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.
| 2651. |
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 | |
| 2652. |
The conductivity of a semiconductor crystal due to any current carrier is not proportional to |
| A. | mobility of the carrier |
| B. | effective density of states in the conduction band |
| C. | electronic charge |
| D. | surface states in the semiconductor |
| Answer» B. effective density of states in the conduction band | |
| 2653. |
In n channel JFET, the gate voltage is made more negative |
| A. | the channel width will increase |
| B. | the channel width will decrease |
| C. | the channel width and drain current will decrease |
| D. | the channel width will decrease and drain current will increase |
| Answer» D. the channel width will decrease and drain current will increase | |
| 2654. |
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 | |
| 2655. |
At absolute zero temperature a semiconductor behaves like |
| A. | an insulator |
| B. | a super conductor |
| C. | a good conductor |
| D. | a variable resistor |
| Answer» B. a super conductor | |
| 2656. |
In a 741 OP-amp, there is 20 dB/decade fall-off starting at a relatively low frequency. This is due to |
| A. | applied load |
| B. | internal compensation |
| C. | impedance of the source |
| D. | power dissipation in the chip |
| Answer» E. | |
| 2657. |
Typical value of reverse current in a semiconductor diode is |
| A. | 1 A |
| B. | 0.1 A |
| C. | 1 A |
| D. | 0.1 A |
| Answer» E. | |
| 2658. |
Which of the following element has four valence electrons? |
| A. | Silicon |
| B. | Germanium |
| C. | Both (a) and (b) above |
| D. | None of the above |
| Answer» D. None of the above | |
| 2659. |
In a transistor operating in forward active mode |
| A. | depletion layer between emitter and base is thin and that between base and collector is also thin |
| B. | both depletion regions are thick |
| C. | depletion layer between emitter and base is thin and that between base and collector is thick |
| D. | depletion layer between emitter and base is thick and that between base and collector is thin |
| Answer» D. depletion layer between emitter and base is thick and that between base and collector is thin | |
| 2660. |
In standard TTL, the 'totem pole' stage refers to |
| A. | the multi-emitter I/P stage |
| B. | phase splitter |
| C. | the O/P buffer |
| D. | open collector O/P stage |
| Answer» D. open collector O/P stage | |
| 2661. |
In p type semiconductor, the hole concentration |
| A. | is nearly equal to density of acceptor atoms |
| B. | is much greater than density of acceptor atoms |
| C. | is much less than density of acceptor atoms |
| D. | may be equal to or more or less than density of acceptor atoms |
| Answer» B. is much greater than density of acceptor atoms | |
| 2662. |
Which of the following material can be used in cable shields? |
| A. | Copper |
| B. | Aluminium |
| C. | Cast iron |
| D. | Lead |
| Answer» E. | |
| 2663. |
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 | |
| 2664. |
A bistable multivibrator |
| A. | has no stable state |
| B. | has one stable state |
| C. | has two stable state |
| D. | none of the above |
| Answer» D. none of the above | |
| 2665. |
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 | |
| 2666. |
The atomic number of silicon is 14. It can be therefore concluded that |
| A. | a silicon atom contains 14 protons |
| B. | a silicon atom contains 14 neutrons |
| C. | a silicon atom contains 14 electrons |
| D. | all of the above |
| Answer» E. | |
| 2667. |
The main purpose of using transformer coupling in a class A amplifier is to make it more |
| A. | efficient |
| B. | less costly |
| C. | less bulky |
| D. | distortion free |
| Answer» E. | |
| 2668. |
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 | |
| 2669. |
Which of the following element does not have three valence electrons? |
| A. | Boron |
| B. | Aluminium |
| C. | Gallium |
| D. | Phosphorus |
| Answer» E. | |
| 2670. |
Which of the following is used in the sterilization of water? |
| A. | Hydrogen bromide |
| B. | Oxygen |
| C. | Ozone |
| D. | Caustic potash |
| Answer» D. Caustic potash | |
| 2671. |
Electrons within a metal have energy levels from zero to Fermi level EF. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 2672. |
The function off an oxide layer in an IC device is to mask against diffusion or ion implantationinsulate the surface electricallyincrease the melting point of Siproduce a chemically stable protective layer |
| A. | 1, 2, 3 |
| B. | 1, 3, 4 |
| C. | 2, 3, 4 |
| D. | 4, 1, 2 |
| Answer» E. | |
| 2673. |
The passage of current in an electrolyte is due to the movement of |
| A. | electrons |
| B. | molecules |
| C. | atoms |
| D. | ions |
| Answer» E. | |
| 2674. |
AE 139 is a |
| A. | tunnel diode |
| B. | germanium power transistor |
| C. | photoconductive cell |
| D. | silicon diode |
| Answer» C. photoconductive cell | |
| 2675. |
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 | |
| 2676. |
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. | |
| 2677. |
Assertion (A): In n-p-n transistor conduction is mainly due to electrons. Reason (R): In n type materials electrons 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 | |
| 2678. |
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 | |
| 2679. |
Breakdown in dielectric may be |
| A. | electrical breakdown |
| B. | thermal breakdown |
| C. | electrochemical breakdown |
| D. | any of the above |
| Answer» E. | |
| 2680. |
The factor n in the equation for calculating current for a silicon diode is |
| A. | 1 |
| B. | 2 |
| C. | 2.5 |
| D. | 2 for low levels of current and 1 for high levels of current |
| Answer» E. | |
| 2681. |
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 | |
| 2682. |
An enhancement mode MOSFET is on when the gate voltage is |
| A. | zero |
| B. | positive |
| C. | high |
| D. | more threshold value |
| Answer» E. | |
| 2683. |
For the n-type semiconductor with n = NP and P = , the hole concentration will fall below the intrinsic value because some of the holes |
| A. | drop back to acceptor impurity states. |
| B. | drop to donor impurity states |
| C. | virtually leave the crystal |
| D. | recombine with the electrons. |
| Answer» E. | |
| 2684. |
Secondary emission results |
| A. | when temperature of metals is raised to a level above the crystallization temperature |
| B. | when metals are subjected to strong magnetic fields |
| C. | when light rays fall on the metal surface |
| D. | when a high velocity beam of electrons strikes as metal surface |
| Answer» C. when light rays fall on the metal surface | |
| 2685. |
Ohmic range of carbon composition resistors is |
| A. | 10 to 100 ohms |
| B. | 10 to 10 K ohms |
| C. | 10 to 200 ohms |
| D. | 10 to 25 M ohms |
| Answer» E. | |
| 2686. |
The depletion layer consists of immobile ions. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 2687. |
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. | |
| 2688. |
What is the function of silicon dioxide layer in MOSFETS? |
| A. | To provide high input resistance |
| B. | To increase current carriers |
| C. | To provide high output resistance |
| D. | Both (a) and (c) |
| Answer» B. To increase current carriers | |
| 2689. |
Assertion (A): In intrinsic semiconductors, the charge concentration increases with temperature. Reason (R): At higher temperatures, the forbidden energy gap in semiconductors is lower. |
| 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 | |
| 2690. |
Covalent bond energy in Germanium is approximately |
| A. | 3.8 eV |
| B. | 4.7 eV |
| C. | 7.4 eV |
| D. | 12.5 eV |
| Answer» D. 12.5 eV | |
| 2691. |
Mobility is directly proportional to Hall coefficient. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 2692. |
The energy of one quantum of light equal to hf. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 2693. |
For most metals, Fermi level EF is less than |
| A. | 0.1 eV |
| B. | 2 eV |
| C. | 5 eV |
| D. | 10 eV |
| Answer» E. | |
| 2694. |
The spins in a ferrimagnetic material are |
| A. | all aligned parallel |
| B. | partially aligned antiparallel without exactly cancelling out sublattice magnetisation |
| C. | randomly oriented |
| D. | all aligned antiparallel such that the sublattice cancels out exactly |
| Answer» C. randomly oriented | |
| 2695. |
The permeability of soft iron can be increased by |
| A. | purifying it |
| B. | reducing carbon percentage |
| C. | alloying with cobalt |
| D. | increasing percentage |
| Answer» D. increasing percentage | |
| 2696. |
All of the following elements have three valence electrons EXCEPT |
| A. | boron |
| B. | indium |
| C. | gallium |
| D. | arsenic |
| Answer» E. | |
| 2697. |
n channel FETs are better as compared to p-channel FET because |
| A. | they are more efficient |
| B. | they have high switching time |
| C. | they have higher input impedance |
| D. | mobility of electrons is more than that of holes |
| Answer» E. | |
| 2698. |
A-P type material has an acceptor ion concentration of 1 x 1016 per cm3. Its intrinsic carrier concentration is 1.48 x 1010/ cm. The hole and electron mobilities are 0.05m2/V-sec and 0.13 m2/V-sec respectively calculate the resistivity of the material |
| A. | 12.5 Ω-cm |
| B. | 1.25 Ω-cm |
| C. | 0.125 Ω-cm |
| D. | 125 Ω-cm |
| Answer» C. 0.125 Ω-cm | |
| 2699. |
Resistivity is a property of a semiconductor that depends on |
| A. | the atomic weight of the semiconductor |
| B. | the atomic number of the semiconductor |
| C. | the atomic nature of the semiconductor |
| D. | the shape of the semiconductor |
| Answer» D. the shape of the semiconductor | |
| 2700. |
Figure represents a |
| A. | Tunnel diode |
| B. | Zener diode |
| C. | Photo diode |
| D. | Photo sensitive diode |
| Answer» C. Photo diode | |