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

Total Questions: 100

11. Two port network is given in Figure above, select equations for transmission parameters from the given below equations:

Correct Answer: C.

12. For fourier series of wave shown in Figure below, Select correct expression for f(t)

Correct Answer: A.

13. The quienscent state of transistor is when:

Correct Answer: B. Biased but no signal is applied
Solution:

The quiescent state of a transistor refers to its steady-state operation when it's biased appropriately but no signal (neither AC nor varying DC) is applied to it. In this state, the transistor's operating point (also called the Q-point) is set. This Q-point determines the DC collector current and collector-to-emitter voltage when no signal is present. The right biasing ensures the transistor operates in its active region, ready to amplify any applied signal.

14. The current amplification factor in radian square of Colpitts oscillator is:

Correct Answer: A.

15. The two input terminals of an op-amp are connected to voltage signals of strength 745 µV and 740 µV respectively. The gain of the Op-Amp in differential mode is 5 x 10⁵ and CMRR is 100 dB. What should be the output voltage?

Correct Answer: D. 2.57 V
Solution:Given the op-amp setup, the differential input voltage is:

16. The given operational amplifier circuit corresponds to which electronic circuit application?

Correct Answer: A. Half wave rectification
Solution:

Operational amplifiers (op-amps) can be employed in many circuit configurations. When an op-amp is utilized in rectification, it's generally for precision rectification which eliminates diode voltage drops. Given the precision half-wave rectification. A half-wave rectifier allows only one half of an AC wave to pass through to the load. If the op-amp was used in a full-wave configuration, it would precisely rectify both halves of the waveform.

17. Choose the correct answer from the decimal to octal conversion given below.

Correct Answer: A. (0.125)₁₀ = (0.100)₈
Solution:This means the fraction 0.125 in decimal is equivalent to 0.1 in octal, making option A the correct choice.

18. Compute output of following logic gates as combinational circuit.

Correct Answer: B.

19. Sum of products equation is given below as


Correct Answer: B.

20. The truth table of D flip-flop is given below:

Choose exact characteristic equation based on above Truth Table.

Correct Answer: B.
Solution:

The D flip-flop, also known as a data.or delay flip-flop, has an output Q that takes the state of the input D at the moment of a positive edge at the clock input. So, the characteristic equation of a D flip-flop is simply Qn+1 = D.

From the options given, the one that most closely matches this expression is B. The other options don't capture the fundamental behaviour of the D flip-flop. This flip-flop is primarily used for storage or data transfer applications in digital circuits.