MCQOPTIONS
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MCQOPTIONS
This section includes 9294 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 2701. |
X-rays cannot penetrate through a thick sheet of |
| A. | wood |
| B. | paper |
| C. | lead |
| D. | aluminium |
| Answer» D. aluminium | |
| 2702. |
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 | |
| 2703. |
Gold is often diffused into silicon P-N junction devices to |
| A. | increase recombination rate |
| B. | reduce recombination rate |
| C. | make silicon a direct gap semiconductor |
| D. | make silicon semimetal |
| Answer» C. make silicon a direct gap semiconductor | |
| 2704. |
In a solar cell, the photovoltaic voltages is the voltage at which the resultant current is |
| A. | positive |
| B. | zero |
| C. | negative |
| D. | rated current |
| Answer» C. negative | |
| 2705. |
The forbidden energy gap between the valence band and conduction band will be wide in case of |
| A. | semiconductors |
| B. | all metals |
| C. | good conductors of electricity |
| D. | insulators |
| Answer» E. | |
| 2706. |
At 0 K the forbidden energy gap in intrinsic semi conductor is about |
| A. | 10 eV |
| B. | 6 eV |
| C. | 1 eV |
| D. | 0.2 eV |
| Answer» D. 0.2 eV | |
| 2707. |
The on voltage and forward breakover voltage of an SCR depend on |
| A. | gate current alone |
| B. | band gap of semiconductor alone |
| C. | gate current and semiconductor band gap respectively |
| D. | semiconductor band gap and gate current respectively |
| Answer» E. | |
| 2708. |
EG for silicon is 1.12 eV and that for germanium is 0.72 eV. Therefore, it can be concluded that |
| A. | the conductivity of silicon will be less than that of germanium at room temperature |
| B. | the conductivity of silicon will be more than that of germanium at room temperature |
| C. | the conductivity of two will be same at 60 C |
| D. | the conductivity of two will be same at 100 C |
| Answer» B. the conductivity of silicon will be more than that of germanium at room temperature | |
| 2709. |
Assertion (A): The resistivity of intrinsic semiconductor decreases with increase in temperature. Reason (R): The forbidden gap decreases with increase in temperature. |
| 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 | |
| 2710. |
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 | |
| 2711. |
If 100 V is the peak voltage across the secondary of the transformer in a half-wave rectifier (without any filter circuit), then the maximum voltage on the reverse-biased diode is |
| A. | 200 V |
| B. | 141.4 V |
| C. | 100 V |
| D. | 86 V |
| Answer» C. 100 V | |
| 2712. |
The O/P Power of a power amplifier is several times its input power. It is possible because |
| A. | power amplifier introduces a -ve resistance |
| B. | there is +ve feed back in the circuit |
| C. | step up transformer is use in the circuit |
| D. | power amplifier converts a part of I/P d.c. power into a.c. power |
| Answer» E. | |
| 2713. |
In p type semiconductor holes are majority carriers. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 2714. |
The band gap of silicon at 300K is |
| A. | 1.36 eV |
| B. | 1.10 eV |
| C. | 0.80 eV |
| D. | 0.67 eV |
| Answer» C. 0.80 eV | |
| 2715. |
An m derived and constant k filter section connected in cascade give |
| A. | proper impedance matching |
| B. | proper phase shift characteristic |
| C. | proper attenuation characteristic |
| D. | all of the above |
| Answer» C. proper attenuation characteristic | |
| 2716. |
A short-circuit is that which is |
| A. | used short pieces of wire |
| B. | goes only a short distance |
| C. | is used for dimming light |
| D. | offer very low resistance path for current to flow |
| Answer» E. | |
| 2717. |
Resistivity of electrical conductors is most affected by |
| A. | Pressure |
| B. | temperature |
| C. | composition |
| D. | ageing |
| Answer» C. composition | |
| 2718. |
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 | |
| 2719. |
In bipolar transistors dc current gain is |
| A. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/43-164-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/43-164-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/43-164-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/43-164-4.png"> |
| Answer» C. <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/43-164-3.png"> | |
| 2720. |
Holes and electrons move in opposite directions. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 2721. |
The depletion layer in a reverse biased p-n junction is due to the presence of |
| A. | electrons |
| B. | holes |
| C. | both electrons and holes |
| D. | immobile ions |
| Answer» E. | |
| 2722. |
Which materials find application in MASER? |
| A. | Diamagnetic |
| B. | Paramagnetic |
| C. | Ferromagnetic |
| D. | Ferrimagnetic |
| Answer» B. Paramagnetic | |
| 2723. |
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. | |
| 2724. |
Magnetic recording tape is most commonly made from |
| A. | small particles of iron |
| B. | silicon iron |
| C. | ferric-oxide |
| D. | silver nitrate |
| Answer» D. silver nitrate | |
| 2725. |
The circuit shown in the figure is best described as a |
| A. | bridge rectifier |
| B. | ring modulator |
| C. | frequency discriminator |
| D. | voltage doubler |
| Answer» E. | |
| 2726. |
At a P-N junction, the potential barrier is due to the charges on either side of the junction, which consists of |
| A. | fixed donor and acceptor ions |
| B. | majority carriers only |
| C. | minority carriers only |
| D. | both majority and minority carriers |
| Answer» B. majority carriers only | |
| 2727. |
In a vacuum triode = rpgm. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 2728. |
Highest resistivity of the following is |
| A. | nichrome |
| B. | constantan |
| C. | metal |
| D. | manganin |
| Answer» B. constantan | |
| 2729. |
The material which has zero temperature coefficient of resistance is |
| A. | manganin |
| B. | porcelain |
| C. | carbon |
| D. | aluminium |
| Answer» B. porcelain | |
| 2730. |
When the light falling on a photodiode increases, the reverse minority current |
| A. | increases |
| B. | increases or decreases |
| C. | decreases |
| D. | remains the same |
| Answer» B. increases or decreases | |
| 2731. |
Consider the following statements about conditions that make a metal semiconductor contact rectifying N type semiconductor with work function s more than work function M of metalN type semiconductor with work function s less than work function M of metalP type semiconductor with work function s more than work function M of metalP type semiconductor with work function s less than work function M 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 | |
| 2732. |
Silicon diodes have __________ reverse resistance than germanium diodes. |
| A. | a much smaller |
| B. | a much larger |
| C. | an infinite |
| D. | a negligible |
| Answer» C. an infinite | |
| 2733. |
Resistivity of carbon is around |
| A. | 10 to 70 m-ohm-cm |
| B. | 80 to 130 m-ohm-cm |
| C. | 800 to 1300 m-ohm-cm |
| D. | 8000 to 13000 m-ohm-cm |
| Answer» D. 8000 to 13000 m-ohm-cm | |
| 2734. |
Which of the following is anti-ferromagnetic material? |
| A. | CrSb |
| B. | NIO |
| C. | MnO |
| D. | All of the above |
| Answer» E. | |
| 2735. |
Assertion (A): The capacitance of a reverse biased pin diode is lower than that of reverse biased p-n diode. Reason (R): A PIN diode has an intrinsic layer between p and n regions. |
| 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 | |
| 2736. |
In the saturation region of CE output characteristics of n-p-n transistor, VCE is about |
| A. | 0.5 V |
| B. | 15 V |
| C. | - 0.5 V |
| D. | - 15 V |
| Answer» B. 15 V | |
| 2737. |
For radiating ultraviolet rays, LEDs use |
| A. | zinc sulphide |
| B. | gallium arsenide |
| C. | gallium phosphide |
| D. | none of the above |
| Answer» B. gallium arsenide | |
| 2738. |
The forbidden band in semiconductors is of the order of |
| A. | 6 eV |
| B. | 1 eV |
| C. | 10 eV |
| D. | 0.01 eV |
| Answer» C. 10 eV | |
| 2739. |
For an P-N-P transistor in normal operation its junction are biased as |
| A. | emitter base : reverse, collector base : forward |
| B. | emitter base : forward, collector base : reverse |
| C. | emitter base : forward, collector base : forward |
| D. | emitter base : reverse, collector base : reverse |
| Answer» C. emitter base : forward, collector base : forward | |
| 2740. |
Assertion (A): FET has characteristics very similar to that of pentode. Reason (R): Both FET and pentode are voltage controlled devices. |
| 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 | |
| 2741. |
The current gain of a bipolar transistor drops at high frequencies because of |
| A. | transistor capacitance |
| B. | high current effects in the base |
| C. | parasitic inductive elements |
| D. | the early effect |
| Answer» B. high current effects in the base | |
| 2742. |
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 | |
| 2743. |
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. | |
| 2744. |
In a zener diode |
| A. | forward voltage rating is high |
| B. | negative resistance characteristics exists |
| C. | sharp breakdown occurs at low reverse voltage |
| D. | none of the above |
| Answer» D. none of the above | |
| 2745. |
Which one of the following bipolar transistors has the highest current gain bandwidth Product (fr) for similar geometry? |
| A. | NPN germanium transistor |
| B. | NPN silicon transistor |
| C. | PNP germanium transistor |
| D. | PNP silicon transistor |
| Answer» C. PNP germanium transistor | |
| 2746. |
An increase of reverse voltage decreases the junction capacitance. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 2747. |
The maximum forward current in case of signal diode is in the range of |
| A. | 1 A to 10 A |
| B. | 0.1 A to 1 A |
| C. | few milli amperes |
| D. | few nano amperes |
| Answer» D. few nano amperes | |
| 2748. |
Higher value of ripple factor indicates |
| A. | poor rectification |
| B. | ideal rectification |
| C. | r.m.s. value to peak value |
| D. | none of the above |
| Answer» B. ideal rectification | |
| 2749. |
When a semi-conductor is doped, its electrical conductivity |
| A. | increases |
| B. | decreases in the direct ratio of the doped material |
| C. | decreases in the inverse ratio of the doped material |
| D. | remains unaltered |
| Answer» B. decreases in the direct ratio of the doped material | |
| 2750. |
The conduction band is |
| A. | same as forbidden energy gap |
| B. | generally located on the top of the crystal |
| C. | generally located on the bottom of the crystal |
| D. | a range of energies corresponding to the energies of the free electrons |
| Answer» E. | |