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.
| 701. |
A varactor diode is used for |
| A. | tuning |
| B. | rectification |
| C. | amplification |
| D. | rectification and amplification |
| Answer» B. rectification | |
| 702. |
The output V-I characteristics of an Enhancement type MOSFET has |
| A. | only an ohmic region |
| B. | only a saturation region |
| C. | an ohmic region at low voltage value followed by a saturation region at higher voltages. |
| D. | an ohmic region at large voltage values. Preceded by a saturation region at lower voltages. |
| Answer» D. an ohmic region at large voltage values. Preceded by a saturation region at lower voltages. | |
| 703. |
The sum of two or more arbitrary sinusoidal is |
| A. | always periodic |
| B. | periodic under certain conditions |
| C. | never periodic |
| D. | periodic only if all the sinusoidals are identical in frequency and phase |
| Answer» E. | |
| 704. |
Assertion (A): A JFET can be used as a current source. Reason (R): In beyond pinch off region the current in JFET is nearly constant. |
| 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 | |
| 705. |
In what condition does BJT act like an open switch |
| A. | cut off |
| B. | saturation |
| C. | active |
| D. | both (b) and (c) |
| Answer» B. saturation | |
| 706. |
GaAs has an energy gap 1.43 eV the optical cut off wavelength of GaAs would lie in the |
| A. | visible region of the spectrum |
| B. | infrared region of the spectrum |
| C. | ultraviolet region of the spectrum |
| D. | for ultraviolet region of the spectrum |
| Answer» C. ultraviolet region of the spectrum | |
| 707. |
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 | |
| 708. |
Assertion (A): When a zener diode breakdown, occurs the voltage across it is constant. Reason (R): The upper limit of zener current is determined by power handling capacity. |
| 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 | |
| 709. |
When a substance is repelled by a magnetic field it is known as |
| A. | ferromagnetic |
| B. | antiferromagnetic |
| C. | diamagnetic |
| D. | paramagnetic |
| Answer» D. paramagnetic | |
| 710. |
Assertion (A): In a BJT, the base region is very thick. Reason (R): In p-n-p transistor most of holes given off by emitter diffuse through the base. |
| 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. | |
| 711. |
A diode is operating in forward region and the forward voltage and current are v = 3 + 0.3 sin ωt (volts) and i = 5 + 0.2 sin ωt (mA). The average power dissipated is |
| A. | 15 mW |
| B. | about 15 mW |
| C. | 1.5 mW |
| D. | about 1.5 mW |
| Answer» C. 1.5 mW | |
| 712. |
If both emitter base and collector base junctions of a BJT are forward biased, the transistor is in |
| A. | active region |
| B. | saturated region |
| C. | cut off region |
| D. | inverse mode |
| Answer» C. cut off region | |
| 713. |
Atomic number of germanium is |
| A. | 24 |
| B. | 28 |
| C. | 32 |
| D. | 36 |
| Answer» D. 36 | |
| 714. |
The mean life time of carrier may range from 10-9 seconds to hundreds of μ-seconds. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 715. |
Assertion (A): In p type semiconductor conduction is mainly due to holes. Reason (R): In p type material the holes are majority carriers. |
| 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 | |
| 716. |
When the i-v curve of a photodiode passes through origin the illumination is |
| A. | maximum |
| B. | minimum |
| C. | zero |
| D. | equal to rated value |
| Answer» D. equal to rated value | |
| 717. |
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 | |
| 718. |
Addition of 0.3 to 3.5% silicon to iron |
| A. | increases the electrical resistivity of iron |
| B. | decreases the electrical resistivity of iron |
| C. | does not change electrical resistivity of iron |
| D. | silicon can't be added with iron |
| Answer» B. decreases the electrical resistivity of iron | |
| 719. |
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. | |
| 720. |
For BJT, under saturation condition |
| A. | IC = βIB |
| B. | IC > bIB |
| C. | IC is independent of all other parameters |
| D. | IC < βIB |
| Answer» C. IC is independent of all other parameters | |
| 721. |
Resistivity of copper is nearly |
| A. | 1.56 μ ohm-cm |
| B. | 3.95 μ ohm-cm |
| C. | 14.55 μ ohm-cm |
| D. | 22.05 μ ohm-cm |
| Answer» B. 3.95 Œº ohm-cm | |
| 722. |
In an ideal diode there is no breakdown, no __________ current, and no forward __________ drop. |
| A. | reverse, voltage |
| B. | forward, current |
| C. | forward, voltage |
| D. | reverse, current |
| Answer» B. forward, current | |
| 723. |
An enhancement mode MOSFET is off when the gate voltage is |
| A. | zero |
| B. | negative |
| C. | less than threshold value |
| D. | none of the above |
| Answer» D. none of the above | |
| 724. |
Ohmic range of metal film resistors is |
| A. | 1 to 100 ohms |
| B. | 10 to 1 K ohms |
| C. | 100 to 1 M ohms |
| D. | 100 to 100 M ohms |
| Answer» D. 100 to 100 M ohms | |
| 725. |
The collector to emitter cutoff current (ICE0) of a transmitter is related to collector to base cut off current (ICB0) as |
| A. | ICE0 = ICB0 |
| B. | ICE0 = a ICB0 |
| C. | ICE0 = |
| D. | ICE0 = |
| Answer» D. ICE0 = | |
| 726. |
When a normal atom loses an electron |
| A. | the atom loses one-proton simultaneously |
| B. | rest of the electrons move faster |
| C. | the atom becomes a positive ion |
| D. | the atom becomes a negative ion |
| Answer» D. the atom becomes a negative ion | |
| 727. |
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) | |
| 728. |
In an n channel JFET |
| A. | ID, IS and IG are considered positive when flowing into the transistor |
| B. | ID and IS are considered positive when flowing into transistor and IG is considered positive when flowing out of it |
| C. | ID, IS, IG are considered positive when flowing out of transistor |
| D. | IS and IG are considered positive when flowing into transistor and ID is considered positive when flowing out of it |
| Answer» B. ID and IS are considered positive when flowing into transistor and IG is considered positive when flowing out of it | |
| 729. |
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 | |
| 730. |
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 | |
| 731. |
In a semiconductor avalanche breakdown occurs when |
| A. | reverse bias exceeds the limiting value |
| B. | forward bias exceeds the limiting value |
| C. | forward current exceeds the limiting value |
| D. | potential barrier is reduced to zero |
| Answer» B. forward bias exceeds the limiting value | |
| 732. |
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. | |
| 733. |
An LED is |
| A. | an ohmic device |
| B. | a display device |
| C. | a voltage regulated device |
| D. | all of the above |
| Answer» C. a voltage regulated device | |
| 734. |
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 | |
| 735. |
In a conductor the conduction and valence bands overlap |
| A. | 1 |
| B. | |
| Answer» B. | |
| 736. |
Human body cannot sustain electric current beyond |
| A. | 1 μA |
| B. | 10 μA |
| C. | 5 μA |
| D. | 35 μA |
| Answer» E. | |
| 737. |
Conductivity σ, mobility μ and Hall coefficient KH are related as |
| A. | μ = σKH |
| B. | σ = μKH |
| C. | KH = μσ |
| D. | KH =(μσ)1.1 |
| Answer» B. œÉ = ŒºKH | |
| 738. |
Transconductance indicates the |
| A. | control of output voltage by input voltage |
| B. | control of output current by input voltage |
| C. | control of input voltage by output current |
| D. | control of input current by input voltage |
| Answer» C. control of input voltage by output current | |
| 739. |
Lowest noise can be expected in case of |
| A. | carbon composition resistors |
| B. | carbon film resistors |
| C. | tin oxide resistors |
| D. | metal film resistors |
| Answer» E. | |
| 740. |
The resistance of a metallic wire would |
| A. | increase as the operating frequency increase |
| B. | decrease as the operating frequency increase |
| C. | remain unaffected on increasing the operating frequency |
| D. | first increase then decrease |
| Answer» C. remain unaffected on increasing the operating frequency | |
| 741. |
Which of the following constitutes an active component? |
| A. | Semiconductor device |
| B. | Resistors |
| C. | Capacitors |
| D. | Inductors |
| Answer» B. Resistors | |
| 742. |
Electrical contact materials used in switches, brushes and relays must possess |
| A. | high thermal conductivity and high melting point |
| B. | low thermal conductivity and low melting point |
| C. | high thermal conductivity and low melting point |
| D. | low thermal conductivity and high melting point |
| Answer» B. low thermal conductivity and low melting point | |
| 743. |
At absolute temperature |
| A. | the forbidden energy gap in germanium is higher than that in silicon |
| B. | the forbidden energy gap in germanium and silicon are equal |
| C. | the forbidden energy gap in silicon is higher than that in germanium |
| D. | none of the above |
| Answer» D. none of the above | |
| 744. |
The phenomenon known as "Early effect" in a BJT refers to a reduction of the effective base width caused by |
| A. | electron-hole recombination at the base |
| B. | reverse biasing of the base collector junction |
| C. | forward biasing of emitter base junction |
| D. | the early removal of stored base charge during saturation to cut off switching |
| Answer» C. forward biasing of emitter base junction | |
| 745. |
Dielectric loss due to polarisation occurs in |
| A. | bipolar dielectrics |
| B. | non-metallic dielectrics |
| C. | liquid dielectrics |
| D. | all of the above |
| Answer» B. non-metallic dielectrics | |
| 746. |
Figure shows small signal common base transistor circuit.The current source I and resistor R on the output side are |
| A. | ie and re |
| B. | ie and (1 - a)re |
| C. | (1 - a)ie and (1 - a)re |
| D. | a ie and re |
| Answer» E. | |
| 747. |
To produce p type semiconductor we add |
| A. | acceptor atoms |
| B. | donor atoms |
| C. | pentavalent impurity |
| D. | trivalent impurity |
| Answer» E. | |
| 748. |
In a triode |
| A. | grid is nearer to cathode than anode |
| B. | grid is nearer to anode than cathode |
| C. | grid is equidistant from anode and cathode |
| D. | any of the above |
| Answer» B. grid is nearer to anode than cathode | |
| 749. |
A power supply has full-load voltage of 20 V. What will be its no load voltage when its voltage regulation is 100% |
| A. | 0 V |
| B. | 10 V |
| C. | 20 V |
| D. | 40 V |
| Answer» E. | |
| 750. |
Almost all resistors are made in a monolithic integrated circuit |
| A. | during the entire diffusion |
| B. | while growing the epitaxial layer |
| C. | during the base diffusion |
| D. | during the collector diffusion |
| Answer» B. while growing the epitaxial layer | |