MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 1017 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics & Communication Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 351. |
A differential amplifier is invariably used in the I/P stage of all OP-amps. This is done basically to produce the OP-amp with a very high. |
| A. | CMRR |
| B. | bandwidth |
| C. | slew rate |
| D. | open-loop gain |
| Answer» E. | |
| 352. |
During induction heating of metals which of the following is abnormally high? |
| A. | Frequency |
| B. | Voltage |
| C. | Current |
| D. | Power factor |
| Answer» B. Voltage | |
| 353. |
In standard TTL, the 'totem pole' stage refers to |
| A. | the multi-emitter I/P stage |
| B. | phase splitter |
| C. | the O/P buffer |
| D. | open collector O/P stage |
| Answer» D. open collector O/P stage | |
| 354. |
In the schematic representation of bipolar junction transistor, the direction of arrow shows the direction of flow of |
| A. | holes |
| B. | electrons |
| C. | holes in pnp and electrons in npn |
| D. | electrons in pnp and holes in npn |
| Answer» B. electrons | |
| 355. |
Which of the following insulating material is restricted to temperatures below 100°C? |
| A. | Teflon |
| B. | Polythene |
| C. | reduces gain |
| D. | increase frequency and phase distortion |
| Answer» E. | |
| 356. |
An n channel depletion type MOSFET has |
| A. | highly doped p substrate and lightly doped n source and drain |
| B. | lightly doped n substrate and highly doped n source and drain |
| C. | VDS = 22 V |
| D. | VDS more than 22 V |
| Answer» B. lightly doped n substrate and highly doped n source and drain | |
| 357. |
In a semi-conductor diode, the barrier offers opposition to |
| A. | holes in P-region only |
| B. | free electrons in N-region only |
| C. | majority carriers in both regions |
| D. | majority as well as minority carriers in both regions |
| Answer» D. majority as well as minority carriers in both regions | |
| 358. |
The mean life time of the minority carriers is in the range of a few |
| A. | seconds |
| B. | milli seconds |
| C. | micro seconds |
| D. | nano seconds |
| Answer» E. | |
| 359. |
In a bipolar junction transistor the base region is made very thin so that |
| A. | recombination in base region is minimum |
| B. | electric field gradient in base is high |
| C. | base can be easily fabricated |
| D. | base can be easily biased |
| Answer» B. electric field gradient in base is high | |
| 360. |
A JFET |
| A. | is current controlled device |
| B. | has low input resistance |
| C. | has high gate current |
| D. | is a voltage controlled device |
| Answer» E. | |
| 361. |
In a CE bipolar transistor operating in active region, collector current is independent of |
| A. | VCE |
| B. | IB |
| C. | both VCE and IB |
| D. | none of the above |
| Answer» B. IB | |
| 362. |
A Schottky diode clamp is used along with a switching BJT for |
| A. | reducing the power |
| B. | reducing the switching time dissipation |
| C. | increasing the value of β |
| D. | reducing the base current |
| Answer» C. increasing the value of Œ≤ | |
| 363. |
A voltage of 9 V is applied in forward direction to a semiconductor diode in series with a load resistance of 1000 Ω. The voltage across the load resistance is zero. It indicates that |
| A. | diode is short circuited |
| B. | diode is open circuited |
| C. | resistor is open circuited |
| D. | diode is either o.c or s.c |
| Answer» C. resistor is open circuited | |
| 364. |
Which one of the following circuits is most suitable as an oscillator at a frequency of 100Hz? |
| A. | Hartley oscillator |
| B. | Colpitts oscillator |
| C. | Crystal oscillator |
| D. | Twin-T oscillator |
| Answer» B. Colpitts oscillator | |
| 365. |
In a piezoelectric crystal, application of a mechanical stress would produce |
| A. | electric polarization in the crystal |
| B. | shift in the Fermi level |
| C. | is always equal to 1 |
| D. | is less than 1 but more than 0.9 |
| Answer» D. is less than 1 but more than 0.9 | |
| 366. |
Eg is the band gap, A is pre-factor, k is Boltzmann constant? Which one of the following is the remaining grade of paper used in paper capacitor, besides the other two grade of paper-low and extra low loss? |
| A. | Strong dielectric |
| B. | Regular |
| C. | Rough |
| D. | High loss |
| Answer» C. Rough | |
| 367. |
The reverse breakdown voltage of a diode depends on the extent of doping. |
| A. | 1 |
| B. | |
| C. | mobility of charge carriers |
| D. | type of the conductivity and concentration of charge carriers |
| Answer» B. | |
| 368. |
In energy band diagram of n type semiconductor, the donor energy level is |
| A. | in valence band |
| B. | in conduction band |
| C. | slightly above valence band |
| D. | slightly below conduction band |
| Answer» E. | |
| 369. |
From the given circuit below, we can conclude that. |
| A. | BJT is pnp |
| B. | BJT is npn |
| C. | transistor is faulty |
| D. | not possible to determined |
| Answer» D. not possible to determined | |
| 370. |
The depletion layer consists of immobile ions. |
| A. | 1 |
| B. | |
| C. | only an ohmic region |
| D. | only a saturation region |
| Answer» B. | |
| 371. |
An inductor filter has a ripple that __________ with load resistance and consequently is used only with relatively __________ load currents. |
| A. | decreases, low |
| B. | decreases, high |
| C. | increases, low |
| D. | increases, high |
| Answer» E. | |
| 372. |
In intrinsic semiconductor, the fermi level |
| A. | lies at the centre of forbidden energy gap |
| B. | is near the conduction band |
| C. | is near the valence band |
| D. | may be anywhere in the forbidden energy gap |
| Answer» B. is near the conduction band | |
| 373. |
If E is electric field intensity, the current density due to field emission is proportional to |
| A. | E |
| B. | E2 |
| C. | E2.5 |
| D. | E3/2 |
| Answer» C. E2.5 | |
| 374. |
In a JFET the width of channel is controlled by |
| A. | source current |
| B. | all of the above |
| C. | Ohms |
| D. | Ohms/°C |
| Answer» B. all of the above | |
| 375. |
For a MOS capacitor fabricated on a P-type semiconductor, strong inversion occurs when |
| A. | surface potential is equal to Fermi potential |
| B. | surface Potential is greater than Fermi potential |
| C. | surface potential is - ve and equal to Fermi potential in magnitude |
| D. | surface potential is + ve and equal to twice the Fermi potential |
| Answer» E. | |
| 376. |
An electron in the conduction band |
| A. | has higher energy than the electron in the valence band |
| B. | has lower energy than the electron in the valence band |
| C. | loses its charge easily |
| D. | jumps to the top of the crystal |
| Answer» B. has lower energy than the electron in the valence band | |
| 377. |
The number of valence electrons in a donor atom is |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 5 |
| Answer» E. | |
| 378. |
Secondary emission occurs in |
| A. | diode |
| B. | triode |
| C. | tetrode |
| D. | pentode |
| Answer» D. pentode | |
| 379. |
The depletion layer width of Junction |
| A. | decreases with light doping |
| B. | is independent of applied voltage |
| C. | is increased under reverse bias |
| D. | increases with heavy doping |
| Answer» D. increases with heavy doping | |
| 380. |
The number of doped regions in a bipolar junction transistor is |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 381. |
When atoms are held together by the sharing of valence electrons |
| A. | each atom becomes free to move |
| B. | neutrons start shifting |
| C. | they form a covalent bond |
| D. | some of the electrons are lost |
| Answer» D. some of the electrons are lost | |
| 382. |
Which of the following element does not have three valence electrons? |
| A. | Boron |
| B. | Aluminium |
| C. | Gallium |
| D. | Phosphorus |
| Answer» E. | |
| 383. |
Wienbridge oscillator uses |
| A. | #NAME? |
| B. | #NAME? |
| C. | both +ve, -ve feedback |
| D. | feedback is not required |
| Answer» D. feedback is not required | |
| 384. |
The cut in voltage of a diode is nearly equal to |
| A. | applied forward voltage |
| B. | applied reverse voltage |
| C. | barrier potential |
| D. | none of the above |
| Answer» D. none of the above | |
| 385. |
Assertion (A): The capacitance of a reverse biased pin diode is lower than that of reverse biased p-n diode. Reason (R): A PIN diode has an intrinsic layer between p and n regions. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not a correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» B. Both A and R are true but R is not a correct explanation of A | |
| 386. |
In all metals |
| A. | conductivity decreases with increase in temperature |
| B. | current flow by electrons as well as by holes |
| C. | resistivity decreases with increase in temperature |
| D. | the gap between valence and conduction bands is small |
| Answer» B. current flow by electrons as well as by holes | |
| 387. |
Which of the following expressions may be used to correctly describe the temperature (T) variation of the intrinsic carrier density (ni) of a semiconductor? |
| A. | ni(T) = (A/T) exp (- E8/kT2) |
| B. | ni(T) = A (- E8/2kT)10 |
| C. | ni(T) = A exp (- E8/2kT2) |
| D. | ni(T) = AT3/2 exp (-E8/2kT) |
| Answer» E. | |
| 388. |
Assertion (A): In intrinsic semiconductors, the charge concentration increases with temperature. Reason (R): At higher temperatures, the forbidden energy gap in semiconductors is lower. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not a correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» B. Both A and R are true but R is not a correct explanation of A | |
| 389. |
In forward active region, the operation of a BJT |
| A. | emitter base junction is forward biased and base collector junction is reverse biased |
| B. | emitter base junction is reverse biased and base collector junction is reverse biased |
| C. | mobility of the carrier |
| D. | effective density of states in the conduction band |
| Answer» D. effective density of states in the conduction band | |
| 390. |
Assertion (A): Silicon is preferred over germanium in manufacture of semiconductor devices. Reason (R): Forbidden gap in silicon is more than that in germanium. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not a correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» B. Both A and R are true but R is not a correct explanation of A | |
| 391. |
A photo diode is |
| A. | forward biased |
| B. | reverse biased |
| C. | either forward or reverse biased |
| D. | unbiased |
| Answer» C. either forward or reverse biased | |
| 392. |
If both the emitter base and the collector base junctions of a bipolar transistor are forward biased, the transistor is in the |
| A. | active region |
| B. | saturated region |
| C. | cut off region |
| D. | inverse mode |
| Answer» C. cut off region | |
| 393. |
The effect of current shunt feedback in an amplifier is to |
| A. | increase the I/P resistance and decrease the O/P resistance |
| B. | increase both I/P and O/P resistance |
| C. | decrease both I/P and O/P resistance |
| D. | decrease the I/P resistance and increase O/P resistance |
| Answer» E. | |
| 394. |
Discrete transistors T1 and T2 having maximum collector current rating of 0.75 amp are connected in parallel as shown in the figure, this combination is treated as a single transistor to carry a total current of 1 ampere, when biased with self bias circuit. When the circuit is switched on, T1 draws 0.55 amps and T2 draws 0.45 amps. If the supply is kept on continuously, ultimately it is very likely that |
| A. | Both T1, and T2 get damaged |
| B. | Both T1, and T2 will be safe. |
| C. | T1 Will get damaged and T2 will be safe |
| D. | T2 will get damaged and T1, will be safe. |
| Answer» D. T2 will get damaged and T1, will be safe. | |
| 395. |
If the drift velocity of holes under a field gradient of 100 V/m is 5m/sec. Their mobility is |
| A. | 0.05 |
| B. | 0.5 |
| C. | 50 |
| D. | 500 |
| Answer» B. 0.5 | |
| 396. |
Transition capacitance is associated with __________ and depletion capacitance is associated with __________ diodes. |
| A. | reverse bias and forward bias |
| B. | forward bias and reverse bias |
| C. | reverse bias and reverse bias |
| D. | forward bias and forward bias |
| Answer» D. forward bias and forward bias | |
| 397. |
In an ideal junction transistor the impurity concentration in emitter (E ), base (B) and collector (C) is such that |
| A. | E > B > C |
| B. | B > C > E |
| C. | C > E > B |
| D. | C = E = B |
| Answer» B. B > C > E | |
| 398. |
An n type silicon bar 0.1 cm long and 100 μm2 in cross-sectional area has a majority carrier concentration of 5 x 1020/m3 and the carrier mobility is 0.13 m0/V-s at 300k. If the charge of an electron is 1.6 x 10-19 coulomb, then the resistance of the bar is |
| A. | 106 ohm |
| B. | 104 ohm |
| C. | 10-1 ohm |
| D. | 10-4 ohm |
| Answer» D. 10-4 ohm | |
| 399. |
The number of protons in a silicon atom is |
| A. | 32 |
| B. | 28 |
| C. | 14 |
| D. | 4 |
| Answer» D. 4 | |
| 400. |
Resistivity is a property of a semiconductor that depends on |
| A. | the atomic weight of the semiconductor |
| B. | the atomic number of the semiconductor |
| C. | the atomic nature of the semiconductor |
| D. | the shape of the semiconductor |
| Answer» D. the shape of the semiconductor | |