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.
| 701. |
A MOSFET has a threshold voltage of 1 V and oxide thickness of 500 x 10-8 [εr = 3.9; ε0 = 8.85 x 10-14 F/cm, q = 1.6 x 10-19 c]. The region under the gate is ion implanted for threshold voltage tailoring. The base and type of impant required to shift threshold voltage to - 1 V are __________ . |
| A. | 8.6 x 1011/cm2, p-type |
| B. | 8.6 x 1011/cm2, n-type |
| C. | 0.86 x 109/cm2, p-type |
| D. | 1.02 x 1012/cm2, n-type |
| Answer» B. 8.6 x 1011/cm2, n-type | |
| 702. |
Consider a random noise voltage which has a uniform density function as shown in the figure and is known to be white.If the noise is the first quantized into 0.1 V steps, starting at 0 V level, and then readings made of 10 per second. The information content of the reading is : |
| A. | 2 bits/reading |
| B. | 5 bits/reading |
| C. | 10 bits/reading |
| D. | none of these |
| Answer» C. 10 bits/reading | |
| 703. |
In a J-K FF we have J = Q and K = 1. Assuming the FF was initially cleared and then clocked for 6 pulses, the sequence at the Q output will be |
| A. | 10000 |
| B. | 11001 |
| C. | 10010 |
| D. | 10101 |
| Answer» E. | |
| 704. |
Which of the following is/are correct statement(s)? Bus is a group of wires carrying information.Bus is needed to achieve reasonable speed of operation.Bus can carry data or address.A bus can be shared by more than one device. Select the correct answer from the codes given below |
| A. | 1 only |
| B. | 1 and 2 only |
| C. | 2, 3 and 4 only |
| D. | 1, 2, 3 and 4 |
| Answer» E. | |
| 705. |
X(t) is a stationary process with the power spectral density Sx(f) > 0 for all f. The process is passed through a system shown below.Let Sy, (f) be the power spectral density Y(t). Which one of the following statements is correct? |
| A. | Sy(f) > 0 for all f |
| B. | Sy(f) = 0 for |f| > 1kHz |
| C. | Sy(f) = 0 for f = nf0, f0 = 2kHz, n any integer |
| D. | Sy(f) = 0 for f = (2n + 1)f0 = 1 kHz, n any integer |
| Answer» E. | |
| 706. |
A surface charge density of 8 nc/m2 is present on a plane x = z. A line charge density of 30 nC/m is present on line x = 1, y = 2 Find VAB for points A(3, 4, 0) and B(4, 0, 1) |
| A. | 583.38 V |
| B. | 58.338 V |
| C. | 583.38 mV |
| D. | 58.338 mV |
| Answer» B. 58.338 V | |
| 707. |
Which of the following is a solution to the differential equation ? |
| A. | x(t) = 3e-t |
| B. | x(t) = 2e-3t |
| C. | |
| Answer» C. | |
| 708. |
Two discrete time systems with impulse responses h1[n] = δ[n - 1] and h2[n] = δ[n - 2] are connected in cascade. The overall impulse response of the cascaded system is |
| A. | δ[n - 1] + δ[n - 2] |
| B. | δ[n - 4] |
| C. | δ[n - 3] |
| D. | δ[n - 1] + δ[n - 2] |
| Answer» D. Œ¥[n - 1] + Œ¥[n - 2] | |
| 709. |
If the potential functions V1 and V2 satisfy Laplace's equation within a closed region and assume the same values on its surface, then which of the following is correct? |
| A. | V1 and V2 are identical |
| B. | V1 is inversely proportional to V2 |
| C. | V1 has the same direction as V2 |
| D. | V1 has the same magnitude as V2 but has different direction |
| Answer» B. V1 is inversely proportional to V2 | |
| 710. |
A silicon wafer has 100 nm of oxide it and is inserted in a furnace at a temperature above 1000°C for further oxidation in dry oxygen. The oxidation rate |
| A. | is independent of current oxide thickness and temperature |
| B. | is independent of current oxide thickness but depends on temperature |
| C. | slows down as the oxide grows |
| D. | is zero as the existing oxide prevents further oxidation |
| Answer» E. | |
| 711. |
In 8085 microprocessor, the interrupt enable flip-flop is reset by |
| A. | DI instruction only |
| B. | system RESET only |
| C. | interrupt acknowledgment only |
| D. | all of the above |
| Answer» E. | |
| 712. |
For a series resonant circuit at low frequency circuit impedance is __________ and at high frequency circuit impedance is __________ Fill in the blanks respectively |
| A. | capacitive, inductive |
| B. | inductive, capacitive |
| C. | resistive, inductive |
| D. | capacitive, resistive |
| Answer» B. inductive, capacitive | |
| 713. |
Consider the following statements: Taking 2's complement is equivalent to sign change.In the 2's complement representation the most significant bit (MSB) is zero for a positive number.In a 4 bit binary representation of a binary number A, A + 1's complement of A = 24. Which of the above statements are correct? |
| 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 | |
| 714. |
The electric field of uniform plane wave is given by E = 20 sin (2 p x 108t- pz) x + 20 cos (2 p x 108t - pz) y. The polarization of wave is |
| A. | Elliptical, left handed |
| B. | Circular, left handed |
| C. | Elliptical, right handed |
| D. | Circular, right handed |
| Answer» C. Elliptical, right handed | |
| 715. |
As the temperature increases the mobility of electrons __________ . |
| A. | decreases because the number of carries increases with increased collisions |
| B. | increases because the number of carries decreases with decreased collisions |
| C. | remains same |
| D. | none of the above |
| Answer» B. increases because the number of carries decreases with decreased collisions | |
| 716. |
The equivalent form of the logical expression ABC + A BC + ABC + ABC + AB C is |
| A. | C + (A ‚äï B) |
| B. | (A + B + C)(A + B + C) |
| C. | (A + B + C)(A + B + C)(A + B + C) |
| D. | (A + B + C)(A + B + C)(A + B + C) |
| Answer» E. | |
| 717. |
The analog signal given below is sampled at 1200 samples per second. m(t) = 2 sin 120 pt + 3 sin 240 pt + 4 sin 360 pt + 5 sin 480 pt + 6 sin 600 pt + 7 sin 720 pt. The folding (maximum) frequency is __________ . |
| A. | 300 Hz |
| B. | 360 Hz |
| C. | 600 Hz |
| D. | 480 Hz |
| Answer» D. 480 Hz | |
| 718. |
For the circuit, let us assume that R = 1 Ω, L = 10-3 H, and V(t) = 10 cos (1000t + 30°)V and the differential equation for I(t) is given by |
| A. | 7.07 cos (1000t + 15°) A |
| B. | 70.7 cos (1000t - 30°) A |
| C. | 7.07 cos (1000t - 15°) A |
| D. | 7.07 cos (1000t + 15°) A |
| Answer» D. 7.07 cos (1000t + 15¬∞) A | |
| 719. |
Which of the following flip-flop is used as a latch? |
| A. | J K flip-flop |
| B. | R S flip-flop |
| C. | T flip-flop |
| D. | D flip-flop |
| Answer» E. | |
| 720. |
The switching expression corresponding to :f(A, B, C, D)= ‚àë(0, 3, 4, 7, 8) + (10, 11, 12, 14, 15) is: |
| A. | C D + B C |
| B. | C ‚äô D |
| C. | C ‚äï D |
| D. | CD |
| Answer» C. C ‚äï D | |
| 721. |
The Hilbert transform of cos ω1t + sin ω2t is |
| A. | sin ω1t + cos ω2t |
| B. | sin ω1t - cos ω2t |
| C. | cos ω1t - cos ω2t |
| D. | sin ω1t + sin ω2t |
| Answer» C. cos œâ1t - cos œâ2t | |
| 722. |
Hall coefficient RH is directly proportional to the charge densityRH depends upon type of the semiconductor material (n - type or p - type)Hall co-efficient RH is directly proportional to hall voltage VH From the above statements which are the false statements? |
| A. | I only |
| B. | II only |
| C. | III only |
| D. | all of the above |
| Answer» B. II only | |
| 723. |
The logic realized by the circuit shown in figure below is |
| A. | F = A - C |
| B. | F = A + C |
| C. | F = B ‚äô C |
| D. | F = B ‚äï C |
| Answer» C. F = B ‚äô C | |
| 724. |
Consider the following statements:In a microstrip line Wavelength , where eff is the effective dielectric constant and 1 is the free space wavelength.Electromagnetic fields exist partly in the air above the dielectric substrate and partly within the substrate itself.The effective dielectric constant is greater than the dielectric constant of the air.Conductor losses increase with decreasing characteristic impedance. Which of the above statements is/are correct? |
| A. | 1, 2 and 3 |
| B. | 1 and 2 only |
| C. | 2, 3 and 4 |
| D. | 2, 3 and 4 |
| Answer» B. 1 and 2 only | |
| 725. |
The open loop transfer function of a unity feedback control system is given as The phase cross over frequency and the gain margin are respectively. |
| A. | and |
| B. | and |
| C. | and |
| D. | and |
| Answer» B. and | |
| 726. |
When phase-lag compensation is used in a system, then gain cross over frequency, bandwidth and undamped frequency are respectively |
| A. | Increased, Increased, Increased |
| B. | Increased, Increased, Decreased |
| C. | Increased, Decreased, Decreased |
| D. | Decreased, Decreased, Decreased |
| Answer» E. | |
| 727. |
Find the voltage across 64 Ω resistor |
| A. | V |
| B. | V |
| C. | V |
| D. | V |
| Answer» D. V | |
| 728. |
Which one of the following is a trivalent material? |
| A. | Antimony |
| B. | Phosphorus |
| C. | Arsenic |
| D. | Boron |
| Answer» E. | |
| 729. |
A noiseless 3 KHz channel can transmit binary at the rate __________ . |
| A. | 12000 bps |
| B. | 10000 bps |
| C. | 6000 bps |
| D. | 3000 bps |
| Answer» D. 3000 bps | |
| 730. |
In a JK flip-flop, J is connected to Q and K is connected to Q outputs. The JK FF converts into a |
| A. | RS FF |
| B. | D FF |
| C. | T FF |
| D. | Clocked RS FF |
| Answer» C. T FF | |
| 731. |
What can be the maximum dimension of an array in C language program? |
| A. | 3 |
| B. | 4 |
| C. | 5 |
| D. | It is compiler dependent |
| Answer» E. | |
| 732. |
Calculate the electrostatic force of repulsion between two mica particles at a distance of 10-13 m from each other. Charge on a particle is 3.2 x 10-19 C. (relative permittivity for mica is 5) |
| A. | 1.843 x 10-15 N |
| B. | 9.2 x 10-2 N |
| C. | 14.41 x 10-9 N |
| D. | none of these |
| Answer» E. | |
| 733. |
The question below consists of a pair of related words followed by four pairs of words. Select the pair that best expresses the relation in the original pair.Unemployed: Worker |
| A. | fallow : land |
| B. | unaware : sleeper |
| C. | wit : jester |
| D. | renovated : house |
| Answer» B. unaware : sleeper | |
| 734. |
At 20 GHz , the gain of a parabolic dish antenna of 1 meter diameter and 70% efficiency is |
| A. | 15 dB |
| B. | 25 dB |
| C. | 35 dB |
| D. | 45 dB |
| Answer» D. 45 dB | |
| 735. |
Find current i. |
| A. | 4/5 A |
| B. | 5/4 A |
| C. | 1.23 A |
| D. | 1.32 A |
| Answer» B. 5/4 A | |
| 736. |
With reference to C programming language, which of the following statements are correct? An identifier may start with an underscore.An identifier may end with an underscore.If is a valid identifier.The number of significant characters in and identifier is implementation dependent. Select the correct answer from the codes given below: |
| A. | 1 and 2 only |
| B. | 2 and 3 only |
| C. | 1, 2, 3 and 4 |
| D. | 3 and 4 only |
| Answer» D. 3 and 4 only | |
| 737. |
The logic function implemented by the following circuit at the terminal OUT is |
| A. | P NOR Q |
| B. | P NAND Q |
| C. | P OR Q |
| D. | P AND Q |
| Answer» E. | |
| 738. |
What is the characteristic of a good control system? |
| A. | Sensitive to parameter variation |
| B. | Insensitive to input command |
| C. | Neither sensitive to parameter variation nor sensitive to input commands |
| D. | Insensitive to parameter variation but sensitive to input commands |
| Answer» E. | |
| 739. |
Separation property of state-transition matrix is |
| A. | φ(t - t0) = φ(t) φ(t0) |
| B. | φ(t - t0) = φ-1(t) φ-1(t0) |
| C. | φ(t - t0) = φ(t) φ-1(t0) |
| D. | φ(t - t0) = φ-1(t) φ-1(t0) |
| Answer» D. œÜ(t - t0) = œÜ-1(t) œÜ-1(t0) | |
| 740. |
The maximum effective aperture of an antenna which is operating at wavelength of 2 m and has a directivity of 100 is __________ . |
| A. | 15.92 |
| B. | 31.84 |
| C. | 3.184 |
| D. | 1.592 |
| Answer» C. 3.184 | |
| 741. |
The characteristic equation of a control system is given as s4 + 8s3 + 24s2 + 32s + K = 0. What is the range of values of K for this system to be stable? |
| A. | 0 ≤ K < 80 |
| B. | 0 ≤ K < 100 |
| C. | 0 ≤ K < 2300 |
| D. | 0 ≤ K < 600 |
| Answer» B. 0 ‚⧠K < 100 | |
| 742. |
In a 4 bit weighted resistor D/A converter, the resistor value corresponding to LSB is 32 kΩ. The resistor value corresponding to MSB will be |
| A. | 32 KΩ |
| B. | 16 KΩ |
| C. | 8 KΩ |
| D. | 4 KΩ |
| Answer» E. | |
| 743. |
(22)4 + (101)3 - (20)5 = (x)4 + (4)x+1 where x > 4. The value of x is |
| A. | 6 |
| B. | 4 |
| C. | 12 |
| D. | 8 |
| Answer» D. 8 | |
| 744. |
Which of the following can be used as a tachogenerator in control systems? |
| A. | Microsyn |
| B. | DC servomotor |
| C. | AC servomotor |
| D. | Magnetic amplifier |
| Answer» D. Magnetic amplifier | |
| 745. |
Consider the CMOS circuit shown, where the gate voltage VG of the n-MOSEFT is increased from zero, while the gate voltage of the p-MOSFET is kept constant at 3 V. Assume that, for both transistor, the magnitude of the threshold voltage is 1 V and the product of the transconductor parameter and the (W/L) ratio, i.e. the quality μC0x(W/L), is 1mA. V-2.For small increase in VG beyond IV, which of the following gives the correct description of the region of operation of each MOSFET? |
| A. | Both the MOSFET are in saturation region |
| B. | Both the MOSFET are in triode region |
| C. | n-MOSFET is in triode and p-MOSFET is in saturation region |
| D. | n-MOSFET is in saturation and p-MOSFET is in triode region |
| Answer» B. Both the MOSFET are in triode region | |
| 746. |
i1(t) for t > 0 is given by |
| A. | 2.5 - 2.5e-2t |
| B. | 2.5 - 1.25e-2t |
| C. | 1.25 - 1.25e-2t |
| D. | None of these |
| Answer» C. 1.25 - 1.25e-2t | |
| 747. |
All the four of the 2 x 2 matrix p = are non zero, and one of its eigen values is zero. Which of the following statements is true? |
| A. | P11P22 - P12P21 = 1 |
| B. | P11P22 - P12P21 = - 1 |
| C. | P11P22 - P12P21 = 0 |
| D. | P11P22 + P12P21 = 1 |
| Answer» D. P11P22 + P12P21 = 1 | |
| 748. |
Find the electric charge required on the earth and moon to balance their gravitational attraction if the charge on the earth is 12.5 times that on the moon.Mass of moon = 6.7 x 1022 KgMass of earth = 6 x 1024 KgDistance between moon and earth = 380 KmUniversal gravitational constant = 6.7 x 10-11 Nm2/Kg2 |
| A. | 48.9 TC |
| B. | 4.89 GC |
| C. | 4.89 TC |
| D. | 48.9 GC |
| Answer» D. 48.9 GC | |
| 749. |
Find the value of ix if each resistance is of 3 Ω and each battery is of 6 V. |
| A. | 1.1428 V |
| B. | 1.432 A |
| C. | 0.2892 A |
| D. | O A |
| Answer» D. O A | |
| 750. |
The figures shows the symbol of |
| A. | p channel depletion MOSFET |
| B. | p channel enhancement MOSFET |
| C. | complementary MOSFET |
| D. | p channel JFET |
| Answer» B. p channel enhancement MOSFET | |