MCQOPTIONS
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MCQOPTIONS
This section includes 451 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.
| 401. |
The power factor at the input terminals of a cyclo- converter is generally |
| A. | low and leading |
| B. | low and lagging |
| C. | high and leading |
| D. | high and lagging |
| Answer» C. high and leading | |
| 402. |
Ripple factor RF and form factor FF are related as |
| A. | RF = FF² - 1 |
| B. | RF = (FF² - 1)^0.5 |
| C. | RF = √FF - 1 |
| D. | RF = (FF - 1)^0.5 |
| Answer» C. RF = √FF - 1 | |
| 403. |
Modified Mc Murray full bridge inverter uses |
| A. | 4 thyristors and 2 diodes |
| B. | 4 thyristors and 4 diodes |
| C. | 8 thyristors and 4 diodes |
| D. | 8 thyristors and 8 diodes |
| Answer» E. | |
| 404. |
In the below figure the average load current is 15 A. The rms value of transformer secondary current is |
| A. | 15 A |
| B. | 10.61 A |
| C. | 7.5 A |
| D. | 14.14 A |
| Answer» C. 7.5 A | |
| 405. |
A dc chopper is feeding an RLE load. The maximum steady state ripple is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 406. |
Figure shows a chopper feeding RLE load, The free wheeling diode conducts when |
| A. | thyristor is on |
| B. | thyristor is off |
| C. | both when thyristor is on and thyristor is off |
| D. | partly when thyristor is off and partly when thyristor is on |
| Answer» C. both when thyristor is on and thyristor is off | |
| 407. |
A single phase half wave rectifier is feeding a resistive load. Input voltage v = Vm sin ωt. The output dc voltage is Vdc and output rms voltage is Vrms . If firing angle is 180°, Vdc and Vrms respectively are |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 408. |
In a single phase full wave converter (M-2 connection) feeding on R - L load, the input voltage is v = Vm sin ωt. The expression for dc output voltage is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» D. D | |
| 409. |
The output characteristics of a MOSFET, is a plot of |
| A. | Id as a function of Vgs with Vds as a parameter |
| B. | Id as a function of Vds with Vgs as a parameter |
| C. | Ig as a function of Vgs with Vds as a parameter |
| D. | Ig as a function of Vds with Vgs as a parameter |
| Answer» C. Ig as a function of Vgs with Vds as a parameter | |
| 410. |
In the transfer characteristics of a MOSFET, the threshold voltage is the measure of the |
| A. | minimum voltage to induce a n-channel/p-channel for conduction |
| B. | minimum voltage till which temperature is constant |
| C. | minimum voltage to turn off the device |
| D. | none of the above mentioned is true |
| Answer» B. minimum voltage till which temperature is constant | |
| 411. |
The controlling parameter in MOSFET is |
| A. | Vds |
| B. | Ig |
| C. | Vgs |
| D. | Is |
| Answer» C. Vgs | |
| 412. |
The arrow on the symbol of MOSFET indicates |
| A. | that it is a N-channel MOSFET |
| B. | the direction of electrons |
| C. | the direction of conventional current flow |
| D. | that it is a P-channel MOSFET |
| Answer» C. the direction of conventional current flow | |
| 413. |
Choose the correct statement |
| A. | MOSFET is a uncontrolled device |
| B. | MOSFET is a voltage controlled device |
| C. | MOSFET is a current controlled device |
| D. | MOSFET is a temperature controlled device |
| Answer» C. MOSFET is a current controlled device | |
| 414. |
Which of the following terminals does not belong to the MOSFET? |
| A. | Drain |
| B. | Gate |
| C. | Base |
| D. | Source |
| Answer» D. Source | |
| 415. |
The MOSFET combines the areas of _______ & _________ |
| A. | field effect & MOS technology |
| B. | semiconductor & TTL |
| C. | mos technology & CMOS technology |
| D. | none of the mentioned |
| Answer» B. semiconductor & TTL | |
| 416. |
A power BJT is used as a power control switch by biasing it in the cut off region (off state) or in the saturation region (on state). In the on state |
| A. | both the base-emitter & base-collector junctions are forward biased |
| B. | the base-emitter junction is reverse biased, and the base collector junction is forward biased |
| C. | the base-emitter junction is forward biased, and the base collector junction is reversed biased |
| D. | both the base-collector & the base-emitter junctions are reversed biased |
| Answer» B. the base-emitter junction is reverse biased, and the base collector junction is forward biased | |
| 417. |
A power transistor is a _________ device. |
| A. | two terminal, bipolar, voltage controlled |
| B. | two terminal, unipolar, current controlled |
| C. | three terminal, unipolar, voltage controlled |
| D. | three terminal, bipolar, current controlled |
| Answer» E. | |
| 418. |
A power transistor is a |
| A. | three layer, three junction device |
| B. | three layer, two junction device |
| C. | two layer, one junction device |
| D. | four layer, three junction device |
| Answer» C. two layer, one junction device | |
| 419. |
Which of the following devices does not belong to the transistor family? |
| A. | IGBT |
| B. | MOSFET |
| C. | GTO |
| D. | BJT |
| Answer» D. BJT | |
| 420. |
Zener diodes allow a current to flow in the reverse direction, when the |
| A. | voltage reaches above a certain value |
| B. | temperature reaches above a certain value |
| C. | current always flows in the reverse direction only |
| D. | current cannot flow in the reverse direction |
| Answer» B. temperature reaches above a certain value | |
| 421. |
In a certain power electronics application, it is required that the voltage at the load terminals is to be kept within a certain range of voltages only. Among the device listed below, which would be the most ideal choice for this application? |
| A. | P-n junction diode |
| B. | Schottky diode |
| C. | Zener diode |
| D. | Fast recover diode |
| Answer» D. Fast recover diode | |
| 422. |
As compared to a p-n junction device of equal rating, the Schottky diode has |
| A. | lower reverse voltage rating |
| B. | lower reverse leakage current |
| C. | higher Switching time |
| D. | higher cut-in voltage |
| Answer» B. lower reverse leakage current | |
| 423. |
In a Schottky diode, the aluminum metal acts as a __________ |
| A. | anode |
| B. | cathode |
| C. | cathode |
| D. | common terminal |
| Answer» B. cathode | |
| 424. |
Schottky diodes are also called as |
| A. | metal diode |
| B. | hot carrier diode |
| C. | signaling diode |
| D. | easy turn on diode |
| Answer» C. signaling diode | |
| 425. |
When reverse breakdown occurs in a diode |
| A. | voltage increases & current is constant |
| B. | voltage increases & current also increases |
| C. | both are constant |
| D. | voltage is constant & current increases |
| Answer» E. | |
| 426. |
Ideally the voltage drop across a conducting diode must be |
| A. | ∞ |
| B. | 0 |
| C. | higher than the forward biased voltage |
| D. | equal to the forward biased voltage |
| Answer» C. higher than the forward biased voltage | |
| 427. |
A Schottky diode can be switchd off much faster than an equivalent p-n junction diode due to its |
| A. | higher operating frequency |
| B. | no recombination of charges |
| C. | more compact structure |
| D. | None of the mentioned |
| Answer» C. more compact structure | |
| 428. |
A Schottky diode has __________ |
| A. | a gate terminal |
| B. | aluminum-silicon junction |
| C. | platinum gold junction |
| D. | germanium-Arsenide junction |
| Answer» C. platinum gold junction | |
| 429. |
As compared to a p-n junction diode(of the same rating), a Schottky diode has ___________ |
| A. | higher cut-in voltage |
| B. | lower reverse leakage current |
| C. | higher operating frequency |
| D. | higher switching time |
| Answer» D. higher switching time | |
| 430. |
In a Schottky diode, the silcon is usually |
| A. | N-type |
| B. | P-type |
| C. | un-doped semiconductor |
| D. | silicon is not used |
| Answer» B. P-type | |
| 431. |
Which of the following are/is the majority charge carriers in a Schottky diode? |
| A. | Holes |
| B. | Electrons |
| C. | Both holes & Electrons carry equal current |
| D. | None of the mentioned |
| Answer» C. Both holes & Electrons carry equal current | |
| 432. |
Which of the below mentioned statements is false regarding Schottky diodes? |
| A. | Schottky diodes have a Al-Silicon junction |
| B. | There is no storage of charges in a Schottky diode |
| C. | The majority charge carriers in a Schottky diode are holes |
| D. | Schottky diodes can be switched off faster than a p-n junction diode of the same rating |
| Answer» D. Schottky diodes can be switched off faster than a p-n junction diode of the same rating | |
| 433. |
Which of the following diodes uses a metal-semiconductor junction? |
| A. | General purpose diodes |
| B. | Fast recovery diodes |
| C. | Schottky diode |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 434. |
In order to reduce the reverse recovery time of the diodes, __________ is carried out. |
| A. | shortening of the length of the device |
| B. | platinum & gold doping |
| C. | antimony doping |
| D. | adding an extra silicon layer |
| Answer» C. antimony doping | |
| 435. |
A power diode with small softness factor (S-factor) has |
| A. | small oscillatory over voltages |
| B. | large oscillatory over voltages |
| C. | large peak reverse current |
| D. | small peak reverse current |
| Answer» C. large peak reverse current | |
| 436. |
A diode is said to be forward biased when the |
| A. | cathode is positive with respect to the anode |
| B. | anode is positive with respect to the cathode |
| C. | anode is negative with respect to the anode |
| D. | both cathode & anode are positive |
| Answer» C. anode is negative with respect to the anode | |
| 437. |
A diode is said to be reversed biased when the |
| A. | cathode is positive with respect to the anode |
| B. | anode is positive with respect to the cathode |
| C. | cathode is negative with respect to the anode |
| D. | both cathode & anode are negative |
| Answer» B. anode is positive with respect to the cathode | |
| 438. |
Which of the following is true in case of a power diode with R load? |
| A. | I grows almost linearly with V |
| B. | I decays almost linearly with V |
| C. | I is independent of V |
| D. | I initial grows than decays |
| Answer» B. I decays almost linearly with V | |
| 439. |
The V-I Characteristics of the diode lie in the |
| A. | 1st & 2nd quadrant |
| B. | 1st & 3rd quadrant |
| C. | 1st & 4th quadrant |
| D. | Only in the 1st quadrant |
| Answer» C. 1st & 4th quadrant | |
| 440. |
Power diode is __________ |
| A. | a three terminal semiconductor device |
| B. | a two terminal semiconductor device |
| C. | a four terminal semiconductor device |
| D. | a three terminal analog device |
| Answer» C. a four terminal semiconductor device | |
| 441. |
To make a signal diode suitable for high current & high voltage carrying applications with minimum losses, ________ |
| A. | a lightly doped n layer is grown between the two p & n layers |
| B. | a heavily doped n layer is grown between the two p & n layers |
| C. | a lightly doped p layer is grown between the two p & n layers |
| D. | a heavily doped p layer is grown between the two p & n layers |
| Answer» B. a heavily doped n layer is grown between the two p & n layers | |
| 442. |
An ideal power diode must have |
| A. | low forward current carrying capacity |
| B. | large reverse breakdown voltage |
| C. | high ohmic junction resistance |
| D. | high reverse recovery time |
| Answer» C. high ohmic junction resistance | |
| 443. |
Which of the following is true in case of a forward biased p-n junction diode? |
| A. | The positive terminal of the battery sucks electrons from the p-region |
| B. | The positive terminal of the battery injects electrons into the p-region |
| C. | The negative terminal of the battery sucks electrons from the p-region |
| D. | None of the above mentioned statements are true |
| Answer» B. The positive terminal of the battery injects electrons into the p-region | |
| 444. |
Which of the following is true in case of an unbiased p-n junction diode? |
| A. | Diffusion does not take place |
| B. | Diffusion of electrons & holes goes on infinitely |
| C. | There is zero electrical potential across the junctions |
| D. | Charges establish an electric field across the junctions |
| Answer» E. | |
| 445. |
When a physical contact between a p-region & n-region is established which of the following is most likely to take place? |
| A. | Electrons from N-region diffuse to P-region |
| B. | Holes from P-region diffuse to N-region |
| C. | Both of the above mentioned statements are true |
| D. | Nothing will happen |
| Answer» D. Nothing will happen | |
| 446. |
In the p & n regions of the p-n junction the _________ & the ___________ are the minority charge carriers respectively. |
| A. | holes, holes |
| B. | electrons, electrons |
| C. | holes, electrons |
| D. | electrons, holes |
| Answer» E. | |
| 447. |
Which of the below mentioned statements is false regarding a p-n junction diode? |
| A. | Diode are uncontrolled devices |
| B. | Diodes are rectifying devices |
| C. | Diodes are unidirectional devices |
| D. | Diodes have three terminals |
| Answer» E. | |
| 448. |
The n-region has a greater concentration of _________ as compared to the p-region in a P-N junction diode.a |
| A. | holes |
| B. | electrons |
| C. | both holes & electrons |
| D. | phonons |
| Answer» C. both holes & electrons | |
| 449. |
In the p & n regions of the p-n junction the _________ & the ___________ are the majority charge carriers respectively. |
| A. | holes, holes |
| B. | electrons, electrons |
| C. | holes, electrons |
| D. | holes, electrons |
| Answer» D. holes, electrons | |
| 450. |
A p-type semiconductor material is doped with ____________ impurities whereas a n-type semiconductor material is doped with __________ impurities |
| A. | acceptor, donor |
| B. | acceptor, acceptor |
| C. | donor, donor |
| D. | donor, acceptor |
| Answer» B. acceptor, acceptor | |