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.
| 2951. |
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 | |
| 2952. |
The behaviour of a JFET is similar to that of |
| A. | NPN transistor |
| B. | PNP transistor |
| C. | SCR |
| D. | Vacuum triode |
| Answer» E. | |
| 2953. |
The voltage across the secondary of the transformer in a half wave rectifier with a shunt capacitor filter is 50 volts. The maximum voltage that will occur on the reverse biased diode will be |
| A. | 100 V |
| B. | 88 V |
| C. | 50 V |
| D. | 25 V |
| Answer» B. 88 V | |
| 2954. |
Assertion (A): The forward resistance of a p-n diode is not constant. Reason (R): The v-i characteristics of p-n diode is non-linear. |
| 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 | |
| 2955. |
For a photoengraving the mask used is |
| A. | master mask |
| B. | slave mask |
| C. | working mask |
| D. | photo mask |
| Answer» D. photo mask | |
| 2956. |
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 | |
| 2957. |
In given figure a silicon diode is carrying a constant current of 1 mA. When the temperature of the diode is 20 C, VD is found to be 700 mV. If the temperature rises to 40 C, VD becomes approximately equal to |
| A. | 747 mV |
| B. | 660 mV |
| C. | 680 mV |
| D. | 700 mV |
| Answer» B. 660 mV | |
| 2958. |
The work function of a photo surface whose threshold wave length is 1200 A, will be |
| A. | 0.103 eV |
| B. | 0.673 eV |
| C. | 1.03 eV |
| D. | 1.27 eV |
| Answer» D. 1.27 eV | |
| 2959. |
Assertion (A): Oxide coated cathodes are very commonly used. Reason (R): Work function of oxide coated cathode is 1 eV whereas it is 4.5 eV for pure tungsten. |
| 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 | |
| 2960. |
Photoconductive devices uses |
| A. | metallic conductors |
| B. | good quality insulators |
| C. | semiconductors |
| D. | either (a) or (c) |
| Answer» D. either (a) or (c) | |
| 2961. |
A semiconductor diode is biased in forward direction and carrying current I. The current due to holes in p material is |
| A. | I |
| B. | 0 |
| C. | less than I |
| D. | 0.5 |
| Answer» D. 0.5 | |
| 2962. |
Between which regions does BJT act like switch? |
| A. | Cut off and saturation |
| B. | Cut off and forward active |
| C. | Forward active and cut off |
| D. | Saturation and active |
| Answer» B. Cut off and forward active | |
| 2963. |
Assertion (A): When a photoconductive device is exposed to light, its bulk resistance increases. Reason (R): When exposed to light, electron hole pairs are generated in the photoconductive device. |
| 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. | |
| 2964. |
Which of the following elements act as donor impurities? GoldPhosphorusBoronAntimonyArsenicIndium Select the answer using the following codes : |
| A. | 1, 2 and 3 |
| B. | 1, 2, 4, and 6 |
| C. | 3, 4, 5 and 6 |
| D. | 2, 4 and 5 |
| Answer» E. | |
| 2965. |
Light dependent resistor is |
| A. | photo resistive device |
| B. | photo voltaic device |
| C. | photo emissive device |
| D. | either (a) or (c) |
| Answer» B. photo voltaic device | |
| 2966. |
Assertion (A): A high junction temperature may destroy a diode. Reason (R): As temperature increases the reverse saturation current increases. |
| 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 | |
| 2967. |
The number of p-n junctions in a semiconductor diode are |
| A. | 0 |
| B. | 1 |
| C. | 2 |
| D. | 1 or 2 |
| Answer» C. 2 | |
| 2968. |
A voltage of 9 V is applied in forward direction to a semiconductor diode in series with a load resistance of 1000 Ω. The voltage across the load resistance is zero. It indicates that |
| A. | diode is short circuited |
| B. | diode is open circuited |
| C. | resistor is open circuited |
| D. | diode is either o.c or s.c |
| Answer» C. resistor is open circuited | |
| 2969. |
If the drift velocity of holes under a field gradient of 100 V/m in 5 m/s, their mobility (in SI units) is |
| A. | 0.05 |
| B. | 0.5 |
| C. | 50 |
| D. | 500 |
| Answer» B. 0.5 | |
| 2970. |
When a diode is not conducting, its bias is |
| A. | forward |
| B. | zero |
| C. | reverse |
| D. | zero or reverse |
| Answer» E. | |
| 2971. |
The SCR would be turned OFF by voltage reversal of applied anode-cathode ac supply of frequency of |
| A. | 30 kHz |
| B. | 15 kHz |
| C. | 5 kHz |
| D. | 20 kHz |
| Answer» D. 20 kHz | |
| 2972. |
The number of valence electrons in a donor atom is |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 5 |
| Answer» E. | |
| 2973. |
An increase in junction temperature of a semiconductor diode |
| A. | causes a small increase in reverse saturation current |
| B. | causes a large increase in reverse saturation current |
| C. | does not affect reverse saturation current |
| D. | may cause an increase or decrease in reverse saturation current depending on rating of diode |
| Answer» C. does not affect reverse saturation current | |
| 2974. |
An air gap provided in the iron core of an inductor prevents |
| A. | flux leakage |
| B. | hysteresis loss |
| C. | core saturation |
| D. | heat generation |
| Answer» D. heat generation | |
| 2975. |
Generally, the gain of a transistor amplifier falls at high frequency due to the |
| A. | internal capacitance of the device |
| B. | coupling capacitor at the I/P |
| C. | skin effect |
| D. | coupling capacitor at the O/P |
| Answer» B. coupling capacitor at the I/P | |
| 2976. |
Which of these has a layer of intrinsic semiconductor? |
| A. | Zener diode |
| B. | PIN diode |
| C. | Photo diode |
| D. | Schottky diode |
| Answer» C. Photo diode | |
| 2977. |
For an P-channel enhancement type MOSFET determine the drain current if K = 0.278 x 10-3A/V2, VGS = -4V, VT = -2V, Voltage equivalent at 27 C = 26 mV. |
| A. | 10 mA |
| B. | 1.11 mA |
| C. | 0.751 mA |
| D. | 46.98 mA |
| Answer» C. 0.751 mA | |
| 2978. |
Which of these has 3 layers? |
| A. | PIN diode |
| B. | Zener diode |
| C. | Schottky diode |
| D. | Photo diode |
| Answer» B. Zener diode | |
| 2979. |
The skin depth of copper is found to be 66 mm at 1 MHz at a certain temperature. At the same temperature and at 2 MHz, the skin depth would be approximately |
| A. | 47 m |
| B. | 33 m |
| C. | 92 m |
| D. | 1.22 m |
| Answer» B. 33 m | |
| 2980. |
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. | True |
| B. | False |
| Answer» C. | |
| 2981. |
Assertion (A): Power transistors are more commonly of silicon npn type. Reason (R): The fabrication of silicon npn transistors is easy. |
| 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 | |
| 2982. |
In N-type semiconductor |
| A. | electrons are majority carriers while holes are minority carriers |
| B. | electrons are majority carriers while holes are majority carriers |
| C. | both electrons as well as holes are majority carriers |
| D. | both electrons as well as holes are minority carriers |
| Answer» B. electrons are majority carriers while holes are majority carriers | |
| 2983. |
The addition of n type impurity to intrinsic material creates allowable energy levels. |
| A. | slightly below conduction band |
| B. | slightly above conduction band |
| C. | slightly below valence band |
| D. | slightly above valence band |
| Answer» B. slightly above conduction band | |
| 2984. |
Which of the following elements act as donor impurities? GoldPhosphorusBoronAntimonyArsenicIndium Select the correct answer using the codes given below: |
| A. | 1, 2, 3 |
| B. | 1, 2, 4, 6 |
| C. | 3, 4, 5, 6 |
| D. | 2, 4, 5 |
| Answer» E. | |
| 2985. |
The output characteristics of a bipolar transistor has three distinct regions. They are known as |
| A. | saturation region, active region and breakdown region |
| B. | inactive region, active region and breakdown region |
| C. | inactive region, saturation region and active region |
| D. | inactive region, saturation region and breakdown region |
| Answer» B. inactive region, active region and breakdown region | |
| 2986. |
Assertion (A): In a BJT, adc is about 0.98. Reason (R): In a BJT, recombination in base region is high. |
| 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» D. A is false but R is true | |
| 2987. |
Wienbridge oscillator uses |
| A. | -ve feedback |
| B. | +ve feedback |
| C. | both +ve, -ve feedback |
| D. | feedback is not required |
| Answer» D. feedback is not required | |
| 2988. |
Which of the following material is preferred for transformer cores operating in micro wave frequency range? |
| A. | Ferrites |
| B. | Silicon steel |
| C. | Superalloy |
| D. | Copper |
| Answer» B. Silicon steel | |
| 2989. |
The ac resistance of a forward biased p-n junction diode operating at a bias voltage V and carrying current 'I' is |
| A. | 0 |
| B. | constant value independent of V and I |
| C. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/57-453-1.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/57-453-2.png"> |
| Answer» D. <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/57-453-2.png"> | |
| 2990. |
Which of the following diode is designed to operate in the breakdown region? |
| A. | Signal diode |
| B. | Power diode |
| C. | Zener diode |
| D. | None of the above |
| Answer» D. None of the above | |
| 2991. |
A silicon diode is forward biased and total applied voltage is 5 V. The voltage across p-n junction is |
| A. | 5 V |
| B. | Slightly less than 5 V |
| C. | 0.7 V |
| D. | 0 |
| Answer» D. 0 | |
| 2992. |
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 | |
| 2993. |
Assertion (A): In CE connection of n-p-n transistor. VCE is positive. Reason (R): In BJT, the base collector junction is reverse biased. |
| 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 | |
| 2994. |
Assertion (A): Tunnel diode is used in many pulse and digital circuits. Reason (R): The v-i curve of a tunnel diode resembles letter 'N'. |
| 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 | |
| 2995. |
In ferromagnetic materials |
| A. | the atomic magnetic moments are antiparallel and unequal |
| B. | the atomic magnetic moments are parallel |
| C. | the constituent is iron only |
| D. | one of the constituents is iron |
| Answer» C. the constituent is iron only | |
| 2996. |
Which one of the following circuits is most suitable as an oscillator at a frequency of 100Hz? |
| A. | Hartley oscillator |
| B. | Colpitts oscillator |
| C. | Crystal oscillator |
| D. | Twin-T oscillator |
| Answer» B. Colpitts oscillator | |
| 2997. |
Varactor diode is forward biased when it is used. |
| A. | True |
| B. | False |
| Answer» C. | |
| 2998. |
A good ohmic contact on a P-type semiconductor chip is formed by introducing |
| A. | gold as an impurity below the contact |
| B. | high concentration of donors below the contact |
| C. | high concentration of acceptors below the contact |
| D. | thin insulator layer between the metal and semiconductor |
| Answer» C. high concentration of acceptors below the contact | |
| 2999. |
In n type semiconductor, the free electron concentration |
| A. | is nearly equal to density of donor atoms |
| B. | is much greater than density of donor atoms |
| C. | is much less than density of donor atoms |
| D. | may be equal to or more or less than density of donor atoms |
| Answer» B. is much greater than density of donor atoms | |
| 3000. |
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 | |