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MCQOPTIONS
This section includes 657 Mcqs, each offering curated multiple-choice questions to sharpen your Testing Subject knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The rating of a transformer to deliver 100 watts of D.C. power to a load under half wave rectifier will be nearly |
| A. | 1 kVA |
| B. | 350 VA |
| C. | 175 VA |
| D. | 108 VA |
| Answer» C. 175 VA | |
| 2. |
The temperature of cathode is increased from 2500K to 2600K. The increase in thermionic emission current is about |
| A. | 0.1% |
| B. | 4% |
| C. | 50% |
| D. | 150% |
| Answer» E. | |
| 3. |
Consider the following statements about diamagnetic material and diamagnetism. The materials have negative magnetic susceptibility.At very low temperature diamagnetic materials. Which of the statements given above is/are correct? |
| A. | 1 only |
| B. | 2 only |
| C. | Both 1 and 2 |
| D. | neither 1 nor 2 |
| Answer» B. 2 only | |
| 4. |
In a photo emissive device and emission efficiency is increased by |
| A. | coating the cathode ray by an active materials |
| B. | coating the cathode by an insulating material |
| C. | heating the cathode |
| D. | cooling the anode |
| Answer» B. coating the cathode by an insulating material | |
| 5. |
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. | |
| 6. |
When a ferromagnetic substance is magnetised, there are small changes in its dimensions. This phenomenon is called |
| A. | hysteresis |
| B. | magnetostriction |
| C. | diamagnetism |
| D. | bipolar relaxation |
| Answer» C. diamagnetism | |
| 7. |
Gold is often diffused into silicon PN junction devices to |
| A. | increase the recombination rate |
| B. | reduce the recombination rate |
| C. | make silicon a direct gap semiconductor |
| D. | make silicon semimetal |
| Answer» D. make silicon semimetal | |
| 8. |
In the figure shows the circuits symbol of |
| A. | FET |
| B. | PMOSFET |
| C. | CMOSFET |
| D. | NMOSFET |
| Answer» E. | |
| 9. |
Assertion (A): FET is a unipolar device. Reason (R): BJT is bipolar device. |
| 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 | |
| 10. |
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 | |
| 11. |
Secondary emission occurs in |
| A. | diode |
| B. | triode |
| C. | tetrode |
| D. | pentode |
| Answer» D. pentode | |
| 12. |
Which quantity controls the effectiveness of LED in emitting light? |
| A. | Applied voltage |
| B. | Current |
| C. | Extent of doping |
| D. | Temperature |
| Answer» E. | |
| 13. |
Ferromagnetic materials exhibit |
| A. | a linear B-H behaviour |
| B. | a non-linear B-H behaviour |
| C. | an exponential B-H behaviour |
| D. | none of the above |
| Answer» C. an exponential B-H behaviour | |
| 14. |
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 | |
| 15. |
A doped semi-conductor is called |
| A. | impure semi-conductor |
| B. | dipole semi-conductor |
| C. | bipolar semi-conductor |
| D. | extrinsic semi-conductor |
| Answer» E. | |
| 16. |
The saturation current in a semi-conductor diode |
| A. | depends on forward voltage |
| B. | depends on reverse voltage |
| C. | is due to thermally generated minority carriers |
| D. | none of the above |
| Answer» D. none of the above | |
| 17. |
Photo electric emission can occur only if the frequency of light is more than threshold frequency. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 18. |
The first and the last critical frequency of an RC driving point impedance function must respectively by |
| A. | a zero and a pole |
| B. | a zero and a zero |
| C. | a pole and a pole |
| D. | a pole and a zero |
| Answer» B. a zero and a zero | |
| 19. |
The diffusion current is proportional to |
| A. | applied electric field |
| B. | concentration gradient of charge carrier |
| C. | square of the electric field |
| D. | cube of the applied electric field |
| Answer» C. square of the electric field | |
| 20. |
High purity copper is obtained by |
| A. | rolling casting |
| B. | casting |
| C. | electrolytic refining |
| D. | induction heating |
| Answer» D. induction heating | |
| 21. |
Figure represents a |
| A. | Varactor |
| B. | LED |
| C. | Zener diode |
| D. | Temperature dependent diode |
| Answer» D. Temperature dependent diode | |
| 22. |
The unit of thermal resistance of a semi-conductor device is |
| A. | Ohms |
| B. | Ohms/ C |
| C. | C/ohm |
| D. | C/watt |
| Answer» E. | |
| 23. |
In a JFET the width of channel is controlled by |
| A. | gate voltage |
| B. | drain current |
| C. | source current |
| D. | all of the above |
| Answer» B. drain current | |
| 24. |
Atomic number of germanium is |
| A. | 24 |
| B. | 28 |
| C. | 32 |
| D. | 36 |
| Answer» D. 36 | |
| 25. |
The resistivity of ferrites is |
| A. | very much lower than that of the ferromagnetic metals |
| B. | slightly lower than that of the ferromagnetic materials |
| C. | slightly higher than that of the ferromagnetic metals |
| D. | very much higher than that of the ferromagnetic metals |
| Answer» E. | |
| 26. |
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. | |
| 27. |
At any point on the v-i characteristics of a semiconductor diode, the slope of v-i characteristics is called |
| A. | resistance of diode |
| B. | conductance of diode |
| C. | incremental resistance of diode |
| D. | incremental conductance of diode |
| Answer» E. | |
| 28. |
In monostable multivibrator |
| A. | has no stable state |
| B. | has one stable state |
| C. | has two stable states |
| D. | switches automatically from one state to other state |
| Answer» C. has two stable states | |
| 29. |
Diffusion constants Dp, Dn mobility p, n and absolute temperature T are related as |
| A. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/37-42-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/37-42-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/37-42-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/37-42-4.png"> |
| Answer» B. <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/37-42-2.png"> | |
| 30. |
The probability giving distribution of electrons over a range of allowed energy levels is known as |
| A. | Maxwell's Distribution |
| B. | Fermi-Dirac Distribution |
| C. | Richardson Dushman Distribution |
| D. | none of the above |
| Answer» C. Richardson Dushman Distribution | |
| 31. |
Hall coefficient is reciprocal of charge density. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 32. |
The intrinsic resistivity of silicon at 300 K is about |
| A. | 1 Ω-cm |
| B. | 400 Ω-cm |
| C. | 10000 Ω-cm |
| D. | 230000 Ω-cm |
| Answer» E. | |
| 33. |
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. | |
| 34. |
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. | |
| 35. |
The v-i characteristic of an element is shown in below figure the element is |
| A. | non-linear, active, non-bilateral |
| B. | linear, active, non-bilateral |
| C. | non-linear, passive, non-bilateral |
| D. | non-linear, active, bilateral |
| Answer» E. | |
| 36. |
In which of the following does a negative resistance region exist in the v-i characteristics? |
| A. | PIN diode |
| B. | Schottky diode |
| C. | Tunnel diode |
| D. | Zener diode |
| Answer» D. Zener diode | |
| 37. |
Reluctivity is analogous to |
| A. | permeability |
| B. | conductivity |
| C. | resistivity |
| D. | retentivity |
| Answer» D. retentivity | |
| 38. |
If the conductivity of pure germanium is 1.54 siemens/metre, its resistivity in ohm-metre will be nearly |
| A. | 65 |
| B. | 6.5 |
| C. | 0.65 |
| D. | 0.065 |
| Answer» C. 0.65 | |
| 39. |
The v-i characteristics of a diode may be linear or non linear. |
| A. | True |
| B. | False |
| Answer» C. | |
| 40. |
The band gap of Si at room temperature is |
| A. | 1.3 eV |
| B. | 0.7 eV |
| C. | 1.1 eV |
| D. | 1.4 eV |
| Answer» D. 1.4 eV | |
| 41. |
Spot the odd one out |
| A. | aluminium |
| B. | silver |
| C. | porcelain |
| D. | copper |
| Answer» D. copper | |
| 42. |
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 | |
| 43. |
Figure represents a |
| A. | Tunnel diode |
| B. | PNP transistor |
| C. | Photo sensitive diode |
| D. | Photo emissive diode |
| Answer» B. PNP transistor | |
| 44. |
If the energy gap of a semiconductor is 1.1 eV, then it would be. |
| A. | opaque to the visible light |
| B. | transparent to the visible light |
| C. | transparent to the ultraviolet radiation |
| D. | opaque to the infrared radiation |
| Answer» B. transparent to the visible light | |
| 45. |
Under low level injection assumption, the infected minority carrier current for an extrinsic semiconductor is essentially the |
| A. | diffusion current |
| B. | drift current |
| C. | recombination current |
| D. | induced current |
| Answer» B. drift current | |
| 46. |
The addition of impurity in extrinsic semiconductor is about 1 part in 108 parts. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 47. |
As the reverse voltage is increased, the depletion layer |
| A. | becomes narrow |
| B. | widens |
| C. | remains the same |
| D. | reduce to zero |
| Answer» C. remains the same | |
| 48. |
The cascade amplifier is a multistage configuration of |
| A. | CC-CB |
| B. | CE-CB |
| C. | CB-CC |
| D. | CE-CC |
| Answer» C. CB-CC | |
| 49. |
The light output of LED varies as (current)n. The value of n is about |
| A. | 0.5 |
| B. | 1 |
| C. | 1.3 |
| D. | 2.1 |
| Answer» D. 2.1 | |
| 50. |
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 | |