MCQOPTIONS
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MCQOPTIONS
This section includes 2171 Mcqs, each offering curated multiple-choice questions to sharpen your ENGINEERING SERVICES EXAMINATION (ESE) knowledge and support exam preparation. Choose a topic below to get started.
| 1151. |
Wien bridge uses |
| A. | lead network |
| B. | lag network |
| C. | lead-lag network |
| D. | Both (a) and (b) |
| Answer» D. Both (a) and (b) | |
| 1152. |
A bipolar transistor is a __________ controlled devices whereas a FET is a __________ controlled devices. |
| A. | current, voltage |
| B. | current, current |
| C. | voltage, current |
| D. | voltage, voltage |
| Answer» B. current, current | |
| 1153. |
An engineer designs an amplifier to have a voltage gain of 60, but when constructed it only had a gain of 50. What percentage of feedback will cause oscillations? |
| A. | 0.1% |
| B. | 0.5% |
| C. | 1% |
| D. | 2% |
| Answer» E. | |
| 1154. |
Which of the following can be used to isolate a low impedance from a high impedance source? |
| A. | Emitter follower |
| B. | π filter |
| C. | Darlington pair |
| D. | Any of the above |
| Answer» D. Any of the above | |
| 1155. |
The properties of JFET resemble those of |
| A. | thermionic values |
| B. | N-P-N transistors |
| C. | P-N-P transistors |
| D. | unijunction transistor |
| Answer» C. P-N-P transistors | |
| 1156. |
A complementary symmetry amplifier has |
| A. | 1 P-N-P and 1 N-P-N transistor |
| B. | 2 P-N-P transistor |
| C. | 2 N-P-N transistor |
| D. | 2 P-channel FETs |
| Answer» B. 2 P-N-P transistor | |
| 1157. |
In figure the collector to emitter breakdown voltage of the transistor (βV(CEO)) should be |
| A. | more than VCC |
| B. | more than 0.5 VCC |
| C. | more than VCC + E |
| D. | more than 2 VCC |
| Answer» C. more than VCC + E | |
| 1158. |
Which class of amplifiers operates with least distortion? |
| A. | Class A |
| B. | Class B |
| C. | Class C |
| D. | Class AB |
| Answer» B. Class B | |
| 1159. |
Which configuration is suitable for impedance matching? |
| A. | CB |
| B. | CE |
| C. | CC |
| D. | CB and CE |
| Answer» D. CB and CE | |
| 1160. |
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 | |
| 1161. |
In CE circuit the parameter f12 is very small. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 1162. |
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 | |
| 1163. |
RC network shown in the given figure can provide a maximum theoretical phase shift of |
| A. | 90° |
| B. | 180° |
| C. | 270° |
| D. | 360° |
| Answer» C. 270° | |
| 1164. |
For a system to work, as oscillator the total phase shift of the loop gain must be equal to |
| A. | 90° |
| B. | 45° |
| C. | 270° |
| D. | 360° |
| Answer» E. | |
| 1165. |
The disadvantage of transformer coupling in amplifier is |
| A. | cost of transformer at audio frequencies |
| B. | size of transformer at audio frequencies |
| C. | size of transformer at radio frequencies |
| D. | cost and size of transformer at audio frequencies |
| Answer» E. | |
| 1166. |
Harmonic distortion in CB amplifier may be least when the load resistance is |
| A. | negligible |
| B. | very low |
| C. | very high |
| D. | infinite |
| Answer» D. infinite | |
| 1167. |
The input to an op-amp integrating amplifier is a constant voltage. The output will be |
| A. | a constant voltage |
| B. | a sawtooth wave |
| C. | a ramp |
| D. | ac voltage |
| Answer» E. | |
| 1168. |
V MOS have the advantage of |
| A. | faster switching |
| B. | no thermal run away |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» D. none of the above | |
| 1169. |
A 741 type op-amp has a gain bandwidth product of 1 MHz. A non-inverting amplifier using this op-amp and having a voltage gain of 20 dB will exhibit a -3dB bandwidth of |
| A. | 50 kHz |
| B. | 100 kHz |
| C. | 1000/17 kHz |
| D. | 1000/7.07 kHz |
| Answer» C. 1000/17 kHz | |
| 1170. |
A transistor amplifier is operating in class A mode. If a transformer is connected for impedance matching, the efficiency will |
| A. | increase |
| B. | decrease |
| C. | not be affected |
| D. | increase or decrease |
| Answer» B. decrease | |
| 1171. |
Most of the transistor data sheets specify the power rating for an ambient temperature of |
| A. | 10°C |
| B. | 25°C |
| C. | 50°C |
| D. | 75°C |
| Answer» C. 50°C | |
| 1172. |
If re is ac resistance of diode, the Thevenin input impedance of a differential amplifier is |
| A. | re |
| B. | bre |
| C. | 2 bre |
| D. | 0.5 bre |
| Answer» D. 0.5 bre | |
| 1173. |
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 | |
| 1174. |
In each of circuits below, indicate which diode is conducting? |
| A. | Figure A |
| B. | Figure B |
| C. | Figure C |
| D. | All the three |
| Answer» E. | |
| 1175. |
A clamper |
| A. | adds a dc component to the input signal |
| B. | removes signal voltages above or below a specified value |
| C. | both (a) and (b) |
| D. | either (a) or (b) |
| Answer» D. either (a) or (b) | |
| 1176. |
In a CE amplifier the ac cut off voltage is 9 V and slope of ac load line is - 0.5 mA/V. The ac saturation current is |
| A. | 9 mA |
| B. | 4.5 mA |
| C. | 3 mA |
| D. | 18 mA |
| Answer» C. 3 mA | |
| 1177. |
An amplifier signal is made up of just two frequencies 1000 Hz. The output signal consists of 500 Hz and 25000 Hz frequencies. This may be attributed to |
| A. | harmonic distortion |
| B. | intermodulation distortion |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» C. both (a) and (b) | |
| 1178. |
A cascade amplifier stage is equivalent to |
| A. | common emitter stage followed by a common base stage |
| B. | common base stage followed by an emitter follower |
| C. | an emitter follower stage followed by a common base stage |
| D. | a common base stage followed by a common emitter stage |
| Answer» B. common base stage followed by an emitter follower | |
| 1179. |
The re model equivalent circuit shown in figure is for |
| A. | CE amplifier |
| B. | CC amplifier |
| C. | CB amplifier |
| D. | None of the above |
| Answer» D. None of the above | |
| 1180. |
In a transistor push pull amplifier |
| A. | there is no dc present in the output |
| B. | there are no even harmonics in the output |
| C. | both (a) and (b) |
| D. | neither (a) nor (b) |
| Answer» D. neither (a) nor (b) | |
| 1181. |
For a BJT if β = 50, ICEO = 3 μA and IC = 1.2 mA then IB |
| A. | 24 μA |
| B. | 23 μA |
| C. | 20 μA |
| D. | 10 μA |
| Answer» B. 23 μA | |
| 1182. |
Assertion (A): In a push pull circuit each transistor stays in the active region for one half cycleReason (R): A push pull amplifier has low distortion |
| 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 | |
| 1183. |
In figure gain bandwidth product is |
| A. | 200 Hz |
| B. | 200 MHz |
| C. | 200 kHz |
| D. | 2 MHz |
| Answer» D. 2 MHz | |
| 1184. |
For the circuit of figure the input and output Miller resistances are |
| A. | 5 kΩ each |
| B. | 1 ohm and 5 kΩ respectively |
| C. | 5 kΩ and 1 ohm respectively |
| D. | 1 ohm each |
| Answer» C. 5 kΩ and 1 ohm respectively | |
| 1185. |
In figure, the function of resistor R is |
| A. | to reduce ripples in the output |
| B. | to improve voltage regulation |
| C. | to limit the surge current |
| D. | either (a) or (c) |
| Answer» D. either (a) or (c) | |
| 1186. |
Class A amplifiers are preferred when |
| A. | minimum distortion is required |
| B. | maximum voltage gain is required |
| C. | output signal is desired in phase with input signal |
| D. | signal having A.C. superimposed on D.C. are to be amplified |
| Answer» B. maximum voltage gain is required | |
| 1187. |
Calculate the conductivity of pure silicon at room temperature when the concentration of carriers is 1.6 x 10¹ᴼ per cm³. Take μe = 1500 cm²/V-sec, μh = 500 cm²/V-sec at room temperature, |
| A. | 5.12 x 10¯¹⁶ |
| B. | 5 x 10¹⁶ |
| C. | 10¹⁶ |
| D. | 5 x 10²ᴼ |
| Answer» B. 5 x 10¹⁶ | |
| 1188. |
Generally op amp is used in |
| A. | open loop |
| B. | closed loop |
| C. | cascaded loop |
| D. | either (a) or (c) |
| Answer» C. cascaded loop | |
| 1189. |
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% | |
| 1190. |
In a Darlington pair |
| A. | the emitter of first transistor drives the base of the second |
| B. | the base of the first transistor drives the emitter of the second |
| C. | emitters of the two transistors are connected through a resistor |
| D. | none of the above |
| Answer» B. the base of the first transistor drives the emitter of the second | |
| 1191. |
The open loop gain of an actual op-amp is about 100. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» C. May be True or False | |
| 1192. |
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 | |
| 1193. |
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. | |
| 1194. |
Which connection is rarely used? |
| A. | CE |
| B. | CB |
| C. | CC |
| D. | Both (a) and (b) |
| Answer» C. CC | |
| 1195. |
A certain transistor has αdc of 0.98 and a collectors leakage current of 5 μA. If IE = 1 mA, the collector current will be |
| A. | 1.005 mA |
| B. | 0.985 mA |
| C. | 0.975 mA |
| D. | 0.955 mA |
| Answer» C. 0.975 mA | |
| 1196. |
If input ac is 10 Vrms, then maximum voltage that will appear across the diode of a half wave rectifier with a capacitor I/P filter will be |
| A. | 10 V |
| B. | 14 V |
| C. | 20 V |
| D. | 28 V |
| Answer» C. 20 V | |
| 1197. |
An ideal op-amp can amplify dc signals |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 1198. |
The open loop gain of an ideal op-amp is |
| A. | infinite |
| B. | very high |
| C. | neither high nor low |
| D. | low |
| Answer» B. very high | |
| 1199. |
If a class C power amplifier has an input signal with frequency of 200 kHz and the width of collector current pulses of 0.1 ms, then the duty cycle of the amplifier will be |
| A. | 1% |
| B. | 2% |
| C. | 10% |
| D. | 20% |
| Answer» E. | |
| 1200. |
JFET is also known as |
| A. | linear device |
| B. | square law device |
| C. | inverse law device |
| D. | logarithmic law device |
| Answer» C. inverse law device | |