MCQOPTIONS
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MCQOPTIONS
This section includes 869 Mcqs, each offering curated multiple-choice questions to sharpen your BITSAT knowledge and support exam preparation. Choose a topic below to get started.
| 401. |
In energy band diagram of p type semiconductor the acceptor energy level is |
| A. | in valence band |
| B. | in conduction band |
| C. | slightly above valence band |
| D. | slightly below conduction band |
| Answer» D. slightly below conduction band | |
| 402. |
Electrons can be emitted from a metal surface due to high electric field. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 403. |
In which mode of BJT operation are both junctions forward biased? |
| A. | Active |
| B. | Saturation |
| C. | Cut off |
| D. | Reverse active |
| Answer» C. Cut off | |
| 404. |
A metal loses electrons at room temperature. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |
| 405. |
The number of protons in a silicon atom is |
| A. | 32 |
| B. | 28 |
| C. | 14 |
| D. | 4 |
| Answer» D. 4 | |
| 406. |
When a p-n junction is forward biased. The width of depletion layer decreases.π |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 407. |
Magnetic recording tape is most commonly made from |
| A. | small particles of iron |
| B. | silicon iron |
| C. | ferric-oxide |
| D. | silver nitrate |
| Answer» D. silver nitrate | |
| 408. |
The minimum charge carried by an ion is |
| A. | zero |
| B. | equal to the change of an electron |
| C. | equal to the change of a pair of electrons |
| D. | equal to the change of electrons left in the atom |
| Answer» C. equal to the change of a pair of electrons | |
| 409. |
In which mode of BJT operation are both junctions reverse biased? |
| A. | Active |
| B. | Saturation |
| C. | Cut off |
| D. | Reverse active |
| Answer» D. Reverse active | |
| 410. |
The v-i characteristics of a diode may be linear or non linear. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |
| 411. |
When a diode is forward biased, the diode current is |
| A. | high |
| B. | low |
| C. | zero |
| D. | low or zero |
| Answer» B. low | |
| 412. |
The derating factor for a BJT transistor is about |
| A. | 0.5 mW/°C |
| B. | 2.5 mW/°C |
| C. | 10 mW/°C |
| D. | 25 mW/°C |
| Answer» C. 10 mW/°C | |
| 413. |
In degenerate p type semiconductor material, the Fermi level, |
| A. | is in the valence band |
| B. | is in conduction band |
| C. | is at the centre in between valence and conduction bands |
| D. | is very near conduction band |
| Answer» B. is in conduction band | |
| 414. |
Gel is |
| A. | a polymer having side groups distributed randomly along a vinly polymer chain |
| B. | a polymer having secondary chains branching from the main molecular chain |
| C. | a solid frame work of colloidal particles linked together and containing a fluid |
| D. | a polymer in which the repeating unit of each molecule has vinyl group |
| Answer» D. a polymer in which the repeating unit of each molecule has vinyl group | |
| 415. |
A potential of 7 V is applied to a silicon diode. A resistance of 1 K ohm is also in series with the diode. The current is |
| A. | 7 mA |
| B. | 6.3 mA |
| C. | 0.7 mA |
| D. | 0 |
| Answer» C. 0.7 mA | |
| 416. |
Electric breakdown strength of a material depends on its |
| A. | composition |
| B. | moisture content |
| C. | thickness |
| D. | all of the above |
| Answer» E. | |
| 417. |
Consider the following statements:1. Acceptor level lies close the valence band.2. Donor level lies close to the valence band.3. n type semiconductor behaves as an insulator at 0 K.4. p type semiconductor behaves as an insulator at 0 K. Of these statements: |
| A. | 2 and 3 are correct |
| B. | 1 and 3 are correct |
| C. | 1 and 4 are correct |
| D. | 3 and 4 are correct |
| Answer» D. 3 and 4 are correct | |
| 418. |
Avalanche beakdown is primarily dependent on the phenomenon of |
| A. | doping |
| B. | collision |
| C. | recombination |
| D. | ionization |
| Answer» C. recombination | |
| 419. |
Consider the following statement associated with bipolar junction transistor and JFET 1. The former has higher input impedance than the later2. The former has higher frequency stability than the later3. The later has lower noise figure than the former4. The later has higher power rating than the formerOf these statements |
| A. | 1 and 2 are correct |
| B. | 2 and 3 are correct |
| C. | 3 and 4 are correct |
| D. | 1 and 4 are correct |
| Answer» C. 3 and 4 are correct | |
| 420. |
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 | |
| 421. |
The range of life time carriers (electrons and holes) is |
| A. | 1 μs to 100 μs |
| B. | 1 nano sec to 1 μs |
| C. | 1 nano sec to hundreds of μs |
| D. | none of the above |
| Answer» D. none of the above | |
| 422. |
Which of the following element does not have three valence electrons? |
| A. | Boron |
| B. | Aluminium |
| C. | Gallium |
| D. | Phosphorus |
| Answer» E. | |
| 423. |
The cut in voltage |
| A. | is the same for silicon and germanium diodes |
| B. | is a forward voltage |
| C. | is a reverse voltage |
| D. | is a forward voltage below which the current is very small |
| Answer» E. | |
| 424. |
In modern MOSFETs, the material used for the gate is |
| A. | high purity silicon |
| B. | high purity silica |
| C. | heavily doped polycrystalline silicon |
| D. | epitaxial grown silicon |
| Answer» D. epitaxial grown silicon | |
| 425. |
The number of doped regions in a bipolar junction transistor is |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 426. |
Assertion (A): When VDS is more than rated value the drain current in a JFET is very high.Reason (R): When VDS is more than rated value, avalanche breakdown occurs. |
| 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 | |
| 427. |
Metals approach superconductivity conditions |
| A. | near absolute zero temperature |
| B. | near critical temperature |
| C. | at triple point |
| D. | under the conditions of high temperature and pressure |
| Answer» B. near critical temperature | |
| 428. |
Which of the following element has four valence electrons? |
| A. | Silicon |
| B. | Germanium |
| C. | Both (a) and (b) above |
| D. | None of the above |
| Answer» D. None of the above | |
| 429. |
The mean free path of conduction electrons in copper is about 4 x 10¯⁸ m. For a copper block, find the electric field which can give, on an average, 1 eV energy to a conduction electron |
| A. | 2.62 x 10⁷ V/m |
| B. | 2.64 x 10⁷ V/m |
| C. | 2.5 x 10⁷ V/m |
| D. | 2.58 x 10⁷ V/m |
| Answer» D. 2.58 x 10⁷ V/m | |
| 430. |
Choose proper substitutes for x and y to make the following statement correct.Tunnel diode, Avalanche photodiode are operated in x bias and y bias respectively. |
| A. | x : Reverse, y : Reverse |
| B. | x : Reverse, y : forward |
| C. | x : Forward, y : Reverse |
| D. | x : forward, y : forward |
| Answer» D. x : forward, y : forward | |
| 431. |
Silicon diodes have __________ reverse resistance than germanium diodes. |
| A. | a much smaller |
| B. | a much larger |
| C. | an infinite |
| D. | a negligible |
| Answer» C. an infinite | |
| 432. |
For a BJT, under the saturation condition, |
| A. | IC = βIB |
| B. | IC = αIB |
| C. | IC is independent of all other parameters |
| D. | IC < βIB |
| Answer» E. | |
| 433. |
Assertion (A): In design of circuit using BJT, a derating factor is used.Reason (R): As the ambient temperature increases, heat dissipation becomes slower. |
| 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 | |
| 434. |
The forbidden energy gap for germanium is |
| A. | 0.12 eV |
| B. | 0.32 eV |
| C. | 0.72 eV |
| D. | 0.92 eV |
| Answer» D. 0.92 eV | |
| 435. |
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. | |
| 436. |
The intrinsic carrier concentration of silicon sample at 300 K is 1.5 x 1016/m³. If after doping, the number of majority carriers is 5 x 1020/m³. The minority carrier density is |
| A. | 4.5 x 1011/m³ |
| B. | 3.33 x 104/m³ |
| C. | 5 x 1020/m³ |
| D. | 3 x 10-5/m³ |
| Answer» B. 3.33 x 104/m³ | |
| 437. |
The reverse saturation current of a diode does not depend on temperature. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |
| 438. |
An amplifier with resistive -ve feedback has two left poles in its open loop transfer function. The amplifier |
| A. | will always be unstable at high frequencies |
| B. | will be stable for all frequencies |
| C. | may be unstable, depending on the feedback factor |
| D. | will oscillate at low frequencies |
| Answer» C. may be unstable, depending on the feedback factor | |
| 439. |
SCR can be turned on by 1. applying anode voltage at a sufficient fast rate2. applying sufficiently large anode voltage3. increasing the temperature of SCR to a sufficiently4. applying sufficiently large gate current |
| A. | 1, 2, 4 only |
| B. | 4 only |
| C. | 1, 2, 3, 4 |
| D. | none |
| Answer» D. none | |
| 440. |
In a photo transistor the photocurrent is |
| A. | emitter base junction |
| B. | collector base junction |
| C. | collector |
| D. | either (a) or (b) |
| Answer» C. collector | |
| 441. |
In which of the following is the width of junction barrier very small? |
| A. | Tunnel diode |
| B. | Photo diode |
| C. | PIN diode |
| D. | Schottky diode |
| Answer» E. | |
| 442. |
The ratio of impurity atoms to intrinsic semiconductor atoms in an extrinsic semiconductor is about. |
| A. | 1 : 10 |
| B. | 1 : 1000 |
| C. | 1 : 100000 |
| D. | 1 : 10⁸ |
| Answer» E. | |
| 443. |
The mass of an electron is nearly |
| A. | 9.1 x 10¯²⁷ kg |
| B. | 9.1 x 10¯²⁹ kg |
| C. | 9.1 x 10¯³¹ kg |
| D. | 9.1 x 10¯³⁵ kg |
| Answer» D. 9.1 x 10¯³⁵ kg | |
| 444. |
In a reverse biased p-n junction, the reverse bias is 4V. The junction capacitance is about |
| A. | 0.1 F |
| B. | 4 μF |
| C. | 10 nF |
| D. | 20 pF |
| Answer» E. | |
| 445. |
An air gap provided in the iron core of an inductor prevents |
| A. | flux leakage |
| B. | hysteresis loss |
| C. | core saturation |
| D. | heat generation |
| Answer» D. heat generation | |
| 446. |
A particular green LED emits light of wavelength 5490, Å, the energy bandgap of the semiconductor material used there is .. h = 6.6 x 10¯³⁴ J sec. |
| A. | 2.26 eV |
| B. | 1.98 eV |
| C. | 1.17 eV |
| D. | 0.74 eV |
| Answer» B. 1.98 eV | |
| 447. |
Of the various capacitances associated with a junction transistor the gain bandwidth product is affected to maximum extend by |
| A. | base collector parasitic capacitor |
| B. | base collector space charge layer capacitance |
| C. | base emitter space charge layer capacitance |
| D. | base emitter diffusion capacitance |
| Answer» E. | |
| 448. |
If 1 kVA transformer is used for all of the following rectifiers, the d.c. power availability will be least in case of |
| A. | half wave rectifier |
| B. | full wave rectifier |
| C. | bridge rectifier |
| D. | three phase full wave rectifier |
| Answer» E. | |
| 449. |
No load d.c. output will be least in case of |
| A. | half wave rectifier |
| B. | full wave rectifier |
| C. | bridge rectifier |
| D. | three phase full wave rectifier |
| Answer» B. full wave rectifier | |
| 450. |
For a P-N junction diode, the current in reverse bias may be |
| A. | few amperes |
| B. | between 0.5 A and 1 A |
| C. | few milliamperes |
| D. | few micro or nanoamperes |
| Answer» E. | |