MCQOPTIONS
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MCQOPTIONS
This section includes 521 Mcqs, each offering curated multiple-choice questions to sharpen your Physical Electronics Devices and ICs knowledge and support exam preparation. Choose a topic below to get started.
| 251. |
In a PN-junction diode, holes diffuse from the P region to the N region because |
| A. | The free electrons in the N region attracted them |
| B. | They are swept across the junction by the potential difference |
| C. | There is greater concentration of holes in the P region as compared to N region |
| D. | None of the above |
| Answer» D. None of the above | |
| 252. |
In an unbiased PN-junction, the junction current at equilibrium is |
| A. | Due to diffusion of minority carriers only |
| B. | Due to diffusion of majority carriers only |
| C. | Zero, because equal but opposite carriers crossing the junction |
| D. | Zero, because no charges are crossing the junction |
| Answer» D. Zero, because no charges are crossing the junction | |
| 253. |
The potential barrier at a PN-junction is due to the charges on either side of the junction. These charges are |
| A. | Minority carriers |
| B. | Majority carriers |
| C. | Both majority and minority carriers |
| D. | FIxed donor and acceptor ions |
| Answer» E. | |
| 254. |
When forward bias is applied to a junction diode, it |
| A. | Increases the potential barrier |
| B. | Decreases the potential barrier |
| C. | Reduces the majority-current to zero |
| D. | Reduces the minority-carrier current to zero |
| Answer» C. Reduces the majority-current to zero | |
| 255. |
The reverse saturation current in a junction diode is the current that flows when |
| A. | Only majority carriers are crossing the junction |
| B. | Only minority carriers are crossing the junction |
| C. | The junction is unbiased |
| D. | The potential barriers is zero |
| Answer» C. The junction is unbiased | |
| 256. |
Match List I with List II and select the correct answer using the codes given below the lists |
| A. | 1122 |
| B. | 1212 |
| C. | 1221 |
| D. | 2211 |
| Answer» D. 2211 | |
| 257. |
The output waveform will be |
| A. | <img src="http://images.interviewmania.com/wp-content/uploads/2019/05/77A1.png%20"> |
| B. | <img src="http://images.interviewmania.com/wp-content/uploads/2019/05/77B.png"> |
| C. | <img src="http://images.interviewmania.com/wp-content/uploads/2019/05/77C.png%20"> |
| D. | <img src="http://images.interviewmania.com/wp-content/uploads/2019/05/77D.png"> |
| Answer» E. | |
| 258. |
The emitter region in the p-n-p junction transistor is more heavily doped than the base region so that |
| A. | The flow across the base region will be mainly because of electron |
| B. | The flow across the base region will be mainly because of holes |
| C. | Recombination will be increased in the base region |
| D. | Base current will be high |
| Answer» C. Recombination will be increased in the base region | |
| 259. |
In a half-wave rectifier, the load current flows for |
| A. | The complete cycle of the input signal |
| B. | Only of the positive half-cycle of the input signal |
| C. | Less than half cycle of the input signal |
| D. | Zero time |
| Answer» C. Less than half cycle of the input signal | |
| 260. |
The capacitance of a reverse-biased pn-junction |
| A. | Increases as the reverse bias is decreased |
| B. | Increases as the reverse bias is increased |
| C. | Depends mainly on the reverse saturation current |
| D. | Makes the pn-junction more effective at high frequencies |
| Answer» B. Increases as the reverse bias is increased | |
| 261. |
The barrier capacitance C |
| A. | Increases with the width of the space charge layer |
| B. | Increases with increasing reverse voltage |
| C. | Is due to the immobile charges at the junction varying with the applied voltage |
| D. | Can be defined as Q/V |
| Answer» D. Can be defined as Q/V | |
| 262. |
When reverse bias is applied to a pn-junction |
| A. | The barrier potential is decreased |
| B. | Majority carriers flow down the potential |
| C. | Thermally-generated minority carriers are responsible for the saturation current |
| D. | Minority carriers are holes from p-side moving to the n-side |
| Answer» D. Minority carriers are holes from p-side moving to the n-side | |
| 263. |
At the junction of a pn-diode |
| A. | The depletion region has an electrostatic potential which makes p-side positive with respect to the n-side |
| B. | The space charge region exists predominantly in the heavily doped junction |
| C. | Holes are prevented from diffusing from n-side to the p-side |
| D. | The electric field at the junction is of such value as to cause the diffusive tendency to be counterbalanced by the drift velocity of electrons and holes |
| Answer» E. | |
| 264. |
In a p-type semiconductor |
| A. | The hole concentration is less the electron concentration |
| B. | Electrons are the majority carriers |
| C. | At room temperature the hole concentration equals the acceptor concentration |
| D. | Electron density does not change with temperature |
| Answer» D. Electron density does not change with temperature | |
| 265. |
For transistor action |
| A. | The collector must be more heavily doped than the emitter region |
| B. | The collector-base junction must be forward-biased |
| C. | The base region must be very narrow |
| D. | The base region must be n-type material |
| Answer» D. The base region must be n-type material | |
| 266. |
The symbol I |
| A. | In the reverse direction to the collector junction with the emitter open-circuited |
| B. | In the forward direction to the collector junction with the emitter open-circuited |
| C. | In the reverse direction to the emitter junction with the collector open-circuited |
| D. | In the forward direction to the emitter junction with the collector open-circuited |
| Answer» B. In the forward direction to the collector junction with the emitter open-circuited | |
| 267. |
The current I |
| A. | Is generally greater in silicon than in germanium transistors |
| B. | Depends largely on the emitter-base junction bias |
| C. | Depends largely on the emitter doping |
| D. | Increases with an increase in temperature |
| Answer» E. | |
| 268. |
The main current crossing the collection junction in a normally biased NPN transistor is |
| A. | A diffusion current |
| B. | A drift current |
| C. | A hole current |
| D. | Equal to the base current |
| Answer» C. A hole current | |
| 269. |
In a PNP transistor, electons flow |
| A. | Out of the transistor at the collector and base leads |
| B. | Into the transistor at the emitter and base leads |
| C. | Into the transistor at the collector and base leads |
| D. | Out of the transistor at the emitter and base leads |
| Answer» D. Out of the transistor at the emitter and base leads | |
| 270. |
In a metal |
| A. | The electrical conduction is by electrons and holes |
| B. | With rise in temperature, the conductivity decreases |
| C. | The conduction band is empty |
| D. | There is a small energy gap between the two bands |
| Answer» C. The conduction band is empty | |
| 271. |
The input and output signals of a common-emitter amplifier are |
| A. | Always equal |
| B. | Out of phase |
| C. | Always negative |
| D. | In phase |
| Answer» C. Always negative | |
| 272. |
A transistor, when connected in common-emitter mode, has |
| A. | A high inputresistance and a low output resistance |
| B. | A medium input resistance and a high output resistance |
| C. | Very low input resistance and a low output resistance |
| D. | A high input resistance and a high output resistance |
| Answer» C. Very low input resistance and a low output resistance | |
| 273. |
Compared to a CB amplifier has |
| A. | Lower input resistance |
| B. | higher input resistance |
| C. | Lower current amplification |
| D. | Higher current amplification |
| Answer» E. | |
| 274. |
A transistor connected in common-base configuration has |
| A. | A low input resistance and high output resistance |
| B. | A low input resistance and a low output resistance |
| C. | A low input resistance and a low output resistance |
| D. | A high input resistance and a high output resistance |
| Answer» B. A low input resistance and a low output resistance | |
| 275. |
The high resistance of the reverse-biased collector junction is due to the fact that |
| A. | A small change in collector bias voltage causes a large change in collector current. |
| B. | A large change in collector bias voltage causes very little change in collector current. |
| C. | A small change in emitter current causes an almost equal change in collector current. |
| D. | A small change in emitter bias voltage causes a large change in collector current. |
| Answer» C. A small change in emitter current causes an almost equal change in collector current. | |
| 276. |
In regard semiconductor photodiodes the following statements are mode |
| A. | 2, 4 |
| B. | 1, 2 |
| C. | 2, 3 |
| D. | 1, 3 |
| Answer» E. | |
| 277. |
In regard to the reverse biased pn junction photodiode the following statements are made |
| A. | All four |
| B. | (1) and (2) |
| C. | (2) and (4) |
| D. | (1) and (3) |
| Answer» E. | |
| 278. |
Find I |
| A. | <table><tr><td rowspan="2">I<sub>1</sub> =</td> <td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center> 5 V<sub>x</sub></center></td><td rowspan="2"> if 0 < V<sub>S</sub> < 0.7 V and I<sub>1</sub> = I<sub>2</sub> = 1.8 mA if V<sub>S</sub> > .7 V </td></tr><td align="center">2K</td></table> |
| B. | <table><tr><td rowspan="2">I<sub>2</sub> = I<sub>1</sub> =</td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center> 5 V<sub>x</sub></center></td><td rowspan="2"> if V<sub>S</sub> > .7 V I<sub>2</sub> = 1.8 mA if 0 < V<sub>S</sub> < 0.7 V</td></tr><td align="center">2K</td></table> |
| C. | <table><tr><td rowspan="2">I<sub>2</sub> = 1.8 mA if V<sub>S</sub> > 0.7 V I<sub>1</sub> =</td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center> 5 V<sub>x</sub></center></td><td rowspan="2"> if V<sub>S</sub> > 0.7 V</td></tr><td align="center">2K</td></table> |
| D. | None of the above |
| Answer» B. <table><tr><td rowspan="2">I<sub>2</sub> = I<sub>1</sub> =</td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center> 5 V<sub>x</sub></center></td><td rowspan="2"> if V<sub>S</sub> > .7 V I<sub>2</sub> = 1.8 mA if 0 < V<sub>S</sub> < 0.7 V</td></tr><td align="center">2K</td></table> | |
| 279. |
The emitter resistor R |
| A. | Reduces the voltage gain |
| B. | Increases the voltage gain |
| C. | Causes thermal runaway |
| D. | Stabilizes the Q point |
| Answer» E. | |
| 280. |
The Q point in a voltage amplifier is selected in the middle of the active region because |
| A. | It gives a distortionless output |
| B. | The operating point then becomes very stable |
| C. | The circuit then requires less number of resistors |
| D. | It then requires a small dc voltage |
| Answer» B. The operating point then becomes very stable | |
| 281. |
The operating point of an NPN transistor amplifier should not be selected in the saturation region as |
| A. | It may drive the transistor to thermal runaway |
| B. | It may cause output to be clipped in the negative half of the input signal |
| C. | It may cause output to be clipped in the positive half of the input signal |
| D. | It may requird high dc collector supply. |
| Answer» D. It may requird high dc collector supply. | |
| 282. |
The potential-divider method of biasing is used in amplifiers to |
| A. | Limit the input ac signal going to the base |
| B. | Make the operating point almost independent of |
| C. | Reduce the base current |
| D. | Reduce the cost of the circuit |
| Answer» C. Reduce the base current | |
| 283. |
A transistor is operating in the active region. Under this condition |
| A. | Both the junctions are forward-biased |
| B. | Both the junctions are reverse-biased |
| C. | Emitter-base junction is reverse-biased, and collector-base junction is forward-biased |
| D. | Emitter-base junction is forward-biased and collector-base junction is reverse-biased |
| Answer» E. | |
| 284. |
The basic difference between the zener diode and the general diode is |
| A. | Concentration profile (i.e. doping) |
| B. | Applied reverse voltage |
| C. | Applied forward voltage |
| D. | Data is insufficient |
| Answer» B. Applied reverse voltage | |
| 285. |
The JFET in the circuit shown in figure has an I |
| A. | 150 ohm |
| B. | 470 ohm |
| C. | 560 ohm |
| D. | 1 kilo ohm |
| Answer» B. 470 ohm | |
| 286. |
In an FET |
| A. | Both the junction are reverse biased |
| B. | One junction is reverse biased and the other forward biased |
| C. | One junction has reverse biased on both side of the junction |
| D. | One junction has reverse biased on side and forward bias on the other |
| Answer» D. One junction has reverse biased on side and forward bias on the other | |
| 287. |
Best electronic device for fast switching is |
| A. | MOSFET |
| B. | JEFT |
| C. | BJT |
| D. | Diode 1 |
| Answer» B. JEFT | |
| 288. |
The p-channel JFET is complementary to the n-channel JFET and uses |
| A. | Holes instead of electrons for majority carriers |
| B. | Electrons instead of holes for majority carriers |
| C. | Both electrons as well as holes for majority carriers |
| D. | Neither holes nor electrons for majority carriers |
| Answer» B. Electrons instead of holes for majority carriers | |
| 289. |
The input gate current of an FET is |
| A. | A few amperes |
| B. | A few milliamperes |
| C. | A few microamperes |
| D. | Negligible |
| Answer» E. | |
| 290. |
A properly biased JFET will act as a |
| A. | Current controlled current source |
| B. | Current controlled voltage source |
| C. | Voltage controlled voltage source |
| D. | Voltage controlled current source |
| Answer» E. | |
| 291. |
FET tuned amplifier with g |
| A. | 200 |
| B. | 100 |
| C. | 50 |
| D. | 25 |
| Answer» C. 50 | |
| 292. |
Basic function of SiO |
| A. | (ii) only |
| B. | (iii) and (v) only |
| C. | (ii), (iii) and (v) only |
| D. | All |
| Answer» D. All | |
| 293. |
The substrate in a monolithic circuit must be connected to |
| A. | Ground |
| B. | Supply |
| C. | Most negative voltage for p-type substrate |
| D. | Most positive for p-type substrate |
| Answer» D. Most positive for p-type substrate | |
| 294. |
Order of temperature for epitaxial growth is |
| A. | 800 C |
| B. | 2000 C |
| C. | 500 C |
| D. | 1200 C |
| Answer» E. | |
| 295. |
Epitaxial growth in IC chip |
| A. | Growth from liquid phase |
| B. | Can be p-type only |
| C. | Growth from gas phase |
| D. | Can be n-type only |
| Answer» D. Can be n-type only | |
| 296. |
Germanium |
| A. | Can t be purified by zone refling |
| B. | Usually purified by floating zone method |
| C. | More easily purified than Si |
| D. | Has melting point higher than Si |
| Answer» D. Has melting point higher than Si | |
| 297. |
In an Abrupt pn-junction the doping concentrations on the p-side and n-side are N |
| A. | 0.3 m |
| B. | 0.27 m |
| C. | 2.7 m |
| D. | None of these |
| Answer» C. 2.7 m | |
| 298. |
For a circuit containing both pnp and npn transistors the monolithic IC requires |
| A. | 3 layers |
| B. | 5 layers |
| C. | 6 layers |
| D. | 4 layers |
| Answer» D. 4 layers | |
| 299. |
MOSFET can be used as |
| A. | Current controlled capacitor |
| B. | Voltage controlled capacitor |
| C. | Current controlled inductor |
| D. | Voltage controlled inductor |
| Answer» C. Current controlled inductor | |
| 300. |
The NMOS transistor has V |
| A. | 5 , 3 25 k |
| B. | 3 25 k , 5 k |
| C. | 2 5 k , 6 5 k |
| D. | None of these |
| Answer» D. None of these | |