MCQOPTIONS
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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.
| 751. |
Which impurity atom will give p type semiconductor when added to intrinsic semiconductor? |
| A. | Phosphorus |
| B. | Boron |
| C. | Arsenic |
| D. | Antimony |
| Answer» C. Arsenic | |
| 752. |
Which of the following devices has substrate? |
| A. | JFET |
| B. | Depletion Type MOSFET |
| C. | Enhancement type MOSFET |
| D. | Both (b) and (c) |
| Answer» E. | |
| 753. |
The primary function of a clamper circuit is to |
| A. | suppress variations in signal voltage |
| B. | raise +ve half cycle to the signal |
| C. | Lower -ve half cycle of the signal |
| D. | introduce a dc level into an a.c. signal |
| Answer» C. Lower -ve half cycle of the signal | |
| 754. |
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 | |
| 755. |
When a high voltage reference is required it is advantageous to use two or more zener diodes in series to allow |
| A. | higher voltage |
| B. | higher dissipation |
| C. | lower temperature coefficient |
| D. | all of the above |
| Answer» E. | |
| 756. |
An n channel JFET has IDS whose value is |
| A. | maximum for VGS = 0 and minimum for VGS negative and large |
| B. | minimum for VGS = 0 and maximum for VGS negative and large |
| C. | maximum for VGS = 0 and minimum for VGS positive and large |
| D. | minimum for VGS = 0 and maximum for VGS positive and large |
| Answer» B. minimum for VGS = 0 and maximum for VGS negative and large | |
| 757. |
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 | |
| 758. |
The range of visible light is |
| A. | 300 to 2000 √Ö |
| B. | 200 - 4000 √Ö |
| C. | 4000 to 7700 √Ö |
| D. | more than 10000 √Ö |
| Answer» D. more than 10000 √Ö | |
| 759. |
When a large number of atoms are brought together to form a crystal |
| A. | the energy levels of inner shell electrons are affected appreciably by the presence of other neighbouring atoms. |
| B. | The energy levels of outer shell electrons are affected appreciably by the presence of other neighbouring atoms. |
| C. | the energy levels of both inner and outer shell electrons are affected appreciably by the presence of other neighbouring atoms. |
| D. | none of the above. |
| Answer» C. the energy levels of both inner and outer shell electrons are affected appreciably by the presence of other neighbouring atoms. | |
| 760. |
The capacitor filter provides poor voltage regulation because |
| A. | the increase in ripple with load current causes a decrease in average voltage |
| B. | the increase in ripple with load current causes a increase in average voltage |
| C. | filter promotes ripple at peak voltage |
| D. | none of the above |
| Answer» B. the increase in ripple with load current causes a increase in average voltage | |
| 761. |
The behaviour of a JFET is similar to that of |
| A. | NPN transistor |
| B. | PNP transistor |
| C. | SCR |
| D. | Vacuum triode |
| Answer» E. | |
| 762. |
In a forward biased p-n junction current enters p material as hole current and leaves n material as electron current of the same magnitude. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 763. |
The voltage at which Avalanche occurs is known as |
| A. | cut in voltage |
| B. | barrier voltage |
| C. | breakdown voltage |
| D. | depletion voltage |
| Answer» D. depletion voltage | |
| 764. |
A FET is to be operated as voltage variable resistor. For this drain to source voltage VDS should be, |
| A. | 74 |
| B. | #NAME? |
| C. | < VP |
| D. | > VP |
| Answer» D. > VP | |
| 765. |
Thermosetting polymers are |
| A. | injection moulded |
| B. | extruded |
| C. | cast moulded |
| D. | none of the above |
| Answer» D. none of the above | |
| 766. |
Which of the following is known as insulated gate FET? |
| A. | JFET |
| B. | MOSFET |
| C. | Both JFET and MOSFET |
| D. | None of the above |
| Answer» C. Both JFET and MOSFET | |
| 767. |
As compared to bipolar junction transistor, a FET |
| A. | is less noisy |
| B. | has better thermal stability |
| C. | has higher input resistance |
| D. | all of the above |
| Answer» E. | |
| 768. |
Assertion (A): The conductivity of p type semiconductor is higher than that of intrinsic semiconductor. Reason (R): The addition of donor impurity creates additional energy levels below conduction band. |
| 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 | |
| 769. |
Holes and electrons move in opposite directions. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 770. |
A long specimen of P type semiconductor material |
| A. | is + vely charged |
| B. | is electrically neutral |
| C. | has an electric field directed along its length |
| D. | acts as a dipole |
| Answer» C. has an electric field directed along its length | |
| 771. |
Consider the following statements about conditions that make a metal semiconductor contact rectifying N type semiconductor with work function φs more than work function φM of metalN type semiconductor with work function φs less than work function φM of metalP type semiconductor with work function φs more than work function φM of metalP type semiconductor with work function φs less than work function φM of metal. Of these statements |
| A. | 1 and 3 are correct |
| B. | 2 and 3 are correct |
| C. | 1 and 4 are correct |
| D. | 2 and 4 are correct |
| Answer» B. 2 and 3 are correct | |
| 772. |
An electrically neutral semiconductor has |
| A. | no free charges |
| B. | no majority carriers |
| C. | no minority carriers |
| D. | equal number of positive and negative charges |
| Answer» E. | |
| 773. |
The static characteristic of an adequately forward biased P-n junction is a straight line, if the plot is of __________ Vs ‚Üí versus |
| A. | log I Vs log V |
| B. | log I Vs V |
| C. | I Vs log V |
| D. | I Vs V |
| Answer» C. I Vs log V | |
| 774. |
An n type semiconductor is illuminated by a steady flux of photons with energy greater than the band gap energy. The change in conductivity Δσ obeys which relation? [ Here, e is the electron charge, μn electron mobility, μp hole mobility, Δn (Δp) is the excess electron (hole) density ]. |
| A. | Δσ = 0 |
| B. | Δσ = e(σn + σp) Δn |
| C. | Δσ = e(μnΔn - μpΔp) |
| D. | Δσ = e μnΔn |
| Answer» C. ŒîœÉ = e(ŒºnŒîn - ŒºpŒîp) | |
| 775. |
The scaling factor of an MOS device using constant voltage scaling model, the gate area of the device will be scaled as |
| A. | 1/a |
| B. | 1/a2 |
| C. | 1/a3 |
| D. | 1/a4 |
| Answer» E. | |
| 776. |
Which of the following is not a semiconductor? |
| A. | Silicon |
| B. | Calcium arsenide |
| C. | Germanium |
| D. | Zinc sulphide |
| Answer» C. Germanium | |
| 777. |
High purity copper is obtained by |
| A. | rolling casting |
| B. | casting |
| C. | electrolytic refining |
| D. | induction heating |
| Answer» D. induction heating | |
| 778. |
For a junction FET in the pinch off region as the drain voltage is increased, the drain current |
| A. | becomes zero |
| B. | abruptly decreases |
| C. | abruptly increases |
| D. | remains constant |
| Answer» E. | |
| 779. |
When p-n junction is reverse biased the holes in p material move towards the junction and electrons in n material move away from the junction. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 780. |
Consider the following statements: The function of oxide layer in an IC device is to mask against diffusion or non implantinsulate the surface electricallyincrease the melting point of siliconproduce a chemically stable protective layer Of these statements: |
| A. | 1, 2, 3 are correct |
| B. | 1, 3, 4 are correct |
| C. | 2, 3, 4 are correct |
| D. | 1, 2, 4 are correct |
| Answer» E. | |
| 781. |
Which of the following is used for generating time varying wave forms? |
| A. | MOSFET |
| B. | PIN diode |
| C. | Tunnel diode |
| D. | UJT |
| Answer» E. | |
| 782. |
Which of the following could be the maximum current rating of junction diode by 126? |
| A. | 0.041666666666667 |
| B. | 0.41666666666667 |
| C. | 20 A |
| D. | 100 A |
| Answer» B. 0.41666666666667 | |
| 783. |
In an n channel MOSFET, the substrate is connected |
| A. | to negative terminal of battery |
| B. | to positive terminal of battery |
| C. | to either positive or negative terminal of battery |
| D. | none of the above |
| Answer» B. to positive terminal of battery | |
| 784. |
In the BJT amplifier shown in the figure is the transistor is biased in the forward active region. Putting a capacitor across RE will |
| A. | decrease the voltage gain and decrease the I/P impedance |
| B. | increase the voltage gain and decrease the I/P Impedance |
| C. | decrease the voltage gain and Increase the I/P impedance |
| D. | none of the above |
| Answer» C. decrease the voltage gain and Increase the I/P impedance | |
| 785. |
When a diode is not conducting, its bias is |
| A. | forward |
| B. | zero |
| C. | reverse |
| D. | zero or reverse |
| Answer» E. | |
| 786. |
In a vacuum triode μ = rpgm. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 787. |
The power dissipation in a transistor is the product of |
| A. | emitter current and emitter to base voltage |
| B. | emitter current and collector to emitter voltage |
| C. | collector current and collector to emitter voltage |
| D. | none of the above |
| Answer» D. none of the above | |
| 788. |
In a p type material the Fermi level is 0.3 eV above valence band. The concentration of acceptor atoms is increased. The new position of Fermi level is likely to be |
| A. | 0.5 eV above valence band |
| B. | 0.28 eV above valence band |
| C. | 0.1 eV above valence band |
| D. | below the valence band |
| Answer» C. 0.1 eV above valence band | |
| 789. |
Work function of oxide coated cathode is much lower than that of tungsten cathode. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 790. |
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. Œº ohm-cm/¬∞C | |
| 791. |
The forbidden energy gap in semiconductors |
| A. | is always zero |
| B. | lies just below the valence band |
| C. | lies between the valence band and the conduction band |
| D. | lies just above the conduction band |
| Answer» D. lies just above the conduction band | |
| 792. |
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 | |
| 793. |
Varactor diode is forward biased when it is used. |
| A. | 1 |
| B. | |
| C. | gold as an impurity below the contact |
| D. | high concentration of donors below the contact |
| Answer» C. gold as an impurity below the contact | |
| 794. |
What is the effect of cut in voltage on the wave form of output as compared to input in a semiconductor diode? |
| A. | The duration of output waveform is less than 180° |
| B. | Output voltage is less than input voltage |
| C. | Output voltage is more than input voltage |
| D. | Both (a) and (b) |
| Answer» E. | |
| 795. |
Power diodes are generally |
| A. | silicon diodes |
| B. | germanium diodes |
| C. | either of the above |
| D. | none of the above |
| Answer» B. germanium diodes | |
| 796. |
In the circuit of figure the function of resistor R and diode D are |
| A. | to limit the current and to protect LED against over voltage |
| B. | to limit the voltage and to protect LED against over current |
| C. | to limit the current and protect LED against reverse breakdown voltage. |
| D. | none of the above. |
| Answer» D. none of the above. | |
| 797. |
In a bipolar transistor |
| A. | recombination in base regions of both n-p-n and p-n-p transistor is low |
| B. | recombination in base regions of both n-p-n and p-n-p transistors is high |
| C. | recombination in base region of n-p-n transistor is low but that in p-n-p transistor is high |
| D. | recombination in base region of p-n-p transistor is low but that in n-p-n transistor is high |
| Answer» B. recombination in base regions of both n-p-n and p-n-p transistors is high | |
| 798. |
Greatest mobility can be expected in case of |
| A. | holes |
| B. | protons |
| C. | electrons |
| D. | negative ions |
| Answer» D. negative ions | |
| 799. |
The primary reason for the widespread use of Si in semiconductor device technology is |
| A. | abundance of Si on the surface of earth |
| B. | larger band gap of Si in comparison to Ge |
| C. | favourable properties of Silicon-dioxide (SiO2) |
| D. | lower melting point |
| Answer» D. lower melting point | |
| 800. |
Wiedemann-Franz law correlates |
| A. | electrical and thermal conductivities |
| B. | electron arrangement in shells |
| C. | temperature and photo electric emission |
| D. | all of the above |
| Answer» B. electron arrangement in shells | |