NTA UGC NET/JRF Exam, February-2023 (Electronic Science)

Total Questions: 100

41. Read the statements:

(a) The O/P frequency of a half wave rectifier is equal to the input frequency
(b) The O/P frequency of a full wave rectifier is double to the input frequency
(c) The regulation of an excellent rectifier should be zero.
(d) Ripple factor in the full wave rectifier is 1.2.
Choose the correct statements from the options given below:

Correct Answer: D. (a), (c) only

42. Read the statements regarding transistor.

(a) The dopping level of emitter region is more than base region but less than collector region.
(b) The CB configuration is a good current amplifier circuit configuration
(c) The phase difference between I/P and O/P waveforms of a CB configuration amplifying circuit is 0°.
(d) CC configuration transistor amplifier has higher value of I/P resistance and lower values of O/P resistance.
Choose the correct answer from the options given below:

Correct Answer: A. (c) & (d) onl
Solution:

(a) In a transistor, the emitter is the most heavily doped, followed by the collector, and then the base. This ensures efficient operation and minimizes the base width modulation.
(b) Common Base (CB) configuration isn't usually used as an amplifier. It's the Common Emitter (CE) configuration that's a good current amplifier.
(c) In CB configuration, the output and input signals are in phase.
(d) Common Collector (CC) configuration, often known as an emitter follower, has high input impedance and low output impedance.

43. In MOS


Choose the correct answer from the options given below:

Correct Answer: C. (a) & (c) only
Solution:

44. In VLSI Design flow,

(a) Algorithm describes the behaviour of target chip.
(b) Architecture of processor is not mapped onto the chip surface by floor planning.
(c) Behavioral domain defines FSMs.
(d) Individual modules are implemented with leaf cells.
Choose the correct answer from the options given below:

Correct Answer: A. (a), (c) & (d) only
Solution:(a) The behavior of the is target chip described algorithmically to begin the design process. This provides a highlevel representation of what the chip should accomplish.
(b) Floor planning in VLSI involves mapping the architecture of the processor onto the chip surface, determining where modules will be placed, and planning interconnect routes.
(c) The behavioral domain defines the functional aspects of the chip, including Finite State Machines (FSMs) which dictate how the chip will respond to various inputs.
(d) Individual modules are indeed implemented using leaf cells, which are the building blocks in a standard cell library.

45. The RLC circuit given in figure below can be solved

(a) Current i(t) can be solved using KVL
(b) Current i(t) can be solved using KCL
(c) Current i(t) can be solved using Fourier transform
(d) Current i(t) can be solved using Laplace transform
(e) Current i(t) can be solved using Fourier series
Choose the correct answer from the options given below:

Correct Answer: C. (a) & (d) only
Solution:

(a) For an RLC circuit, Kirchhoff's Voltage Law (KVL) can be applied to determine the relationship between voltages in the circuit. Using this, one can derive an equatión for current i(t).
(b) Kirchhoff's Current Law (KCL) relates the currents entering and leaving a node. While it's valuable in many contexts, for an RLC circuit in series, KVL is more directly applicable.
(c) The Fourier Transform allows conversion from the time domain to the frequency domain, and it can be used to solve circuits with sinusoidal sources.
(d) The Laplace Transform is a powerful tool for solving linear differential equations, like those derived from RLC circuits.
(e) The Fourier series is used to represent periodic functions as a sum of sines and cosines, and while it's useful in analyzing periodic signals, it might not be the primary method for solving the current in an RLC circuit.

46. Power absorbed by an element for t = 10 sec. if the current magnitude is

Correct Answer: A. (a) & (b) only

47. In an operational amplifiers:


Choose the correct answer from the options given below:

Correct Answer: B. (b) & (d) only
Solution:

48. Statements regarding rectifier are :

(a) RMS value of current in a half wave rectifier is Im/√2
(b) PIV of diode in a full wave bridge rectifier is Vm volts.
(c) TUF and rectification efficiency for a rectifier are same parametrs.
(d) Rectifier converts AC to rippled DC not pure DC.
Choose the correct answer from the options given below:

Correct Answer: C. (b) & (d) only
Solution:(a) The RMS value of current for a halfwave rectifier is lower than that of a fullwave rectifier. The exact value would depend on the input waveform.
(b) In a full-wave bridge rectifier, the Peak Inverse Voltage (PIV) of a diode is equal to the peak voltage, Vₘ
(c) TUF (Transformer Utilization Factor) and rectification efficiency are two different parameters. While both are measures of performance, they evaluate different aspects.
(d) Rectifiers convert AC to rippled DC, and further filtering is required to get a smooth DC output.

49. Statements in connection to Op-Amp applications are:

(a) If we use a square wave generator followed by integrator circuit we get a triangular wave at the output
(b) The logarithmic amplifier called a logamplifier or a logger, is basically a current to voltage converter.is a first order high pass filter with voltage follower
(d) If we use a square wave generator followed by a clipping circuit then we get a saw-tooth wave generator.
Choose the correct answer from the options given below:

Correct Answer: A. (a) & (b) only

50. The logic families have fan out more than TTL:

(a) RTL                     (b) ECL
(c) DTL                     (d) CMOS
Choose the correct answer from the options given below.

Correct Answer: B. (b) and (d) only
Solution:(a) RTL (Resistor-Transistor Logic) is an older technology and has a relatively low fan-out.
(b) ECL (Emitter-Coupled Logic) is known for its high speed and has a greater fanout compared to TTL (TransistorTransistor Logic).
(c) DTL (Diode-Transistor Logic) was a predecessor to TTL and typically has a fan-out comparable to or less than TTL.
(d) CMOS (Complementary Metal-OxideSemiconductor) logic circuits are characterized by low power consumption and have a fan-out greater than TTL. This is because CMOS devices consume power mainly during the switching and not when static.