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. |
Assertion (A): In class A amplifier the distortion is minimumReason (R): In class A amplifier collector current exists for 360° of input cycle |
| 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 | |
| 2. |
In figure the potential of gate terminal is |
| A. | 4 V |
| B. | -4 V |
| C. | 0 |
| D. | 20 V |
| Answer» D. 20 V | |
| 3. |
In voltage amplifiers, the load resistance |
| A. | should be a small as possible |
| B. | should be as large as possible |
| C. | must be equal to output impedance |
| D. | must be half of output impedance |
| Answer» C. must be equal to output impedance | |
| 4. |
The input impedance of op-amp circuit of figure is |
| A. | 120 k ohm |
| B. | 110 k ohm |
| C. | infinity |
| D. | 10 k ohm |
| Answer» E. | |
| 5. |
Assertion (A): In monolithic IC the components are part of one chipReason (R): An op-amp is a high gain dc 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» C. A is correct R is wrong | |
| 6. |
In figure VCC = + 30 V, IC corresponding to Q point is 1 mA. If RC = 5 kΩ and RE = 5 kΩ, VCE corresponding to Q point is |
| A. | 30 V |
| B. | 20 V |
| C. | 25 V |
| D. | 5 V |
| Answer» C. 25 V | |
| 7. |
The Clapp oscillator shown in figure will operate at |
| A. | 4.6 kHz |
| B. | 46 kHz |
| C. | 460 kHz |
| D. | 4600 kHz |
| Answer» D. 4600 kHz | |
| 8. |
A Hartley oscillator uses |
| A. | a tapped capacitor |
| B. | a tapped inductor |
| C. | a tapped inductor for inductive feedback |
| D. | none of the above |
| Answer» D. none of the above | |
| 9. |
A class C amplifier has input frequency of 200 kHz. If width of collector pulses is 0.1 μs, duty cycle is |
| A. | 0.01 |
| B. | 0.02 |
| C. | 0.1 |
| D. | 0.2 |
| Answer» C. 0.1 | |
| 10. |
The open loop gain of an actual op-amp is about 100. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 11. |
To protect the diodes in a rectifier and capacitor input filter circuit it is necessary to use |
| A. | surge resistor |
| B. | surge inductor |
| C. | surge capacitor |
| D. | both (a) and (b) |
| Answer» B. surge inductor | |
| 12. |
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 | |
| 13. |
An ideal op-amp can amplify dc signals |
| A. | 1 |
| B. | |
| C. | 1 only |
| D. | 2 only |
| Answer» B. | |
| 14. |
To draw dc equivalent circuit for a CE amplifier circuit we should |
| A. | Reduce all ac sources to zero |
| B. | Open all capacitors |
| C. | Reduce all ac sources to zero and open all capacitors |
| D. | Reduce all ac sources to zero and short all capacitors |
| Answer» D. Reduce all ac sources to zero and short all capacitors | |
| 15. |
A transistor has a power rating of 8 W for a case temperature of 25°C. If derating factor is 30 mW/°C, the power rating for 55°C, case temperature is |
| A. | 8 W |
| B. | 7.5 W |
| C. | 7.1 W |
| D. | 6.8 W |
| Answer» D. 6.8 W | |
| 16. |
In figure, D1 turns on when |
| A. | vi is more than V1 |
| B. | vi is less than V1 |
| C. | vi is between V1 and V2 |
| D. | none of the above |
| Answer» B. vi is less than V1 | |
| 17. |
In a good voltage amplifier, its input impedance |
| A. | must be high compared to the resistance of the source |
| B. | must be low compared to the resistance of the source |
| C. | must be equal to the resistance of the source |
| D. | must be half the resistance of the source |
| Answer» B. must be low compared to the resistance of the source | |
| 18. |
Assertion (A): The duty cycle of a class C amplifier affects the power dissipation of transistorReason (R): At higher harmonics the efficiency of a class C amplifier becomes poor |
| 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» C. A is correct R is wrong | |
| 19. |
Which of the following power amplifiers has highest efficiency? |
| A. | Class A |
| B. | Class AB |
| C. | Class B |
| D. | Class C |
| Answer» E. | |
| 20. |
The gate electrode in the FET corresponds to the |
| A. | collector in a bipolar transistor |
| B. | base in a bipolar transistor |
| C. | emitter in a bipolar transistor |
| D. | none of the above |
| Answer» C. emitter in a bipolar transistor | |
| 21. |
Low gain-bandwidth product of a JFET is due to |
| A. | reduced number of holes |
| B. | junction capacitive effects |
| C. | low degree of isolation between input and output |
| D. | all of the above |
| Answer» C. low degree of isolation between input and output | |
| 22. |
When load is coupled to class A amplifier through transformer, efficiency decreases. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 23. |
In a transistor leakage current mainly depends on |
| A. | doping of base |
| B. | size of emitter |
| C. | rating of transistor |
| D. | temperature |
| Answer» E. | |
| 24. |
In the case of an amplifier, the normalised voltage gain is given by.where f0 is zero frequency, fP is pole frequency. For a standard frequency response of the amplifier, |
| A. | fP >> f0 |
| B. | fP = f0 |
| C. | fP << f0 |
| D. | f0 = 2 fP |
| Answer» B. fP = f0 | |
| 25. |
In a resistance loaded amplifier, the gain decreases at high frequencies because |
| A. | decreasing reactance of the stray CT |
| B. | increasing reactance of the stray CT |
| C. | increasing reactance of CT |
| D. | decreasing reactance of CT |
| Answer» B. increasing reactance of the stray CT | |
| 26. |
In figure the voltage drop across diode is 0.7 V. Then the voltage across diode during negative half cycle is |
| A. | 10 V |
| B. | 9.3 V |
| C. | zero |
| D. | 10.7 V |
| Answer» B. 9.3 V | |
| 27. |
In the graphical analysis of an amplifier circuit, the slope of dc load line depends on |
| A. | load resistance only |
| B. | collector supply voltage only |
| C. | both load resistance and collector supply voltage |
| D. | none of the above |
| Answer» B. collector supply voltage only | |
| 28. |
Which circuit has its output signal from, the emitter? |
| A. | Common base |
| B. | Common emitter |
| C. | Emitter follower |
| D. | None of the above |
| Answer» D. None of the above | |
| 29. |
In a CE amplifier circuit the ac voltage between emitter and ground |
| A. | is very high |
| B. | may be high or low |
| C. | is zero |
| D. | depends on circuit configuration |
| Answer» D. depends on circuit configuration | |
| 30. |
If an amplifier with gain of - 1000 and feedback factor β = - 0.1 had a gain change of 20% due to temperature, the change in gain of the feedback amplifier would be |
| A. | 0.1 |
| B. | 0.05 |
| C. | 0.002 |
| D. | 0.0001 |
| Answer» D. 0.0001 | |
| 31. |
Assertion (A): CE amplifier is the most widely used BJT amplifierReason (R): CE amplifier has zero phase difference between input and output |
| 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» D. A is wrong R is correct | |
| 32. |
The depletion type MOSFET can operate in |
| A. | depletion mode only |
| B. | enhancement mode only |
| C. | depletion or enhancement mode |
| D. | neither depletion nor enhancement mode |
| Answer» D. neither depletion nor enhancement mode | |
| 33. |
In figure, voltage across R2 = + 10 V. If VBE = 0.7 V and VE = 0.7 V and RE = 10 kΩ, current through RE is |
| A. | 1 mA |
| B. | 0.93 mA |
| C. | 2 mA |
| D. | 1.86 mA |
| Answer» C. 2 mA | |
| 34. |
The open loop gain of an amplifier is 200. If negative feedback with β = 0.2 is used, the closed loop gain will be |
| A. | 200 |
| B. | 40.12 |
| C. | 4.878 |
| D. | 2.2 |
| Answer» D. 2.2 | |
| 35. |
In figure the zener current |
| A. | is always 130 mA |
| B. | may vary between 10 mA and 130 mA |
| C. | may vary between 60 mA and 130 mA |
| D. | is always equal to 65 mA |
| Answer» C. may vary between 60 mA and 130 mA | |
| 36. |
In high frequency region, an amplifier behaves like a |
| A. | band pass filter |
| B. | low pass filter |
| C. | high pass filter |
| D. | any of the above |
| Answer» C. high pass filter | |
| 37. |
A radio frequency choke permits an easy flow of __________ current and at the same time it offers a very impedance to __________ currents. |
| A. | A.C., low frequency |
| B. | A.C., high frequency |
| C. | D.C., low frequency |
| D. | D.C. high frequency |
| Answer» E. | |
| 38. |
High cut off frequency can be expected in case of |
| A. | common-base |
| B. | common-emitter |
| C. | common-collector |
| D. | all of the above |
| Answer» D. all of the above | |
| 39. |
Negative feedback reduces noise originating at the amplifier input. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 40. |
The ripple factor of a half wave rectifier is more than 2. |
| A. | 1 |
| B. | |
| C. | Both A and R are correct and R is correct explanation for A |
| D. | Both A and R are correct but R is not correct explanation for A |
| Answer» C. Both A and R are correct and R is correct explanation for A | |
| 41. |
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 | |
| 42. |
When the ac base voltage in a CE amplifier circuit is too high, the ac emitter current is |
| A. | zero |
| B. | constant |
| C. | alternating |
| D. | distorted |
| Answer» E. | |
| 43. |
Which of the following statement is false? |
| A. | The zener diode is uses as a constant voltage source |
| B. | The SCR is a silicon rectifier with a gate electrode to control when current flows from cathode to anode |
| C. | The gate electrode in the FET corresponds to the collector in a bipolar transistor |
| D. | None of the above |
| Answer» E. | |
| 44. |
Two identical FETs, each characterised by the parameters gm and rd are connected in parallel. The composite FET is then characterised by the parameters |
| A. | and 2rd |
| B. | and |
| C. | 2gm and |
| D. | 2gm and 2rd |
| Answer» D. 2gm and 2rd | |
| 45. |
The input impedance of a non-inverting amplifier is very low. |
| A. | 1 |
| B. | |
| C. | 1 kHz |
| D. | 10 kHz |
| Answer» C. 1 kHz | |
| 46. |
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. | 0.0125 |
| B. | 0.025 |
| C. | -0.0125 |
| D. | -0.025 |
| Answer» D. -0.025 | |
| 47. |
DC amplifiers have a tendency to be unstable. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 48. |
The more negative gate voltage, the conductive channel becomes |
| A. | narrower |
| B. | wider |
| C. | thicker |
| D. | linear |
| Answer» B. wider | |
| 49. |
In figure, V0 = |
| A. | zero |
| B. | 5.7 V |
| C. | 6.9 V |
| D. | 12.6 V |
| Answer» D. 12.6 V | |
| 50. |
The P-type substrate in a conventional pn Junction isolated integrated circuits should be connected to |
| A. | any where |
| B. | a dc ground potential |
| C. | the most positive potential available in the circuit |
| D. | the most negative potential available in the circuit |
| Answer» D. the most negative potential available in the circuit | |