MCQOPTIONS
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MCQOPTIONS
This section includes 657 Mcqs, each offering curated multiple-choice questions to sharpen your Testing Subject knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The signal input to a given amplifier is made up of 100 mΩ signal power and 1 mΩ noise power. The amplifier contributes an additional 100 mΩ of noise and has a power gain of 20 dB. The output signal-to-noise ratio is |
| A. | 100 |
| B. | 50 |
| C. | 10 |
| D. | 5 |
| Answer» C. 10 | |
| 2. |
In order to protect a MOSFET against damage from any stray voltage at the gate |
| A. | grounding rings are provided |
| B. | terminals are shorted |
| C. | source terminal is earthed during transit |
| D. | none of these |
| Answer» D. none of these | |
| 3. |
The name field effect is related to the __________ layers of a JFET. |
| A. | depletion |
| B. | drain |
| C. | source |
| D. | gate |
| Answer» B. drain | |
| 4. |
If input frequency is 50 Hz, the frequency of output wave in a half wave diode rectifier circuit is |
| A. | 25 Hz |
| B. | 50 Hz |
| C. | 100 Hz |
| D. | 200 Hz |
| Answer» C. 100 Hz | |
| 5. |
For an amplifier, the coupling method which gives the highest gain in |
| A. | impedance coupling |
| B. | transformer coupling |
| C. | capacitance coupling |
| D. | resistance coupling |
| Answer» C. capacitance coupling | |
| 6. |
Which of the amplifier circuits using junction transistors has the best gain? |
| A. | Common emitter |
| B. | Common base |
| C. | Common collector |
| D. | All above has the same gain |
| Answer» B. Common base | |
| 7. |
To obtain very high input and O/P impedance in a feedback amplifier, the type of feedback utilized |
| A. | voltage series |
| B. | current series |
| C. | voltage shunt |
| D. | current shunt |
| Answer» C. voltage shunt | |
| 8. |
The thermal resistance of a BJT is about |
| A. | 100 C/W |
| B. | 200 C/W |
| C. | 20 C/W |
| D. | 2 C/W |
| Answer» C. 20 C/W | |
| 9. |
Oscillator with best frequency stability is |
| A. | Crystal oscillator |
| B. | Phase shift oscillator |
| C. | Clapp oscillator |
| D. | Hartley oscillator |
| Answer» B. Phase shift oscillator | |
| 10. |
The IF amplifier in a superheterodyne receiver is |
| A. | single-stage single-timed amplifier |
| B. | two stage of single tuned amplifier |
| C. | double tuned amplifier |
| D. | class-C amplifier |
| Answer» C. double tuned amplifier | |
| 11. |
Cross-over distortion behaviour is a characteristic of |
| A. | class A output stage |
| B. | class B output stage |
| C. | class AB output stage |
| D. | common base output stage |
| Answer» C. class AB output stage | |
| 12. |
The advantage of using crystal oscillator is that it |
| A. | requires low d.c. supply voltage |
| B. | works at high frequency |
| C. | gives high output voltage |
| D. | gives constant frequency of oscillations |
| Answer» E. | |
| 13. |
A transistor will operate in inverted region when |
| A. | emitter junction is forward biased and collector junction is reverse biased |
| B. | emitter junction is reverse biased and collector junction is forward biased |
| C. | emitter junction as well as collector junction are forward biased |
| D. | emitter junction as well as collector junction are reverse biased |
| Answer» C. emitter junction as well as collector junction are forward biased | |
| 14. |
The advantage of Weinbridge oscillator over the phase shift oscillator is that oscillator the frequency may be varied over a range of |
| A. | 1 : 2 |
| B. | 1 : 3 |
| C. | 1 : 5 |
| D. | 1 : 10 |
| Answer» E. | |
| 15. |
In figure the input and output Miller capacitances are |
| A. | 0.25 F each |
| B. | 500 pF each |
| C. | 0.25 F and 500 pF respectively |
| D. | 500 pF and 0.25 F respectively |
| Answer» B. 500 pF each | |
| 16. |
A feedback network to be used with an amplifier to provide oscillation is tested and found to give an output of 0.124 V with a 0.5 V input. What percentage negative feedback should be introduced to the amplifier so that linear oscillations result? |
| A. | 1.25% |
| B. | 2.50% |
| C. | -1.25% |
| D. | -2.5% |
| Answer» D. -2.5% | |
| 17. |
An inverting amplifier has R1 = 10 kΩ, and Rf = 150 kΩ then the O/P voltage, if input voltage Vi = 1 volt. |
| A. | -15 V |
| B. | -10 V |
| C. | 15 V |
| D. | -14 V |
| Answer» B. -10 V | |
| 18. |
Figure uses 10 V zener diode. The minimum and maximum current through series resistance are |
| A. | 10 mA and 30 mA |
| B. | 20 mA and 40 mA |
| C. | 0 and 30 mA |
| D. | 0 and 40 mA |
| Answer» B. 20 mA and 40 mA | |
| 19. |
Ultra high frequency oscillators work in the range |
| A. | 20 Hz to 20 kHz |
| B. | 1 kHz to 30 kHz |
| C. | 30 kHz to 30 MHz |
| D. | above 30 MHz |
| Answer» E. | |
| 20. |
N-channel FETs are superior to p-channel FETs because |
| A. | mobility of electrons is smaller than that of holes |
| B. | mobility of electrons is greater than that of holes |
| C. | they consume less power |
| D. | they have high switching time |
| Answer» C. they consume less power | |
| 21. |
Voltage VL in the circuit when Vs < 0 where D is an ideal diode. (Take R1 = Rs = RL = 1 &ohm;) |
| A. | 0 |
| B. | 1 |
| C. | 1.5 |
| D. | cannot find |
| Answer» B. 1 | |
| 22. |
The most common method for biasing a JFET is |
| A. | reverse bias |
| B. | self bias |
| C. | voltage divider bias |
| D. | none of the above |
| Answer» C. voltage divider bias | |
| 23. |
Consider the following statementsA totem pole configuration used in the output stage if an op-amp has the advantage of using Only n-p-n BJTsComplementary symmetrical pair of transistorsOnly one transistor Which of these statements is/are correct? |
| A. | 1 alone |
| B. | 2 alone |
| C. | 3 alone |
| D. | 1 and 3 |
| Answer» B. 2 alone | |
| 24. |
Assertion (A): An op-amp amplifier can amplify dc signalReason (R): An op-amp amplifier is a direct coupled amplifier |
| A. | Both A and R are correct and R is correct explanation for A |
| B. | Both A and R are correct but R is not correct explanation for A |
| C. | A is correct R is wrong |
| D. | A is wrong R is correct |
| Answer» B. Both A and R are correct but R is not correct explanation for A | |
| 25. |
Which of the following figures is an ideal equivalent circuit of a n-p-n transistor? |
| A. | figure A |
| B. | figure B |
| C. | figure C |
| D. | none |
| Answer» C. figure C | |
| 26. |
In CE amplifier the base current is very high. |
| A. | True |
| B. | False |
| Answer» C. | |
| 27. |
In the graphical analysis of CE amplifier circuit, the upper end of load line is called |
| A. | saturation point |
| B. | cut off point |
| C. | Q point |
| D. | none of the above |
| Answer» B. cut off point | |
| 28. |
A full wave rectifier supplies a load of 1 k&ohm;. The a.c. Voltage applied to the diodes is 220 - 0 - 220 Volts rms. If diode resistance is neglected, then Average d.c. Voltage |
| A. | 220 V |
| B. | 200 V |
| C. | 198 V |
| D. | 0 volts |
| Answer» D. 0 volts | |
| 29. |
Consider 49 cascaded amplifiers having individual rise time as 2 n sec. 3 n sec. ... 50 n sec. The input waveform rise time is 1 n sec. Then the output signal rise time is given time by (Assume output signal rise time is measured within 10 percent range of the final output signal.) |
| A. | 39 - 28 sec |
| B. | 2.28 sec |
| C. | 0.228 sec |
| D. | 39.28 sec |
| Answer» D. 39.28 sec | |
| 30. |
A virtual ground is a ground for |
| A. | voltage |
| B. | current |
| C. | both voltage and current |
| D. | voltage but not for current |
| Answer» E. | |
| 31. |
The zener diode in the rectangular circuit shown in the figure has a zener voltage of 5.8 volts and a zener knee current of 0.5 mA. The maximum load current drawn from this circuit ensuring proper functioning over the input voltage range between 20 and 30 volts, is |
| A. | 23.7 mA |
| B. | 14.2 mA |
| C. | 13.7 mA |
| D. | 24.2 mA |
| Answer» E. | |
| 32. |
In figure, ID = 4 mA. Then VDS = |
| A. | 20 V |
| B. | 16 V |
| C. | 4 V |
| D. | 0.4 V |
| Answer» D. 0.4 V | |
| 33. |
In figure, V0 = |
| A. | 20 V |
| B. | 10 V |
| C. | 5 V |
| D. | 0 |
| Answer» E. | |
| 34. |
The output impedance of an ideal op-amp is |
| A. | zero |
| B. | low |
| C. | high |
| D. | infinite |
| Answer» B. low | |
| 35. |
As compared to a full wave diode rectifier circuit using centre tapped transformer, the bridge diode rectifier circuit has the main advantage of |
| A. | higher current carrying capacity |
| B. | higher efficiency |
| C. | lower ripple factor |
| D. | lower PIV |
| Answer» E. | |
| 36. |
It is desired to reduce distortion in a CE amplifier circuit. We should |
| A. | reduce emitter current |
| B. | reduce collector current |
| C. | reduce ac base voltage |
| D. | reduce base emitter voltage |
| Answer» E. | |
| 37. |
In the circuit of figure = 50 and VBE = 0.5 V. The quiescent value of base current IB is |
| A. | about 28 A |
| B. | about 28 mA |
| C. | about 0.28 A |
| D. | about 2.8 A |
| Answer» B. about 28 mA | |
| 38. |
For a push pull circuit the most favoured biasing method is |
| A. | self bias |
| B. | emitter bias |
| C. | diode bias |
| D. | collector bias |
| Answer» D. collector bias | |
| 39. |
In feedback amplifier the closed loop gain is nearly independent of open loop gain and depends only on the feedback factor. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 40. |
In a N-P-N transistor, when emitter junction is forward biased and collector junction is reverse biased, the transistor will operate in |
| A. | active region |
| B. | saturation region |
| C. | cut of region |
| D. | inverted region |
| Answer» B. saturation region | |
| 41. |
A voltage tripler circuit and voltage quadrupler circuit use identical components. Then |
| A. | voltage regulation in both circuits will be same |
| B. | voltage regulation in both may or may not be same |
| C. | voltage regulation in quadrupler circuit will be better than in tripler circuit |
| D. | voltage regulation in quadrupler circuit will be poorer than in tripler circuit |
| Answer» E. | |
| 42. |
A Ge diode operated at a junction temperature of 27 C. For a forward current of 10 mA, VD is found to be 0.3 V. If VD = 0.4 V then forward current will be |
| A. | 400 mA |
| B. | 475 mA |
| C. | 477 mA |
| D. | 480 mA |
| Answer» D. 480 mA | |
| 43. |
In a power amplifier the collector current flows for 270 of the input cycle. The operations is |
| A. | class A |
| B. | class B |
| C. | class AB |
| D. | class C |
| Answer» D. class C | |
| 44. |
An amplifier has input impedance of 4 k&ohm; and output impedance of 80 k&ohm;. It is used in negative feedback circuit with 10% feedback. If open loop gain is 90, the closed loop input and output impedances are |
| A. | 40 kΩ and 8 kΩ respectively |
| B. | 4 kΩ and 80 kΩ respectively |
| C. | 0.4 kΩ and 800 kΩ respectively |
| D. | 8 kΩ and 160 kΩ respectively |
| Answer» B. 4 kΩ and 80 kΩ respectively | |
| 45. |
In figure the current through resistor R |
| A. | is always equal to 130 mA |
| B. | may vary between 130 mA and 10 mA |
| C. | may vary between 65 mA and 10 mA |
| D. | is always equal to 65 mA |
| Answer» B. may vary between 130 mA and 10 mA | |
| 46. |
A CB amplifier has a = 0.98 and RL = 600 &ohm;. If IE = 3.5 mA, the current gain is |
| A. | 1 |
| B. | 0.98 |
| C. | 0.98 x 3.5 |
| D. | <img src="/_files/images/electronics-and-communication-engineering/analog-electronics/321-316-1.png"> |
| Answer» C. 0.98 x 3.5 | |
| 47. |
funity of an op-amp is about 1 kHz. |
| A. | True |
| B. | False |
| Answer» C. | |
| 48. |
Assertion (A): In an RC coupled amplifier the junction capacitances can be neglected at low frequencies but not at high frequenciesReason (R): Capacitive reactance is inversely proportional to frequency. |
| A. | Both A and R are correct and R is correct explanation for A |
| B. | Both A and R are correct but R is not correct explanation for A |
| C. | A is correct R is wrong |
| D. | A is wrong R is correct |
| Answer» B. Both A and R are correct but R is not correct explanation for A | |
| 49. |
In a full wave rectifier circuit using centre tapped transformer, the peak voltage across half of the secondary winding is 30 V. Then PIV is |
| A. | 30 V |
| B. | 60 V |
| C. | 15 V |
| D. | 10 V |
| Answer» C. 15 V | |
| 50. |
For dc the current through coupling capacitor in CE amplifier circuit is |
| A. | very high |
| B. | high |
| C. | low |
| D. | zero |
| Answer» E. | |