MCQOPTIONS
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MCQOPTIONS
This section includes 23 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.
| 1. |
Pulsating output of a rectifier is converted into a steady DC level by |
| A. | Amplifier |
| B. | Modulator |
| C. | Filter Circuit |
| D. | Transistor |
| Answer» D. Transistor | |
| 2. |
In any function where microphone, amplifier and speakers are used often one would hear a humming sound, which increases in volume gradually. This is due to: |
| A. | Positive feedback between microphone and speaker |
| B. | Negative feedback between microphone and speaker |
| C. | Inadequate frequency response of amplifier |
| D. | Noise pickup (50 Hz) from power supply |
| Answer» B. Negative feedback between microphone and speaker | |
| 3. |
Power dissipation and efficiency of series type switching regulator should follow which trend respectively? |
| A. | Increasing, increasing |
| B. | Increasing, reducing |
| C. | Decreasing, decreasing |
| D. | Reducing, increasing |
| Answer» E. | |
| 4. |
Identify the main feature of power amplifiers from the options given below. |
| A. | They have voltage amplifiers in the preceding stage. |
| B. | They cannot be operated without transformers. |
| C. | Their output voltage is high. |
| D. | Their output impedance is high. |
| Answer» C. Their output voltage is high. | |
| 5. |
For an N bit F – V converter, to ensure less than ½ LSB output ripple, the time constant T of simple RC low pass filter must be at least (Where T0 is the output period of the n bit converter): |
| A. | T = 0.69 (n + 1)T0 |
| B. | T = (n + 1)T0 |
| C. | T = 0.69 n T0 |
| D. | T = n T0 |
| Answer» B. T = (n + 1)T0 | |
| 6. |
Most commonly used control element in voltage regulators is |
| A. | BJT |
| B. | UJT |
| C. | FET |
| D. | SBS |
| Answer» B. UJT | |
| 7. |
Main element of a filter circuit that reduces the A.C. component of the output is |
| A. | resistor |
| B. | inductor |
| C. | transformer |
| D. | capacitor |
| Answer» E. | |
| 8. |
Directions: It consists of two statements, one labelled as the ‘Statement (I)’ and the other as ‘Statement (II)’. You are to examine these two statements carefully and select the answer using the codes given below:Statement (I): In push-pull operation one transistor conducts only for negative half cycle and other for positive half cycle.Statement (II): Class-B power amplifier is fixed in cut-off, which gives non-distorted output. |
| A. | Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I) |
| B. | Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I) |
| C. | Statement (I) is true but Statement (II) is false |
| D. | Statement (I) is false but Statement (II) is true |
| Answer» D. Statement (I) is false but Statement (II) is true | |
| 9. |
Low efficiency of a power amplifier results in |
| A. | Low forward bias |
| B. | Less battery consumption |
| C. | More battery consumption |
| D. | none of these |
| Answer» D. none of these | |
| 10. |
If a high degree of selectivity is desired, then double tuned circuit should have |
| A. | Loose coupling |
| B. | Tight coupling |
| C. | Critical coupling |
| D. | none of these |
| Answer» B. Tight coupling | |
| 11. |
Attenuators are used |
| A. | to increase the signal level |
| B. | to reduce the signal level |
| C. | to maintain the signal level constant |
| D. | None of these |
| Answer» C. to maintain the signal level constant | |
| 12. |
A positive half wave rectifier is a: |
| A. | Positive Clipper |
| B. | Negative Clipper |
| C. | Negative Clamper |
| D. | Positive Clamper |
| Answer» C. Negative Clamper | |
| 13. |
A high Q tuned circuit in a tuned amplifier permits it to have which of the following? |
| A. | High selectivity |
| B. | High frequency range |
| C. | High sensitivity |
| D. | High fidelity |
| Answer» B. High frequency range | |
| 14. |
If R1 = 10k, R2 = 10k and capacitance = 10 μF the total time period of the astable multivibrator 555 is: |
| A. | 0.207 s |
| B. | 0.5 s |
| C. | 0.138 s |
| D. | 0.069 s |
| Answer» B. 0.5 s | |
| 15. |
Power amplifiers generally use transformer coupling because transformer permit |
| A. | cooling of the circuit |
| B. | Impedance matching |
| C. | distortion-less output |
| D. | good frequency response |
| Answer» C. distortion-less output | |
| 16. |
A full wave rectifier produces an rms voltage of 10 V from 50 Hz line and feeds a resistive load of 1100 Ω. If the filter uses a capacitance of C = 50 μF, calculate the output ripple factor. |
| A. | 18.86 |
| B. | 0.053 |
| C. | 0.21 |
| D. | 0.09 |
| Answer» C. 0.21 | |
| 17. |
In a single tuned capacitance coupled amplifier, the frequency response depends on |
| A. | only the input circuit |
| B. | only the output circuit |
| C. | both input and output circuits |
| D. | neither input circuit nor the output circuit |
| Answer» C. both input and output circuits | |
| 18. |
Match the following list:List - IList – IIa) In half wave Rectifier dc voltage across load approximately for (rd ≪ RL)i) \(\frac{{{V_m}}}{\pi }\)b) Rectification efficiency of full wave rectifier in % isii) \(\beta = \frac{1}{{29}}\)c) Gain of amplifier in dBiii) \(\frac{{81.2}}{{1 + \frac{{{r_d}}}{{{R_L}}}}}\)d) Feedback factor when RC network is phase shift oscillator gives exactly 180° phase shiftiv) \(20{\log _{10}}\frac{{{V_2}}}{{{V_1}}}\) Correct code are: |
| A. | (a) – (ii), (b) – (i), (c) – (iii), (d) – (iv) |
| B. | (a) – (i), (b) – (iii), (c) – (iv), (d) – (ii) |
| C. | (a) – (iii), (b) – (ii), (c) – (iv), (d) – (i) |
| D. | (a) – (iv), (b) – (iii), (c) – (ii), (d) – (i) |
| Answer» C. (a) – (iii), (b) – (ii), (c) – (iv), (d) – (i) | |
| 19. |
For the op-Amp series regulator given below the output regulated voltage is_____ |
| A. | 26.2 V |
| B. | 24.8 V |
| C. | 20.6 V |
| D. | 6.2 V |
| Answer» C. 20.6 V | |
| 20. |
An amplifier circuit has an overall current gain of -100 and an input resistance of 10 kΩ with a load resistance of 1 kΩ. The overall voltage gain of the amplifier is |
| A. | 5 dB |
| B. | 10 dB |
| C. | 20 dB |
| D. | 40 dB |
| Answer» D. 40 dB | |
| 21. |
In an amplifier the maximum power transfer to the load resistance should be |
| A. | As small as possible |
| B. | As large as possible |
| C. | Equal to the value of the input resistance of the amplifier |
| D. | Equal to the value of the output impedance |
| Answer» E. | |
| 22. |
In VCO IC 566, the value of charging & discharging is dependent on the voltage applied at ________. |
| A. | Triangular wave output |
| B. | Square wave output |
| C. | Modulating input |
| D. | Sawtooth input |
| Answer» D. Sawtooth input | |
| 23. |
An amplifier has a signal input voltage Vi of 0.25 V draws 1 mA from the source. If the amplifier delivers 8 V to a load of 10 mA, the power gain is |
| A. | 340 |
| B. | 320 |
| C. | 250 |
| D. | 150 |
| Answer» C. 250 | |