MCQOPTIONS
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MCQOPTIONS
This section includes 38 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. |
In class A operation of an amplifier the current flows through the active device for |
| A. | Whole of the input cycle |
| B. | Half of the input cycle |
| C. | More than half of the input cycle |
| D. | More than three fourth of the input cycle |
| Answer» B. Half of the input cycle | |
| 2. |
A transformer coupled class A amplifier drives a 16 Ohm loud speaker through 4 : 1 transformer with Vcc = 36 V. If the circuit delivers 2 Watts to load, the rms voltage across the load assuming transformer efficiency as 100% is |
| A. | 3.9 V |
| B. | 6.29 V |
| C. | 22.6 V |
| D. | 5.65 V |
| Answer» E. | |
| 3. |
In an amplifier, the output current flows for 200° of input cycle. The class of operation of the amplifier is |
| A. | A |
| B. | AB |
| C. | B |
| D. | C |
| Answer» C. B | |
| 4. |
Class C amplifier operates |
| A. | Entire cycle of i/p signal |
| B. | Half of the cycle of i/p signal |
| C. | Slightly more than half of the cycle of i/p signal |
| D. | Less than half of the cycle of i/p signal |
| Answer» E. | |
| 5. |
High power amplification is achieved by the use of |
| A. | Magnetic amplifier |
| B. | DC amplifier |
| C. | DC generator |
| D. | Amplidyne |
| Answer» C. DC generator | |
| 6. |
In a cell phone, a power amplifier delivering 1 W to the antenna may pull several watts from the battery. If the power conversion efficiency is 30%, then the above cellphone translates to a power drain of: |
| A. | 1 W from the battery |
| B. | 1.3 W from the battery |
| C. | 0.3 W from the battery |
| D. | 3.33 W from the battery |
| Answer» E. | |
| 7. |
In the circuit shown below, the maximum power dissipated by Rs if input varies from 15 V to 20 V (assuming Zener diode used is 10 V, 2W) is? |
| A. | 100 mW |
| B. | 2200 mW |
| C. | 500 mW |
| D. | 600 mW |
| Answer» C. 500 mW | |
| 8. |
For a class-A FET power amplifier with 10 V drain supply and 2 A drain current bias providing RF load current of 1 A amplitude. What is the DC to RF efficiency for load resistance of 5 Ω? |
| A. | 50% |
| B. | 25% |
| C. | 35% |
| D. | 12.5% |
| Answer» E. | |
| 9. |
In class B amplifier, the output current flows for |
| A. | less than half input cycle |
| B. | more than half input cycle |
| C. | half input cycle |
| D. | entire input cycle |
| Answer» D. entire input cycle | |
| 10. |
Consider the following circuits:1. Oscillator2. Emitter follower3. Power amplifierWhich of the above circuits employ feedback? |
| A. | 1 and 2 only |
| B. | 2 and 3 only |
| C. | 1 and 3 only |
| D. | 1, 2 and 3 |
| Answer» E. | |
| 11. |
Astable multivibrator is |
| A. | a square wave clock |
| B. | equivalent to a flip-flop |
| C. | a one shot multivibrator |
| D. | Monostable multivibrator |
| Answer» B. equivalent to a flip-flop | |
| 12. |
In the case of class A amplifiers, the ratio of efficiency of transformer coupled amplifier to the efficiency of a transformerless amplifier is |
| A. | 0.5 |
| B. | 1 |
| C. | 1.36 |
| D. | 2 |
| Answer» E. | |
| 13. |
Identify the common element present inside all voltage regulator ICs from the given options. |
| A. | Load resistor |
| B. | Filter capacitor |
| C. | Transformer |
| D. | Series pass transistor |
| Answer» E. | |
| 14. |
Class C is an amplifier whose output current flows for |
| A. | the entire input cycle |
| B. | less than one-half the entire input cycle |
| C. | twice the entire input cycle |
| D. | greater than one-half the entire input cycle |
| Answer» C. twice the entire input cycle | |
| 15. |
In a class B push-pull amplifier, the transistors are biased slightly above cut-off to avoid |
| A. | crossover distortion |
| B. | unusually high efficiency |
| C. | negative feedback |
| D. | a low input impedance |
| Answer» B. unusually high efficiency | |
| 16. |
Class AB operation is often used in power amplifiers in order to |
| A. | get maximum efficiency |
| B. | remove even harmonics |
| C. | overcome a cross-over distortion |
| D. | reduce collector dissipation |
| Answer» D. reduce collector dissipation | |
| 17. |
In data acquisition _____ block is used for frequency measurement. |
| A. | Analog output |
| B. | Multiplexer |
| C. | Sample & Hold |
| D. | Timer |
| Answer» E. | |
| 18. |
DC to RF efficiency of an ideal class-F amplifier is: |
| A. | 100% |
| B. | 78.4% |
| C. | 50% |
| D. | < 80% |
| Answer» B. 78.4% | |
| 19. |
For an Astable multivibrator shown here, the frequency can be calculated as: |
| A. | \(f=\frac{1.44}{(R_A+R_B)C}\) |
| B. | \(f=\frac{1.44}{(2R_A+R_B)C}\) |
| C. | \(f=\frac{1.44}{(R_A+2R_B)C}\) |
| D. | \(f=\frac{1.44}{(3R_A+2R_B)C}\) |
| Answer» D. \(f=\frac{1.44}{(3R_A+2R_B)C}\) | |
| 20. |
Astable multivibrator operating at 100 Hz has a discharge time 2 ms. Find the duty cycle of the circuit |
| A. | 10% |
| B. | 20% |
| C. | 80% |
| D. | 50% |
| Answer» D. 50% | |
| 21. |
For a class B amplifier providing a 20 V peak signal to 16 ohm load and a power supply of Vcc = 30 V, the efficiency will be. |
| A. | 52.3% |
| B. | 25.65% |
| C. | 75% |
| D. | 78.6% |
| Answer» B. 25.65% | |
| 22. |
For a class B amplifier, using a supply voltage of VCC = 30 V and driving a load of 12 Ω, calculate the transistor dissipation. |
| A. | 12 W |
| B. | 10 W |
| C. | 5 W |
| D. | 8 W |
| Answer» E. | |
| 23. |
Compare the output signal swing of the following power amplifiers(A) Class A(B) Class B(C) Class AB(D) Class CChoose the correct answer from the options given below:(1) (A) > (B) > (C) > (D)(2) (D) > (C) > (B) > (A)(3) (D) > (B) > (C) > (A)(4) (A) > (C) > (B) > (D) |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» E. | |
| 24. |
Crossover distortion does not occur in _______ amplifiers. |
| A. | Push-Pull |
| B. | Class-A |
| C. | Class-B |
| D. | Class-AB |
| Answer» C. Class-B | |
| 25. |
For 555 astable multivibrator, if C = 0.01 μF, R1 = 10 kΩ, R2 = 50 kΩ, the frequency and the duty cycle will be nearly |
| A. | 1.6 kHz and 54.5% |
| B. | 1.3 kHz and 54.5% |
| C. | 1.6 kHz and 46.5% |
| D. | 1.3 kHz and 46.5% |
| Answer» C. 1.6 kHz and 46.5% | |
| 26. |
In Class – A amplifier, the output current flows for |
| A. | a part of the cycle of the input signal |
| B. | the full cycle of the input signal |
| C. | half the cycle of the input signal |
| D. | ¾ of the cycle of the input signal |
| Answer» C. half the cycle of the input signal | |
| 27. |
In the case of an ideal Class-F microwave power amplifier, time-domain voltage and current waveform of the device have: |
| A. | 50% overlap |
| B. | Maximum overlap |
| C. | No overlap |
| D. | Less than 80% overlap |
| Answer» D. Less than 80% overlap | |
| 28. |
In a class A amplifier with a sinusoidal input signal, the output current flows for: |
| A. | half the cycle |
| B. | full cycle |
| C. | less than half cycle |
| D. | more than half cycle |
| Answer» C. less than half cycle | |
| 29. |
In class AB amplifiers, the current flows through the active device for |
| A. | Full duration of input cycle |
| B. | half duration of input cycle |
| C. | more than half but less than full cycle duration |
| D. | less than half of the duration of input cycle |
| Answer» D. less than half of the duration of input cycle | |
| 30. |
In a class C power amplifier, the input frequency of ac signal is 1 MHz. If tank circuit has C = 1000 pF, the value of L approximately is |
| A. | 200 μH |
| B. | 10 μH |
| C. | 100 μH |
| D. | 25 μH |
| Answer» E. | |
| 31. |
Harmonic distortion in amplifiers is caused by |
| A. | presence of shot noise |
| B. | deflective active device |
| C. | non-linearity of active device |
| D. | positive feedback from output to input |
| Answer» D. positive feedback from output to input | |
| 32. |
In case of amplifiers, which coupling gives the highest gain? |
| A. | Transformer coupling |
| B. | Resistance coupling |
| C. | Impedance coupling |
| D. | Capacitance coupling |
| Answer» B. Resistance coupling | |
| 33. |
An output signal of a power amplifier has amplitudes of 2.5 V fundamental, 0.25 V second harmonic and 0.1 V third harmonic. The total percentage harmonic distortion of the signal is |
| A. | 12.8% |
| B. | 10.8% |
| C. | 6.4% |
| D. | 1.4% |
| Answer» C. 6.4% | |
| 34. |
By combining two Class B amplifiers, we can build ____ |
| A. | Push-pull amplifier |
| B. | LC coupling |
| C. | RC coupling |
| D. | TC coupling |
| Answer» B. LC coupling | |
| 35. |
A two transistor class B amplifier is commonly called |
| A. | dual amplifier |
| B. | symmetrical amplifier |
| C. | differential amplifier |
| D. | push pull amplifier |
| Answer» E. | |
| 36. |
If three amplifiers having the same bandwidth are cascaded, the bandwidth of the resulting amplifier will be |
| A. | Better than that of each stage |
| B. | Worse than that of each stage |
| C. | Same as that of each stage |
| D. | None of the above |
| Answer» C. Same as that of each stage | |
| 37. |
A square wave signal was applied to an amplifier with a poor low-frequency response. The output waveform had |
| A. | distorted flat-top portion |
| B. | distorted vertical edges |
| C. | not suffer any distortion |
| D. | been converted into a triangular waveform |
| Answer» B. distorted vertical edges | |
| 38. |
Match the following list:List - IList - II(a) Maximum efficiency of a Class B amplifier(i) 100%(b) Maximum efficiency of a Class A amplifier(ii) 78.5%(c) Maximum efficiency of a Class C amplifier(iii) 50%(d) Rectification efficiency of half-wave rectifier when rd |
| A. | (a) – (i), (b) – (ii), (c) – (iii), (d) – (iv) |
| B. | (a) – (ii), (b) – (iii), (c) – (i), (d) – (iv) |
| C. | (a) – (ii), (b) – (iv), (c) – (iii), (d) – (i) |
| D. | (a) – (iv), (b) – (i), (c) – (iii), (d) – (ii) |
| Answer» C. (a) – (ii), (b) – (iv), (c) – (iii), (d) – (i) | |