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.
| 351. |
Ferrites are |
| A. | hard materials |
| B. | brittle materials |
| C. | not easily machinable |
| D. | materials with all above properties |
| Answer» E. | |
| 352. |
The reverse saturation current in a semiconductor diode consists of |
| A. | avalanche current |
| B. | zener current |
| C. | minority carrier current |
| D. | minority carrier current and surface leakage current |
| Answer» E. | |
| 353. |
As the temperature of an intrinsic semiconductor material is increased |
| A. | protons get excited |
| B. | neutrons acquire charge |
| C. | energy of the atom is increased |
| D. | additional holes are created in the conduction band |
| Answer» D. additional holes are created in the conduction band | |
| 354. |
Materials in order of decreasing electrical conductivity are |
| A. | aluminium, silver, gold, copper |
| B. | gold, silver, copper, aluminium |
| C. | copper, silver, gold, aluminium |
| D. | silver, copper, gold, aluminium |
| Answer» E. | |
| 355. |
Which of the following elements act as donor impurities? 1. Gold2. Phosphorus3. Boron4. Antimony5. Arsenic6. Indium Select the answer using the following codes : |
| A. | 1, 2 and 3 |
| B. | 1, 2, 4, and 6 |
| C. | 3, 4, 5 and 6 |
| D. | 2, 4 and 5 |
| Answer» E. | |
| 356. |
The carrier mobility in a semiconductor is 0.4 m²/Vs. Its diffusion constant at 300k will be (in m²/s). |
| A. | 0.43 |
| B. | 0.16 |
| C. | 0.04 |
| D. | 0.01 |
| Answer» C. 0.04 | |
| 357. |
For generating 1 MHz frequency signal, the most suitable circuit is |
| A. | phase shift oscillator |
| B. | weinbridge oscillator |
| C. | colpitt's oscillator |
| D. | clapp oscillator |
| Answer» D. clapp oscillator | |
| 358. |
The thermionic emission current is given by |
| A. | Fermi-Dirac distribution |
| B. | Maxwell's equation |
| C. | Richardson Dushman equation |
| D. | Langmuir Child law |
| Answer» D. Langmuir Child law | |
| 359. |
Assertion (A): A decrease in temperature increases the reverse saturation current in a p-n diode.Reason (R): When a diode is reverse biased surface leakage current flows. |
| 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» E. | |
| 360. |
An increase in junction temperature of a semiconductor diode |
| A. | causes a small increase in reverse saturation current |
| B. | causes a large increase in reverse saturation current |
| C. | does not affect reverse saturation current |
| D. | may cause an increase or decrease in reverse saturation current depending on rating of diode |
| Answer» C. does not affect reverse saturation current | |
| 361. |
Assertion (A): In Hall effect the O.C. transverse voltage developed by a current carrying semiconductor with a steady magnetic field perpendicular to the current direction has opposite signs for n and p semiconductors.Reason (R): The magnetic field pushes both holes and electrons in the same direction. |
| 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 | |
| 362. |
If an electron move through a potential difference of 500 V, the energy possesses by it will be |
| A. | 500 ergs |
| B. | 500 joules |
| C. | 500 eV |
| D. | 500 mV |
| Answer» D. 500 mV | |
| 363. |
In a p-n-p transistor the main current carriers and the mechanism of flow respectively are |
| A. | electrons, drift |
| B. | holes, drift |
| C. | holes, diffusion |
| D. | electrons, diffusion |
| Answer» D. electrons, diffusion | |
| 364. |
In a bipolar transistor, emitter efficiency is about |
| A. | 0.99 |
| B. | 0.9 |
| C. | 0.8 |
| D. | 0.7 |
| Answer» B. 0.9 | |
| 365. |
The function off an oxide layer in an IC device is to 1. mask against diffusion or ion implantation2. insulate the surface electrically3. increase the melting point of Si4. produce a chemically stable protective layer |
| A. | 1, 2, 3 |
| B. | 1, 3, 4 |
| C. | 2, 3, 4 |
| D. | 4, 1, 2 |
| Answer» E. | |
| 366. |
SCR turns of from conducting state to blocking state on |
| A. | reducing gate current |
| B. | reversing gate voltage |
| C. | reducing anode current below holding current value |
| D. | applying ac to the gate |
| Answer» D. applying ac to the gate | |
| 367. |
An insulator will conduct when the |
| A. | voltage applied is more than the breakdown voltage |
| B. | temperature is raised to very high level |
| C. | either (a) or (b) above |
| D. | none of the above |
| Answer» D. none of the above | |
| 368. |
EG for silicon is 1.12 eV and that for germanium is 0.72 eV. Therefore it can be concluded that |
| A. | more number of electron-hole pairs will be generated in silicon than in germanium at room temperature |
| B. | less number of electron hole pairs will be generated in silicon than in germanium at room temperature |
| C. | equal number of electron-hole pairs will be generated in both at lower temperatures |
| D. | equal number of electron-hole pairs will be generated in both at higher temperatures |
| Answer» C. equal number of electron-hole pairs will be generated in both at lower temperatures | |
| 369. |
Zener diode is invariably used with |
| A. | forward bias |
| B. | reverse bias |
| C. | either (a) or (b) |
| D. | zero bias |
| Answer» C. either (a) or (b) | |
| 370. |
Assertion (A): The forward dynamic resistance of p-n diode varies inversely with current.Reason (R): The forward dynamic resistance of p-n diode varies with the operating voltage. |
| 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» C. A is true but R is false | |
| 371. |
Resistivity of metals is expressed in terms of |
| A. | μ ohm |
| B. | μ ohm/cm |
| C. | μ ohm-cm |
| D. | μ ohm-cm/°C |
| Answer» D. μ ohm-cm/°C | |
| 372. |
What happens when forward bias is applied to a junction diode? |
| A. | Majority carrier current is reduced to zero |
| B. | Minority carrier current is reduced to zero |
| C. | Potential barrier is increased |
| D. | Potential barrier is decreased |
| Answer» E. | |
| 373. |
In photoelectric emission the maximum kinetic energy of emitted electron is proportional to |
| A. | √f |
| B. | f |
| C. | f² |
| D. | f³ |
| Answer» C. f² | |
| 374. |
Which of the following is an active device? |
| A. | Transformer |
| B. | Silicon controlled rectifier |
| C. | Electric bulb |
| D. | Loudspeaker |
| Answer» C. Electric bulb | |
| 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 intrinsic semiconductor (intrinsic electron density = 10¹⁶ m¯³) is deped with donors to a level of 10²² m¯³. What is the hole density assuming all donors to be ionized? |
| A. | 10⁷ m¯³ |
| B. | 10⁸ m¯³ |
| C. | 10¹ᴼ m¯³ |
| D. | 10⁶ m¯³ |
| Answer» E. | |
| 377. |
A potential difference is developed across a current carrying metal strip when the strip is placed in a transverse magnetic field. The above effect is known as |
| A. | Fermi's effect |
| B. | Photo electric effect |
| C. | Joule's effect |
| D. | Hall's effect |
| Answer» E. | |
| 378. |
In common base connection, the output characteristics of a bipolar junction transistor is drawn between |
| A. | IC and VCB |
| B. | IC and VCE |
| C. | IE and VCB |
| D. | IE and VCE |
| Answer» B. IC and VCE | |
| 379. |
The reverse breakdown voltage of a diode depends on the extent of doping. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 380. |
Thermal runaway is not possible in FET, because as the temperature of FET increases. |
| A. | the mobility decreases |
| B. | the transconductance increases |
| C. | impedance of the source |
| D. | power dissipation in the chip |
| Answer» C. impedance of the source | |
| 381. |
Which of the following semiconductor has the highest melting point? |
| A. | Germanium |
| B. | Silicon |
| C. | Gallium arsenide |
| D. | Lead sulphide |
| Answer» E. | |
| 382. |
Which of the following statements regarding two transistor model of p-n-n-p device is correct? |
| A. | It explain only the turn on portion of the device characteristics |
| B. | It explain only the turn off portion of the device characteristics |
| C. | It explain only the negative region portion of the device characteristics |
| D. | It explain all the regions of the device characteristics |
| Answer» E. | |
| 383. |
Breakdown in dielectric may be |
| A. | electrical breakdown |
| B. | thermal breakdown |
| C. | electrochemical breakdown |
| D. | any of the above |
| Answer» E. | |
| 384. |
The atomic number of silicon is 14. It can be therefore concluded that |
| A. | a silicon atom contains 14 protons |
| B. | a silicon atom contains 14 neutrons |
| C. | a silicon atom contains 14 electrons |
| D. | all of the above |
| Answer» E. | |
| 385. |
Addition of a small amount of antimony to germanium will result in |
| A. | formation of P-type semiconductor |
| B. | more free electrons than holes in the semiconductor |
| C. | antimony concentrating on the edges of the crystals |
| D. | increased resistance |
| Answer» C. antimony concentrating on the edges of the crystals | |
| 386. |
The energy to cause thermionic emission is supplied by heating the cathode. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 387. |
The effective channel length of a MOSFET in saturation decreases with increase in |
| A. | gate voltage |
| B. | drain voltage |
| C. | source voltage |
| D. | body voltage |
| Answer» B. drain voltage | |
| 388. |
Photo electric emission can occur only if the frequency of light is more than threshold frequency. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 389. |
For most metals, Fermi level EF is less than |
| A. | 0.1 eV |
| B. | 2 eV |
| C. | 5 eV |
| D. | 10 eV |
| Answer» E. | |
| 390. |
In a specimen of n type semiconductor, the initial concentration of holes and electrons is pno and nno. When the specimen is subjected to radiation, the hole and electron concentration increase to pn and nn. Then |
| A. | pn - pno = nn - nno |
| B. | pn + pno = nn + nno |
| C. | pn - pno = nno + nno |
| D. | pn + pno = nn - pno |
| Answer» B. pn + pno = nn + nno | |
| 391. |
The holes diffuse from P-region to the N-region in a P-N junction diode because |
| A. | there is greater concentration of holes in the P-region as compared to N-region |
| B. | there is greater concentration of holes in the N-region as compared to P-region |
| C. | the free electrons in the N-region attract them |
| D. | potential difference facilities such transfer |
| Answer» B. there is greater concentration of holes in the N-region as compared to P-region | |
| 392. |
In a JFET avalanche breakdown occurs when VDS = 22 V and VGS = 0. If VGS = -1 V, the avalanche breakdown will occur at |
| A. | VDS = 22 V |
| B. | VDS more than 22 V |
| C. | VDS equal to or more than 22 V |
| D. | VDS less than 22 V |
| Answer» E. | |
| 393. |
When a reverse bias is applied to a p-n junction, the width of depletion layer. |
| A. | decreases |
| B. | increases |
| C. | remains the same |
| D. | may increase or decrease |
| Answer» C. remains the same | |
| 394. |
Resistivity of hard drawn copper is |
| A. | less than that of annealed copper |
| B. | more than that of annealed copper |
| C. | same as that of annealed copper |
| D. | decreasing when temperature increases |
| Answer» C. same as that of annealed copper | |
| 395. |
The word enhancement mode is associated with |
| A. | tunnel diode |
| B. | MOSFET |
| C. | JFET |
| D. | photo diode |
| Answer» C. JFET | |
| 396. |
In which device does the extent of light controls the conduction |
| A. | photovoltaic cell |
| B. | photo electric relay |
| C. | LED |
| D. | photo sensitive device |
| Answer» E. | |
| 397. |
A bistable multivibrator |
| A. | has no stable state |
| B. | has one stable state |
| C. | has two stable state |
| D. | none of the above |
| Answer» D. none of the above | |
| 398. |
In p type semiconductor, the hole concentration |
| A. | is nearly equal to density of acceptor atoms |
| B. | is much greater than density of acceptor atoms |
| C. | is much less than density of acceptor atoms |
| D. | may be equal to or more or less than density of acceptor atoms |
| Answer» B. is much greater than density of acceptor atoms | |
| 399. |
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 | |
| 400. |
Amplification of ultrasonic waves is possible in a piezoelectric semiconductor under applied electric field. The basic phenomenon involved is known as |
| A. | electrostriction |
| B. | acousto-optic interaction |
| C. | acousto-electric interaction |
| D. | stimulated Brillouin scattering |
| Answer» D. stimulated Brillouin scattering | |