | |
| 403. |
Find RAB |
| A. | 2 Ω |
| B. | 1.5 Ω |
| C. | 3 Ω |
| D. | None of the above |
| Answer» B. 1.5 Œ© | |
| 404. |
A point charge of 6 μC is located at the origin, uniform line charge density of 180 nC/m of 8 m length lies along the x axis and a uniform sheet of charge equal to 25 nC/m2 of area p x 42 lies in the z = 0 plane. Calculate total electric flux leaving the surface of sphere of 4 m radius centered at origin. |
| A. | 86.97 μC |
| B. | 8.697 nC |
| C. | 8.697 μC |
| D. | 86.97 nC |
| Answer» D. 86.97 nC | |
| 405. |
Find resistance RB to bring transistor to threshold of saturation (VCB = 0), VBE = 0.7 V, a = 0.96 |
| A. | 1.5 KΩ |
| B. | 15 KΩ |
| C. | 10 KΩ |
| D. | 1 KΩ |
| Answer» B. 15 KŒ© | |
| 406. |
Two products are sold from a vending machine, which has two push buttons P1 and P2. When a button is pressed, the price of the corresponding product is displayed in a 7-segment display. If no buttons are pressed, '0' is displayed, signifying 'Rs' .0'. If only P1 is pressed, '2' is displayed, signifying 'Rs. 2'.If only P2 is pressed, '5' is displayed, signifying 'Rs. 5'.If both P1 and P2 are pressed, 'E' is displayed, signifying 'Error'. The names of the segments in the 7-segment display, and the glow of the display for '0', '2', '5' and 'E', are shown below.Consider push button pressed/not pressed is equivalent to logic 1/ 0 respectivelya segment a to g are considered as functions of P1 and P2, then which of the respectively. If segments a to g are considered as functions of P1 and P2, then which of the following is correct? |
| A. | g = P1 + P2, d = c + e |
| B. | g = P1 + P2, d = c + e |
| C. | g = P1 + P2, e = b + c |
| D. | g = P1 + P2, e = b + c |
| Answer» C. g = P1 + P2, e = b + c | |
| 407. |
Which one of the following is a regulated power supply? |
| A. | IC 555 |
| B. | IC 844 |
| C. | IC 3080 |
| D. | IC 723 |
| Answer» E. | |
| 408. |
An image uses 512 x 512 picture elements. Each of the picture elements can take any of the 8 distinguishable intensity levels. The maximum entropy in the above image will be |
| A. | 2097152 bits |
| B. | 648 bits |
| C. | 786432 bits |
| D. | 144 bits |
| Answer» D. 144 bits | |
| 409. |
For real and odd signals, the Fourier series coefficient ak is __________ . |
| A. | purely imaginary and even |
| B. | purely real and even |
| C. | purely imaginary and odd |
| D. | purely real and odd |
| Answer» D. purely real and odd | |
| 410. |
A system described by the following differential equation is initially at rest. For input x(t) - 2u(t), the output y(t) is : |
| A. | (1 - 2e-t + e -2t) |
| B. | (1 + 2e-t - 2e -2t)u(t) |
| C. | (0.5 + e-t + 1.5e -2t)u(t) |
| D. | (0.5 + 2e-t + 2e -2t)u(t) |
| Answer» B. (1 + 2e-t - 2e -2t)u(t) | |
| 411. |
Which of the following conditions should be satisfied to call an astable multivibrator circuit using discrete components as a digital circuit? A flip-flop is always a digital circuit. Only when we assign 1 and 0 to the high and low levels of the output, a flip-flop is called a digital circuit. Only if the power, supply voltage is maintained at + 5 V or - 5 V, it is called a digital circuit. Only if it is in IC form, following the technology of IC manufacture, it is called a digital circuit.Select the correct answer from the codes given below: |
| A. | 1 only |
| B. | 2 and 3 |
| C. | 2 only |
| D. | 3 and 4 |
| Answer» B. 2 and 3 | |
| 412. |
Silicon is doped with boron to a concentration of 4 x 1017 atoms/cm3. Assuming the intrinsic carrier concentration of silicon to be 1.5 x 1010/cm3 and the value of to be 25mV at 300K. Compared to undoped silicon, the Fermi level of doped silicon |
| A. | goes down by 0.13 eV |
| B. | goes up by 0.13 eV |
| C. | goes down by 0.427 eV |
| D. | goes up by 0.427 eV |
| Answer» D. goes up by 0.427 eV | |
| 413. |
If V = 4 in the figure, the value of IS is given by, |
| A. | 0.25 |
| B. | 5/2 A |
| C. | 0 |
| D. | None of these |
| Answer» B. 5/2 A | |
| 414. |
If the open-loop transfer function is a ratio of a numerator polynomial of degree 'm' and a denominator polynomial of degree 'n', then the integer (n - m) represents the number of: |
| A. | breakaway points |
| B. | unstable poles |
| C. | separate root loci |
| D. | asymptotes |
| Answer» E. | |
| 415. |
Consider a control system shown in given figure. For slight variation in G, the ratio of open loop sensitivity to closed loop sensitivity will be given by |
| A. | 1 : (1 + GH) |
| B. | 1 : (1 + GH)- 1 |
| C. | 1 : (1 - GH) |
| D. | 1 : (1 - GH)- 1 |
| Answer» C. 1 : (1 - GH) | |
| 416. |
A communication channel with AWGN operating at a signal to noise ratio SNR >> 1 and bandwidth B has capacity C1. If the SNR is doubled keeping B constant, the resulting capacity C2 is given by |
| A. | C2 ≈ 2C1 |
| B. | C2 ≈ C1 + B |
| C. | C2 ≈ C1 + 2B |
| D. | C2 ≈ C1 + 0.3B |
| Answer» C. C2 ‚âà C1 + 2B | |
| 417. |
Assertion (A): Capacitance of a solid conducting spherical body of radius 'a' is given by 4 pε0a in free space.Reason (R): Δ x H = jωεE + J. |
| 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 | |
| 418. |
A 16 bit counter type ADC uses 1 MHz clock then its maximum conversion time is __________ . |
| A. | 16 μs |
| B. | 15 ms |
| C. | 6.6 ms |
| D. | 66 ms |
| Answer» E. | |
| 419. |
A certain system has transfer function a is a parameter. Consider the standard negative unity feedback configuration as shown below.Which of the following statements is true? |
| A. | The closed loop system in never stable for any value of a a |
| B. | For some positive values of a, the closed loop system is stable, but not for all positive values |
| C. | For all positive values of a, the closed loop system is stable |
| D. | The closed loop system is stable for all values of a, both positive and negative |
| Answer» D. The closed loop system is stable for all values of a, both positive and negative | |
| 420. |
Find the electric charge required on the earth and moon to balance their gravitational attraction if the charge on the earth is 10 times that on the moon. |
| A. | 1.73 TC |
| B. | 17.3 GC |
| C. | 17.3 TC |
| D. | 1.73 GC |
| Answer» D. 1.73 GC | |
| 421. |
The magnitude plot of a composite signal x(t) = e3jt + e4jt is __________ . |
| A. | Half wave rectified sinusoid |
| B. | Full wave rectified sinusoid |
| C. | Exponentially increasing sinusoid |
| D. | Exponentially decreasing sinusoid |
| Answer» C. Exponentially increasing sinusoid | |
| 422. |
Which of the following transducers requires a high input impedance preamplifier for proper measurements? |
| A. | Thermocouple |
| B. | Piezoelectric |
| C. | Thermistor |
| D. | L.V.D.T |
| Answer» C. Thermistor | |
| 423. |
. The signal is __________ . |
| A. | periodic for t > 0 |
| B. | non-periodic |
| C. | periodic for t < 0 |
| D. | depends on t |
| Answer» C. periodic for t < 0 | |
| 424. |
What happens when a paramagnetic material is heated above Curie temperature? |
| A. | It becomes diamagnetic |
| B. | It becomes nonmagnetic |
| C. | It becomes ferromagnetic |
| D. | It becomes anti-ferromagnetic |
| Answer» B. It becomes nonmagnetic | |
| 425. |
A germanium diode has a reverse saturation current of 30 μA at 125°C and forward current of 1 mA at a forward potential of 0.8 V and the reverse potential is 0.6 V What are its dynamic forward and reverse resistance at this temperature. |
| A. | 10.7 Ω, 70 kΩ |
| B. | 34 Ω, 20 kΩ |
| C. | 80 Ω, 20 kΩ |
| D. | 800 Ω, 40 kΩ |
| Answer» C. 80 Œ©, 20 kŒ© | |
| 426. |
If , then y has a |
| A. | maximum at x = e |
| B. | minimum at x = e |
| C. | maximum at x = e-1 |
| D. | minimum at x = e-l |
| Answer» B. minimum at x = e | |
| 427. |
ωH = |
| A. | 108 rad/sec |
| B. | 104 rad/sec |
| C. | 102 rad/sec |
| D. | 10 rad/sec |
| Answer» B. 104 rad/sec | |
| 428. |
Which of the following describe the correct properties of an emitter follower circuit? It is a voltage series feedback circuit.It is a current series feedback circuit.Its voltage gain in less than unity.Its output impedance is very low. Select the correct answer from the codes given below: |
| A. | 1, 3 and 4 |
| B. | 2, 3 and 4 |
| C. | 2 and 3 only |
| D. | 2 and 4 only |
| Answer» B. 2, 3 and 4 | |
| 429. |
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 stable reading of the LED display is |
| A. | 6 |
| B. | 7 |
| C. | 12 |
| D. | 13 |
| Answer» E. | |
| 430. |
The following Variable Entered Map (VEM) represents which of the following function: |
| A. | f(A, B, C, D) = ∑(1, 2, 3, 4, 7, 8, 9, 14, 15) + Φ(3, 5, 12, 13) |
| B. | f(A, B, C, D) = ∑(1, 2, 4, 8, 10, 8, 13, 15) + Φ(3, 6, 12, 14) |
| C. | f(A, B, C, D) = ∑(1, 2, 4, 7, 8, 10, 13, 15) + Φ(6, 12, 13) |
| D. | f(A, B, C, D) = ∑(1, 2, 4, 7, 8, 9, 12, 13) + Φ(3, 5, 14, 15) |
| Answer» E. | |
| 431. |
For the collector-feedback amplifier shown below the voltage gain Av will be __________ . |
| A. | -113.07 |
| B. | -103.07 |
| C. | -107.07 |
| D. | -93 |
| Answer» C. -107.07 | |
| 432. |
A periodic voltage has following values for equal time intervals changing suddenly from one value to next : 0, 5, 10, 20, 50, 60, 50, 20, 10, 5, 0, - 5, - 10 etc.RMS value of the waveform is : |
| A. | 31 v |
| B. | 32 v |
| C. | insufficient data |
| D. | none of these |
| Answer» B. 32 v | |
| 433. |
A discrete random variable X takes values from 1 to 5 with probabilities as shown in the table. A student calculates the mean of X and 3.5 and her teacher calculates the variance of X as 1.5. Which of the following statements is true? |
| A. | Both the student and the teacher are right |
| B. | Both the student and the teacher are wrong |
| C. | Both the student is wrong but the teacher is right |
| D. | The student is right but the teacher is wrong |
| Answer» C. Both the student is wrong but the teacher is right | |
| 434. |
Average power for δ(t)dt signal is __________ . |
| A. | |
| B. | 1 |
| C. | 0 |
| Answer» B. 1 | |
| 435. |
In 8085 microprocessor system, what will be the total delay provided by the following loop.MVI A, 11HLXI B, 12FFHDelay: DCX BXTHLNOPXRA BJNZ Delaywhere system clock is operating at 3 MHz. |
| A. | 3.154 msec |
| B. | 3.514 msec |
| C. | 2.644 msec |
| D. | 3.166 msec |
| Answer» B. 3.514 msec | |
| 436. |
The current i(t) through a 10 Ω resistor in series with an inductance is given by i(t) = 3 + 4 sin (100t + 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» D. 11 A, 1210 W respectively | |
| 437. |
In 8085 microprocessor based system running at 3 MHz clock frequency what should be the minimum pulse width of the INTR signal, so that it is recognized successfully? |
| A. | 0.33 μs |
| B. | 0.666 μs |
| C. | 5.8 μs |
| D. | none of these |
| Answer» D. none of these | |
| 438. |
A small signal source vi(t) = A cos 20t + B sin106t is applied to a transistor amplifier as shown below. The transistor has β = 150 and hie = 3 kΩ. Which expression best approximates V0(t) |
| A. | v0(t) = -1500 (A cos 20t + B sin 106t) |
| B. | v0(t) = -150 (A cos 20t + B sin 106t) |
| C. | v0(t) = -1500 B sin 106t |
| D. | V0(t) = -1500 sin 106t |
| Answer» E. | |
| 439. |
The load end of a quarter wave transformer gets disconnected thereby causing an open-circuited load. What will be the input impedance of the transformer? |
| A. | Zero |
| B. | Infinite |
| C. | Finite and Positive |
| D. | Finite and Negative |
| Answer» B. Infinite | |
| 440. |
For a Gaussian process, auto-correlation also implies |
| A. | statistical dependence |
| B. | statistical independence |
| C. | ergodic process |
| D. | none of the above |
| Answer» C. ergodic process | |
| 441. |
Find the number of loop equation and number of possible trees for the given graph. |
| A. | 7, 2097152 |
| B. | 7, 262144 |
| C. | 7.5764801 |
| D. | 6, 823543 |
| Answer» C. 7.5764801 | |
| 442. |
Electric dipole is located at origin in a medium with εr = 6, has a moment P = (4ax - 2ay + az ) nC. Then potential at (2, 4, 4) is: |
| A. | 0.062 |
| B. | 0.027 |
| C. | 0.042 |
| D. | 0.072 |
| Answer» C. 0.042 | |
| 443. |
A memory system of size 16 K bytes is required to be designed using memory chips having 12 address lines and 4 data lines-each. The number of such chips required to design and the memory system is : |
| A. | 2 |
| B. | 4 |
| C. | 8 |
| D. | 16 |
| Answer» D. 16 | |
| 444. |
Who developed the concept of time varying electric field producing a magnetic field? |
| A. | Gauss |
| B. | Faraday |
| C. | Hertz |
| D. | Maxwell |
| Answer» C. Hertz | |
| 445. |
The system with given pole-zero diagram is __________ |
| A. | Causal |
| B. | Anti-causal |
| C. | Both sided |
| D. | Cannot be determined |
| Answer» E. | |
| 446. |
If the function A, B are A = R + PQ + RS B = PQRS + PQRS + PQRS Which of the following is true? |
| A. | A = B |
| B. | A = B |
| C. | no direct relation between A and B |
| D. | insufficient data |
| Answer» C. no direct relation between A and B | |
| 447. |
Consider a silicon p-n junction at room temperature having the following parameters:Doping on the n-side = 1 x 1017 cm-3Depletion width on the n-side = 0.1 μmDepletion width on the p-side = 1.0 μmIntrinsic carrier concentration = 1.4 x 1014F. cm-1.Thermal voltage = 26mVPermittivity of free space = 8.85 x 10-14F. cm-1.Dielectric constant of silicon = 12. The peak electric field in the device is |
| A. | 0.15 MV.com-1, directed from p-region to n-region |
| B. | 0.15 MV.com-1, directed from n-region to p-region |
| C. | 1.80 MV.com-1, directed from p-region to n-region |
| D. | 1.80 MV.com-1, directed from n-region to p-region |
| Answer» C. 1.80 MV.com-1, directed from p-region to n-region | |
| 448. |
Which device can detect the presence of both forward and backward waves in a waveguide? |
| A. | Filter |
| B. | Detector |
| C. | Directional coupler |
| D. | Magic T |
| Answer» D. Magic T | |
| 449. |
Power gain of antenna equals directive gain in VHF and UHF range if and only if efficiency of the antenna is __________ . |
| A. | 0.25 |
| B. | 0.5 |
| C. | 0.75 |
| D. | 1 |
| Answer» E. | |
| 450. |
Using 4-bit numbers (n = 4) if k = (0011)2 how is k expressed in 2's complement. |
| A. | (1011)2 |
| B. | (1101)2 |
| C. | (1100)2 |
| D. | (0101)2 |
| Answer» C. (1100)2 | |