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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.
| 651. |
The drain characteristics of JFET are drawn between |
| A. | VGS and VDS for different values of drain current |
| B. | drain current and VGS for different values of VDS |
| C. | drain current and VDS for different values of VGS |
| D. | drain current and VGS for one value of VDS |
| Answer» D. drain current and VGS for one value of VDS | |
| 652. |
Each cell of a static Random Access memory contains |
| A. | 6 MOS transistor |
| B. | 4 MOS transistor, 2 capacitor |
| C. | 2 MOS transistor, 4 capacitor |
| D. | 1 MOS transistor and 1 capacitor |
| Answer» B. 4 MOS transistor, 2 capacitor | |
| 653. |
When an electron breaks a covalent bond and moves away, |
| A. | a hole is created |
| B. | a proton is also lost |
| C. | atom becomes an ion |
| D. | rest of the electron move at a faster rate |
| Answer» B. a proton is also lost | |
| 654. |
Mobility is directly proportional to Hall coefficient. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 655. |
The Ebers-moll equation for IE in CB configuration is given by |
| A. | IE = anICIEC0 |
| B. | IE = aIIC + IC0 |
| C. | IE = anIC + IC0(eqVEB/KT-1) |
| D. | IE = aIIC + IE0(eqVEB/KT - 1) |
| Answer» E. | |
| 656. |
In which of the following device electrons will be the majority carriers? |
| A. | P-type semiconductor |
| B. | N-type semiconductor |
| C. | N-P-N transistor |
| D. | P-N-P transistor |
| Answer» E. | |
| 657. |
For most metals, Fermi level EF is less than |
| A. | 0.1 eV |
| B. | 2 eV |
| C. | 5 eV |
| D. | 10 eV |
| Answer» E. | |
| 658. |
In n type MOSFET, the substrate |
| A. | is p type |
| B. | is n type |
| C. | is metallic |
| D. | may be p or n type |
| Answer» B. is n type | |
| 659. |
The atomic weight of an atom is determined by |
| A. | the number of protons |
| B. | the number of neutrons |
| C. | the number of protons and neutrons |
| D. | the number of electrons and protons |
| Answer» D. the number of electrons and protons | |
| 660. |
At room temperature kT = 0.03 eV. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 661. |
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 | |
| 662. |
The emitter follower is widely used in electronic instrument because |
| A. | its voltage gain is less than unity |
| B. | its voltage gain is very high |
| C. | its O/P Impedance is low and input impedance is high |
| D. | its O/P Impedance is high and I/P impedance is low |
| Answer» D. its O/P Impedance is high and I/P impedance is low | |
| 663. |
Assertion (A): In reverse biased p-n junction, the reverse saturation current is nearly constant if the reverse voltage is less than critical value. Reason (R): The total reverse current is sum of reverse saturation current and surface leakage current. |
| 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 | |
| 664. |
The relation between thermionic emission current and temperature is known as |
| A. | Richardson Dushman equation |
| B. | Langmuir child law |
| C. | Ohm's law |
| D. | Boltzmann's law |
| Answer» B. Langmuir child law | |
| 665. |
Given a power supply filter circuit, what measurements must be made of determine percentage regulation |
| A. | current through and voltage across the capacitor |
| B. | d.c. load voltage and r.m.s. load voltage |
| C. | current through load and voltage across load resistance |
| D. | number of turns and gauge of secondary winding of transformer |
| Answer» C. current through load and voltage across load resistance | |
| 666. |
Fill in the suitable word in the blanks is the following questions. The electron in the outermost orbit is called __________ electron. |
| A. | valence |
| B. | covalent |
| C. | acceptor |
| D. | donor |
| Answer» B. covalent | |
| 667. |
Photo electric emission can occur only if the frequency of light is more than threshold frequency. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 668. |
Intrinsic concentration of charge carriers in a semiconductor varies as |
| A. | T |
| B. | T2 |
| C. | T3 |
| D. | T-2 |
| Answer» D. T-2 | |
| 669. |
The main reason why Ni-Zn ferrites are used for audio and T.V. transformers is that |
| A. | they have large saturation magnetization |
| B. | they are easy to fabricate by rolling |
| C. | they are totally free from pores and voids |
| D. | they have a high electrical resistivity |
| Answer» B. they are easy to fabricate by rolling | |
| 670. |
In a bipolar junction transistor adc = 0.98, ICO= 2 μA and 1B = 15 μA. The collector current IC is |
| A. | 635 mA |
| B. | 735 mA |
| C. | 835 mA |
| D. | 935 mA |
| Answer» C. 835 mA | |
| 671. |
The magnetization 'm' of a superconductor in a field of H is |
| A. | extremely small |
| B. | #NAME? |
| C. | -1 |
| D. | Zero |
| Answer» C. -1 | |
| 672. |
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 | |
| 673. |
The value of a in a transistor |
| A. | is always equal to 1 |
| B. | is less than 1 but more than 0.9 |
| C. | is about 0.4 |
| D. | is about 0.1 |
| Answer» C. is about 0.4 | |
| 674. |
If a sample of germanium and a sample of Si have the impurity density and are kept at room temperature then |
| A. | both will have equal value of resistivity |
| B. | both will have equal -ve resistivity |
| C. | resistivity of germanium will be higher than that of silicon |
| D. | resistivity of Si will be higher than of germanium |
| Answer» E. | |
| 675. |
A CMOS amplifier when compared to an N-channel. MOSFET, has the advantage of |
| A. | higher cut off frequency |
| B. | higher voltage gain |
| C. | higher current gain |
| D. | lower current drain from the power supply, there by less dissipation |
| Answer» B. higher voltage gain | |
| 676. |
Dynamic resistance of diode is |
| A. | 1 |
| B. | |
| Answer» B. | |
| 677. |
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 | |
| 678. |
Reluctivity is analogous to |
| A. | permeability |
| B. | conductivity |
| C. | resistivity |
| D. | retentivity |
| Answer» D. retentivity | |
| 679. |
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 | |
| 680. |
The network shown in the figure represents a |
| A. | band pass filter |
| B. | low pass filter |
| C. | high pass filter |
| D. | band stop filter |
| Answer» B. low pass filter | |
| 681. |
Spot the odd one out |
| A. | aluminium |
| B. | silver |
| C. | porcelain |
| D. | copper |
| Answer» D. copper | |
| 682. |
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 | |
| 683. |
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 | |
| 684. |
The 6 V zener diode shown in figure has zero zener resistance and a knee current of 5 mA. The minimum value of R, so that the voltage across it does not fall below 6 V is |
| A. | 1.2 kΩ |
| B. | 80 Ω |
| C. | 50 W |
| D. | 0 |
| Answer» C. 50 W | |
| 685. |
An intrinsic silicon sample has 1 million free electrons at room temperature. As the temperature is increased |
| A. | the number of free electrons increases |
| B. | the number of free electrons increases but the number of holes decreases |
| C. | the number of free electrons and holes increase by the same amount |
| D. | the number of free electrons and holes increase but not by the same amount |
| Answer» D. the number of free electrons and holes increase but not by the same amount | |
| 686. |
Piezoelectric quartz crystal resonators find application where |
| A. | signal amplification is required |
| B. | rectification of the signal is required |
| C. | signal frequency control is required |
| D. | modulation of signal is required |
| Answer» C. signal frequency control is required | |
| 687. |
The forbidden energy gap between the valence band and conduction band will be least in case of |
| A. | metals |
| B. | semiconductors |
| C. | insulators |
| D. | all of the above |
| Answer» B. semiconductors | |
| 688. |
The addition of impurity in extrinsic semiconductor is about 1 part in 108 parts. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 689. |
Barkhausen criterion of oscillation is |
| A. | Aβ > 1 |
| B. | Aβ = 1 |
| C. | Aβ = < 1 |
| D. | Aβ ≤ 1 |
| Answer» C. AŒ≤ = < 1 | |
| 690. |
Which quantity controls the effectiveness of LED in emitting light? |
| A. | Applied voltage |
| B. | Current |
| C. | Extent of doping |
| D. | Temperature |
| Answer» E. | |
| 691. |
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 | |
| 692. |
The potential of suppressor grid (with respect to cathode) is usually |
| A. | zero |
| B. | negative |
| C. | positive |
| D. | zero or positive |
| Answer» B. negative | |
| 693. |
The depletion layer across a P+ n junction lies |
| A. | mostly in the P+ region |
| B. | mostly in n region |
| C. | equally in both the P+ and n-region |
| D. | entirely in the P+ region |
| Answer» B. mostly in n region | |
| 694. |
The V-I characteristic of a semi-conductor diode is shown in figure. From this figure it can be concluded that |
| A. | The diode is a silicon diode |
| B. | The diode is a germanium diode |
| C. | Break down voltage of the diode is 0.7 V |
| D. | At 1 V rated current will pass through the diode |
| Answer» B. The diode is a germanium diode | |
| 695. |
The conductivity of germanium increases by about 6 percent per degree increase in temperature. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 696. |
Zener breakdown occurs |
| A. | due to rapture of covalent band |
| B. | mostly in germanium junctions |
| C. | in lightly doped junctions |
| D. | due to thermally generated minority carriers |
| Answer» B. mostly in germanium junctions | |
| 697. |
Assertion (A): Field emission is substantially independent of temperature. Reason (R): When a high electric field is created at metal surface field emission may occur. |
| 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 | |
| 698. |
In a varactor diode the increase in width of depletion layer results in |
| A. | decrease in capacitance |
| B. | increase in capacitance |
| C. | no change in capacitance |
| D. | either (a) or (b) |
| Answer» B. increase in capacitance | |
| 699. |
A P-N junction diode dynamic conductance is directly proportional to |
| A. | the applied voltage |
| B. | the temperature |
| C. | its current |
| D. | thermal voltage |
| Answer» D. thermal voltage | |
| 700. |
The process of deliberately adding impurity to a semi-conductor material is called |
| A. | impurification |
| B. | pollution |
| C. | deionisation |
| D. | doping |
| Answer» E. | |