MCQOPTIONS
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MCQOPTIONS
This section includes 55 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 the AC equivalent circuit shown in Fig, if Iin is the Input current and Feedback Resistance is very large, the type of Feedback |
| A. | Voltage – Voltage Feedback Iin |
| B. | Voltage – Current Feedback |
| C. | Current – Current Feedback |
| D. | Current – Voltage Feedback |
| Answer» C. Current – Current Feedback | |
| 2. |
_______ is used for keeping oscillator frequency away from any drift |
| A. | PLL |
| B. | VCO |
| C. | Comparator |
| D. | Frequency synthesizer |
| Answer» B. VCO | |
| 3. |
During a low frequency response of an amplifier which is invariably of RC-coupled type, there is a range of frequency characteristics over which the amplification is constant and delay is also constant, called |
| A. | Low band frequency |
| B. | Mid band frequency |
| C. | High band frequency |
| D. | Hyper band frequency |
| Answer» C. High band frequency | |
| 4. |
A signal containing frequency component from 445 kHz to 465 kHz is to be amplified. Which of the following will be suitable for the purpose? |
| A. | Direct coupled amplifier |
| B. | RC coupled amplifier |
| C. | RC coupled amplifier using triodes |
| D. | Transformer coupled tuned amplifier using transistors |
| Answer» E. | |
| 5. |
A square wave generator is also called:(1) one-shot multivibrator(2) sample and hold circuit(3) free - running multivibrator(4) voltage-to-current convertor |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 6. |
Direction: Given question consists of two statements, one labeled as the 'Assertion (A)' and the other as 'Reason (R)'.You are to examine these two statements carefully and select the answers to these items using the codes given below.Assertion (A): The frequency stability of an oscillator improves as \(\frac {dθ}{d\omega}\) increases, where θ refers to the phase angle of the loop gain.Reason (R): For sustained oscillation to occur in an oscillator circuit, the loop shift should be 0° or 2n π where n is an integer. |
| A. | Both A and R are individually true and R is the correct explanation of A |
| B. | Both A and R are individually true but R is NOT the correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» E. | |
| 7. |
In Hartley oscillator generating 2 MHz if C = 0.001 nano farads the value of L = _____. |
| A. | 12.66 milli Henry |
| B. | 6.33 milli Henry |
| C. | 25.33 milli Henry |
| D. | 63.33 milli Henry |
| Answer» C. 25.33 milli Henry | |
| 8. |
Barkhausen criterion for oscillations is |
| A. | |Aβ| = 1 |
| B. | Aβ = 0 |
| C. | – Aβ = 1 |
| D. | A = 1/√β |
| Answer» B. Aβ = 0 | |
| 9. |
Hartley oscillator is |
| A. | An inductively coupled oscillator |
| B. | Capacitor coupled oscillator |
| C. | Switchable for low frequencies |
| D. | Resist mace coupled oscillator |
| Answer» B. Capacitor coupled oscillator | |
| 10. |
In an amplifier with the negative feedback, bandwidth is _________ and voltage gain is _________. |
| A. | Bandwidth is decreased by a factor (1+Aβ) and voltage gain decreases |
| B. | Bandwidth is decreased by factor β and voltage gain remains same |
| C. | Bandwidth is increased by the factor (1+Aβ) and voltage gain is reduced |
| D. | Bandwidth remains the same and voltage gain increases |
| Answer» D. Bandwidth remains the same and voltage gain increases | |
| 11. |
Consider the following piezoelectric materials.(a) Quartz(b) Tourmaline(c) Lithium sulphateArrange the above piezoelectric materials in decreasing order of their useful temperature ranges: |
| A. | (a), (b), (c) |
| B. | (a), (c), (b) |
| C. | (b), (a), (c) |
| D. | (b), (c), (a) |
| Answer» D. (b), (c), (a) | |
| 12. |
DC bias is adjusted greater than its cut-off value so that the output current flow for less than half of the input voltage cycle, in: |
| A. | Class A amplifier |
| B. | Class B amplifier |
| C. | Class C amplifier |
| D. | Class AB amplifier |
| Answer» D. Class AB amplifier | |
| 13. |
Assertion: The process of testing the frequency response of amplifier and filter can be done by sweep frequency generator that automatically varies its frequency over a pre-determined range.Reason: The sweep frequency generator should have a ramp generator which applies a linear ramp voltage the input of a voltage tuned oscillator (VTO). |
| A. | Both A and R is true and R is the correct explanation of A |
| B. | Both A and R is true and R is not the correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» B. Both A and R is true and R is not the correct explanation of A | |
| 14. |
In an LC oscillator, the frequency of oscillator is________ L or C. |
| A. | Proportional to square of |
| B. | Directly proportional to |
| C. | Independent of the values of |
| D. | Inversely proportional to square root of |
| Answer» E. | |
| 15. |
Among the following, identify the incorrect statement. |
| A. | An oscillator is a circuit that convers DC to AC. |
| B. | All oscillators generate sine wave. |
| C. | An oscillator is an amplifier that supplies its own input signal. |
| D. | In-phase feedback is called positive feedback. |
| Answer» C. An oscillator is an amplifier that supplies its own input signal. | |
| 16. |
Consider the following statements about Schmitt trigger(a) The output of a Schmitt Trigger is a square wave when input is a sine wave(b) Schmitt Trigger can be used in Triangular wave and sawtooth wave generators(c) The comparator with negative feedback is said to exhibit hysteresis, a dead band condition(d) The output is impulse waveform when the input to Schmitt Trigger is a sawtooth waveWhich of the above statements are correct? |
| A. | (a) and (b) |
| B. | (b) and (c) |
| C. | (c) and (d) |
| D. | (b) and (d) |
| Answer» B. (b) and (c) | |
| 17. |
In an OPAMP Wien Bridge Oscillator, two pairs of R and C are used when the frequency of oscillation is 200 kHz. If the value of C is 10 pF, find the value of R. |
| A. | 59.98 kΩ |
| B. | 79.58 kΩ |
| C. | 88.67 kΩ |
| D. | 68.87 kΩ |
| Answer» C. 88.67 kΩ | |
| 18. |
Find the value of the resistance required for a Wien bridge oscillator to operate at 1 kHz with a capacitance of 1 μF. |
| A. | 500/π |
| B. | 1000/π |
| C. | \(\frac{{500}}{{\sqrt 6 \pi }}\) |
| D. | 1000 π |
| Answer» B. 1000/π | |
| 19. |
Crystal oscillator uses |
| A. | silicon crystal |
| B. | germanium crystal |
| C. | crystal diode |
| D. | piezo-electric quartz crystal |
| Answer» E. | |
| 20. |
A signal Vmsin (ωt + φ) is applied to an amplifier whose gain A is independent of frequency. The amplifier will preserve the form of the input signal (though with a delay) if the phase shift φ is: |
| A. | Constant |
| B. | Inversely proportional to frequency |
| C. | Proportional to frequency |
| D. | Proportional to the square of the frequency |
| Answer» B. Inversely proportional to frequency | |
| 21. |
Consider the oscillator circuit shown in the figure. The function of the network (shown in dotted lines) consisting of the 100 kΩ resistor in series with the two diodes connected back-to-back is to: |
| A. | introduce amplitude stabilization by preventing the op amp from saturating and thus producing sinusoidal oscillations of fixed amplitude |
| B. | introduce amplitude stabilization by forcing the opamp to swing between positive and negative saturation and thus producing square wave oscillations of fixed amplitude |
| C. | introduce frequency stabilization by forcing the circuit to oscillate at a single frequency |
| D. | enable the loop gain to take on a value that produces square wave oscillations |
| Answer» B. introduce amplitude stabilization by forcing the opamp to swing between positive and negative saturation and thus producing square wave oscillations of fixed amplitude | |
| 22. |
A Wein bridge oscillator produces 4 kHz. For identical networks if C = 0.01 microfarads then R = _______. |
| A. | 8 kΩ |
| B. | 4 kΩ |
| C. | 12.5 kΩ |
| D. | 1.58 kΩ |
| Answer» C. 12.5 kΩ | |
| 23. |
A Wien Bridge Oscillator is suitable for1. Audio frequency applications2. Radio frequency applications3. Very low frequency applicationsWhich of the above frequency applications is/are correct? |
| A. | 1 only |
| B. | 2 only |
| C. | 3 only |
| D. | 1, 2 and 3 |
| Answer» B. 2 only | |
| 24. |
In a voltage series feedback amplifier with load RL, if Ri is the input resistance without feedback, then the input resistance with feedback is:a) Ri (1 + βAv)b) Ri (1 - βAv)c) \(\frac{{{R_i}}}{{1 + \beta {A_v}}}\)d) \(\frac{{{R_i}\beta {A_v}}}{{{R_L}}}\)of these statements: |
| A. | (a) and (c) are correct |
| B. | (b) and (d) are wrong |
| C. | (a) and (d) are wrong |
| D. | (c) and (a) are wrong |
| Answer» C. (a) and (d) are wrong | |
| 25. |
An op-amp circuit that has its output tied directly to the inverting input signal is called |
| A. | Current follower |
| B. | Voltage follower |
| C. | Inverting amplifier |
| D. | Integrator |
| Answer» C. Inverting amplifier | |
| 26. |
A feedback amplifier is designed with an amplifier gain of – 1000 and feedback of β = 0.1 If the amplifier had a gain change of 20% due to temperature, the change in gain of the feedback amplifier is: |
| A. | 1% |
| B. | 5% |
| C. | 0.2% |
| D. | 0.01% |
| Answer» D. 0.01% | |
| 27. |
Colpitt's Oscillator works in ________ mode. |
| A. | Class A |
| B. | Class B |
| C. | Class C |
| D. | Class AB |
| Answer» D. Class AB | |
| 28. |
In an oscillator circuit, 5% of the output is fed back positively to the input. What is the minimum gain required for oscillations to occur? (Assume that proper phase-shift is achieved) |
| A. | 50 |
| B. | 0.95 |
| C. | 20 |
| D. | 1.05 |
| Answer» D. 1.05 | |
| 29. |
Oscillators are widely used in |
| A. | radio broadcasting |
| B. | television broadcasting |
| C. | radio and television receiver |
| D. | All of these |
| Answer» E. | |
| 30. |
In a sinusoidal oscillator, sustained oscillations will be produced only if the loop gain (at the oscillation frequency) is |
| A. | Less than unity but not zero |
| B. | Zero |
| C. | Unity |
| D. | Greater than unity |
| Answer» D. Greater than unity | |
| 31. |
In a crystal oscillator, especially when piezoelectric crystal like quartz is applied, then the inductor L, capacitor C, and resistor R are the analogous of the mechanical system as |
| A. | Mass, compliance, viscous-damping factor |
| B. | Mass, spring constant, viscous-damping factor |
| C. | Mass, momentum, viscous-damping factor |
| D. | Mass, displacement, viscous-damping factor |
| Answer» B. Mass, spring constant, viscous-damping factor | |
| 32. |
In a voltage-series-feedback amplifier with open loop gain Av and the feedback factor β, the input resistance becomes |
| A. | \(\frac{{{R_i}}}{{\left( {1 + \beta {A_v}} \right)}}\) |
| B. | \({R_i}\sqrt {\left( {1 + \beta {A_v}} \right)} \) |
| C. | Ri (1 + βAv) |
| D. | \(\frac{{{R_i}}}{{\sqrt {\left( {1 + \beta {A_v}} \right)} }}\) |
| Answer» D. \(\frac{{{R_i}}}{{\sqrt {\left( {1 + \beta {A_v}} \right)} }}\) | |
| 33. |
In the phase-shift oscillator, the operating frequency is determined by |
| A. | Resistance only |
| B. | Capacitance only |
| C. | LC combinations |
| D. | RC combinations |
| Answer» E. | |
| 34. |
In a phase shift oscillator using an FET, at a certain frequency if the phase shift introduced by the RC network is 180°, then the total phase shift from gate around the circuit and back to the gate will be |
| A. | 0° |
| B. | 90° |
| C. | 180° |
| D. | 270° |
| Answer» B. 90° | |
| 35. |
In the Wein Bridge oscillator circuit shown in figure, the bridge is balanced when |
| A. | \(\frac{{{R_3}}}{{{R_4}}} = \frac{{{R_1}}}{{{R_2}}},\omega = \frac{1}{{\sqrt {{R_1}{C_1}{R_2}{C_2}} }}\) |
| B. | \(\frac{{{R_2}}}{{{R_1}}} = \frac{{{C_2}}}{{{C_1}}},\omega = \frac{1}{{{R_1}{C_1}{R_2}{C_2}}}\) |
| C. | \(\frac{{{R_3}}}{{{R_4}}} = \frac{{{R_1}}}{{{R_2}}} + \frac{{{C_2}}}{{{C_1}}},\omega = \frac{1}{{\sqrt {{R_1}{C_1}{R_2}{C_2}} }}\) |
| D. | \(\frac{{{R_3}}}{{{R_4}}} + \frac{{{R_1}}}{{{R_2}}} = \frac{{{C_2}}}{{{C_1}}},\omega = \frac{1}{{{R_1}{C_1}{R_2}{C_2}}}\) |
| Answer» D. \(\frac{{{R_3}}}{{{R_4}}} + \frac{{{R_1}}}{{{R_2}}} = \frac{{{C_2}}}{{{C_1}}},\omega = \frac{1}{{{R_1}{C_1}{R_2}{C_2}}}\) | |
| 36. |
Given 3 KHz is generated by Phase Shift oscillator with C = 0.1 microfarads; the value of R = _____ networks. |
| A. | 220 ohms |
| B. | 530 ohms |
| C. | 440 ohms |
| D. | 940 ohms |
| Answer» B. 530 ohms | |
| 37. |
Another name for a unity gain amplifier is |
| A. | Difference amplifier |
| B. | Comparator |
| C. | Single ended |
| D. | Voltage follower |
| Answer» E. | |
| 38. |
Large Signal Amplifier is also known as |
| A. | Voltage Amplifier |
| B. | Power Amplifier |
| C. | Current Amplifier |
| D. | Circuit Amplifier |
| Answer» C. Current Amplifier | |
| 39. |
A good transconductance amplifier should have |
| A. | high input resistance and low output resistance |
| B. | low input resistance and high output resistance |
| C. | high input and output resistance |
| D. | low input and output resistance |
| Answer» D. low input and output resistance | |
| 40. |
In a negative feedback amplifier, current sampling |
| A. | tends to decrease the output resistance |
| B. | tends to increase the output resistance |
| C. | does not alter the output resistance |
| D. | produces the same effect on output resistance as voltage sampling |
| Answer» C. does not alter the output resistance | |
| 41. |
One of the following oscillator types provides an extremely stable output frequency |
| A. | Hartley Oscillator |
| B. | Wein bridge oscillator |
| C. | Crystal oscillator |
| D. | Clap oscillator |
| Answer» D. Clap oscillator | |
| 42. |
Match the following:List IList II(a) Voltage series(i) Voltage amplifier(b) Voltage shunt(ii) Current amplifier(c) Current series(iii) Transconductance amplifier(d) Current shunt(iv) Trans resistance amplifier |
| A. | (a) – (ii), (b) – (i), (c) – (iv), (d) – (iii) |
| B. | (a) – (i), (b) – (iv), (c) – (iii), (d) – (ii) |
| C. | (a) – (ii), (b) – (iii), (c) – (i), (d) – (iv) |
| D. | (a) – (iv), (b) – (i), (c) – (ii), (d) – (iii) |
| Answer» C. (a) – (ii), (b) – (iii), (c) – (i), (d) – (iv) | |
| 43. |
In a feedback amplifier, which configuration increases bandwidth, decreases non-linear distortion and improves transconductance with negative feedback? |
| A. | Voltage-series |
| B. | Current-series |
| C. | Voltage-shunt |
| D. | Current-shunt |
| Answer» C. Voltage-shunt | |
| 44. |
In a negative feedback amplifier, the output impedance is decreased |
| A. | If the signal sampled is a voltage |
| B. | If the signal sampled is a current |
| C. | If the feedback signal is a voltage |
| D. | If the feedback signal is a current |
| Answer» B. If the signal sampled is a current | |
| 45. |
A current controlled current source (CCCS) has an input impedance of 10 Ω and output impedance of 100 kΩ. When this CCCS is used in a negative feedback closed loop with a loop gain of 9, the closed loop output impedance is |
| A. | 10 Ω |
| B. | 100 Ω |
| C. | 100 kΩ |
| D. | 1000 kΩ |
| Answer» E. | |
| 46. |
A frequency tuning electronic circuit would consist of |
| A. | an inductor and a capacitor |
| B. | an inductor and a resistor |
| C. | two inductors |
| D. | two capacitors |
| Answer» C. two inductors | |
| 47. |
Assertion (A): A UJT (Unijunction Transistor) finds application in making a relaxation oscillator of a certain given frequency.Reason (R): It has three terminals like that of a transistor - corresponding to emitter-base and collector. Therefore it can be used to make an oscillator as well as an amplifier. |
| A. | Both (A) and (R) are true and (R) is the correct explanation of (A) |
| B. | Both (A) and (R) are true, but (R) is not the correct explanation of (A) |
| C. | (A) is true, but (R) is false |
| D. | (A) is false, but (R) is true |
| Answer» D. (A) is false, but (R) is true | |
| 48. |
An electronic oscillator is: |
| A. | just like an alternator |
| B. | nothing but an amplifier |
| C. | an amplifier with feedback |
| D. | a converter of a.c. to d.c. energy |
| Answer» D. a converter of a.c. to d.c. energy | |
| 49. |
For the negative feedback amplifier shown in the given figure, the gain with feedback is 100. What is the gain without feedback? |
| A. | 10 |
| B. | 0.1 |
| C. | 100 |
| D. | 1000 |
| Answer» E. | |
| 50. |
Astable multivibrator may be used as |
| A. | Frequency to voltage converter |
| B. | Voltage to frequency converter |
| C. | Squaring circuit |
| D. | Comparator circuit |
| Answer» C. Squaring circuit | |