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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.
| 4101. |
In LED the radiation is in |
| A. | visible region |
| B. | infrared region |
| C. | both (a) and (b) |
| D. | neither (a) nor (b) |
| Answer» E. | |
| 4102. |
When P-N junction is in forward bias, by increasing the battery voltage |
| A. | current through P-N junction reduces |
| B. | current through P-N junction increases |
| C. | circuit resistance increases |
| D. | none of the above |
| Answer» C. circuit resistance increases | |
| 4103. |
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 | |
| 4104. |
A semiconductor in its purest form called |
| A. | intrinsic semiconductor |
| B. | extrinsic semiconductor |
| C. | P-type semiconductor |
| D. | N-type semiconductor |
| Answer» B. extrinsic semiconductor | |
| 4105. |
Which of the following is an active device? |
| A. | Transformer |
| B. | Silicon controlled rectifier |
| C. | Electric bulb |
| D. | Loudspeaker |
| Answer» C. Electric bulb | |
| 4106. |
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 | |
| 4107. |
If E (i.e., available energy state) = EF(i.e., Fermi level), then probability that state E will be occupied is 0.5 for any temperature T. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 4108. |
In a junction transistor biased for operation at emitter current 'IE' and collector current 'IC' the transconductance 'gm' is. |
| A. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/57-443-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/57-443-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/57-443-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/57-443-4.png"> |
| Answer» C. <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/57-443-3.png"> | |
| 4109. |
Ferrities are particularly suited for high frequency applications because of their |
| A. | low distortion |
| B. | low eddy current loss |
| C. | high conductivity |
| D. | high mobility |
| Answer» C. high conductivity | |
| 4110. |
In intrinsic semiconductor, the fermi level |
| A. | lies at the centre of forbidden energy gap |
| B. | is near the conduction band |
| C. | is near the valence band |
| D. | may be anywhere in the forbidden energy gap |
| Answer» B. is near the conduction band | |
| 4111. |
Electromagnetic waves transport |
| A. | energy only |
| B. | momentum only |
| C. | energy as well as momentum |
| D. | neither energy nor momentum |
| Answer» D. neither energy nor momentum | |
| 4112. |
In a forward biased p-n junction current enters p material as hole current and leaves n material as electron current of the same magnitude. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 4113. |
An amplifier with resistive -ve feedback has two left poles in its open loop transfer function. The amplifier |
| A. | will always be unstable at high frequencies |
| B. | will be stable for all frequencies |
| C. | may be unstable, depending on the feedback factor |
| D. | will oscillate at low frequencies |
| Answer» C. may be unstable, depending on the feedback factor | |
| 4114. |
Holes act like |
| A. | positive charges |
| B. | neutral atoms |
| C. | negative charges |
| D. | crystals |
| Answer» B. neutral atoms | |
| 4115. |
Assertion (A): Silicon is less sensitive to changes in temperature than germanium. Reason (R): It is more difficult to produce minority carriers in silicon than in germanium. |
| 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 | |
| 4116. |
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 | |
| 4117. |
A cascade amplifier stage is equivalent to |
| A. | a common emitter stage followed by a common stage |
| B. | a common base stage followed by an emitter follower |
| C. | an emitter follower stage followed by a common base stage |
| D. | a common base stage followed by a common emitter stage |
| Answer» B. a common base stage followed by an emitter follower | |
| 4118. |
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 | |
| 4119. |
Assertion (A): When light falls at junction of p-n photodiode, its p side becomes positive and n side becomes negative. Reason (R): When a photodiode is short circuited, the current in the external circuit flows from p side to n side. |
| 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 | |
| 4120. |
In a JFET |
| A. | gate source cut off voltage is equal to V |
| B. | <sub>DS</sub> |
| C. | gate source cut off voltage is equal to pinch off voltage |
| D. | gate source cut off voltage is twice the pinch off voltage |
| E. | gate source cut off voltage is equal to negative pinch off voltage |
| Answer» E. gate source cut off voltage is equal to negative pinch off voltage | |
| 4121. |
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. | |
| 4122. |
For a photo conductor with equal electron and hole mobilities and perfect ohmic contacts at the ends, an increase in the intensities of optical illumination results in |
| A. | change in open circuit voltage |
| B. | change in short circuit current |
| C. | a reduction resistance |
| D. | an increase of resistance |
| Answer» D. an increase of resistance | |
| 4123. |
The voltage across the secondary of the transformer in a half wave rectifier (without any filter circuit) is 25 volts. The maximum voltage on the reverse biased diode will be |
| A. | 100 V |
| B. | 50 V |
| C. | 25 V |
| D. | 12.5 V |
| Answer» D. 12.5 V | |
| 4124. |
Figure shows the terminals of a transistor in plastic package TO 18. Then |
| A. | terminals 1, 2, 3 are emitter, collector, base respectively |
| B. | terminals 1, 2, 3 are emitter, base, collector respectively |
| C. | terminals 1, 2, 3 are base, emitter collector, respectively |
| D. | terminals 1, 2, 3 are collector, emitter, base respectively |
| Answer» C. terminals 1, 2, 3 are base, emitter collector, respectively | |
| 4125. |
Fermi level is the maximum energy that an electron can possess at 0 K. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 4126. |
Which of the following insulating material is restricted to temperatures below 100 C? |
| A. | Micanite |
| B. | Asbestos |
| C. | Teflon |
| D. | Polythene |
| Answer» E. | |
| 4127. |
- ve feedback in an amplifier |
| A. | reduces gain |
| B. | increase frequency and phase distortion |
| C. | reduce bandwidth |
| D. | increase noise |
| Answer» B. increase frequency and phase distortion | |
| 4128. |
Gel is |
| A. | a polymer having side groups distributed randomly along a vinly polymer chain |
| B. | a polymer having secondary chains branching from the main molecular chain |
| C. | a solid frame work of colloidal particles linked together and containing a fluid |
| D. | a polymer in which the repeating unit of each molecule has vinyl group |
| Answer» D. a polymer in which the repeating unit of each molecule has vinyl group | |
| 4129. |
When a P-N junction is unbiased, the junction current at equilibrium is |
| A. | zero as no charges cross the junction |
| B. | zero as equal number of carriers cross the barrier |
| C. | mainly due to diffusion of majority carriers |
| D. | mainly due to diffusion of minority carriers |
| Answer» C. mainly due to diffusion of majority carriers | |
| 4130. |
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 | |
| 4131. |
Which one of the following material has the highest dielectric strength? |
| A. | Porcelain |
| B. | Soft rubber |
| C. | Glass |
| D. | polystyrene |
| Answer» C. Glass | |
| 4132. |
How is an N-channel junction Field Effect Transistor operated as an amplifier? |
| A. | With a forward bias gate source junction |
| B. | With a reverse bias gate-source junction |
| C. | With a open gate source junction |
| D. | With a shorted gate source junction |
| Answer» C. With a open gate source junction | |
| 4133. |
Ferrites are |
| A. | hard materials |
| B. | brittle materials |
| C. | not easily machinable |
| D. | materials with all above properties |
| Answer» E. | |
| 4134. |
The merging of a hole and an electron is called |
| A. | recombination |
| B. | covalent bonding |
| C. | thermal union |
| D. | none of the above |
| Answer» B. covalent bonding | |
| 4135. |
Which of the following semiconductor has the highest melting point? |
| A. | Germanium |
| B. | Silicon |
| C. | Gallium arsenide |
| D. | Lead sulphide |
| Answer» E. | |
| 4136. |
The forbidden energy gap in semiconductors |
| A. | is always zero |
| B. | lies just below the valence band |
| C. | lies between the valence band and the conduction band |
| D. | lies just above the conduction band |
| Answer» D. lies just above the conduction band | |
| 4137. |
In a conductor the conduction and valence bands overlap |
| A. | True |
| B. | False |
| Answer» B. False | |
| 4138. |
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. | |
| 4139. |
When a diode is forward biased, the diode current is |
| A. | high |
| B. | low |
| C. | zero |
| D. | low or zero |
| Answer» B. low | |
| 4140. |
At room temperature, the current in the, intrinsic semiconductor is due to |
| A. | holes |
| B. | electrons |
| C. | ions |
| D. | holes and electrons |
| Answer» E. | |
| 4141. |
The dc output voltage from a power supply |
| A. | increases with higher values of filter capacitance and decreases with more load current |
| B. | decreases with higher values of filter capacitance and increases with more load current |
| C. | decreases with higher values of filter capacitance as well as with more load current |
| D. | increases with higher values of filter capacitance as well as with more load current |
| Answer» B. decreases with higher values of filter capacitance and increases with more load current | |
| 4142. |
Which of these is also called 'hot carrier diode'? |
| A. | PIN diode |
| B. | LED |
| C. | Photo diode |
| D. | Schottky diode |
| Answer» E. | |
| 4143. |
A d.c. power supply has an open circuit voltage of 100 V. When the full load current is drawn, the output drops to 80 V. The percentage voltage regulation is |
| A. | 97.25% |
| B. | 75% |
| C. | 50% |
| D. | 25% |
| Answer» E. | |
| 4144. |
Avalanche beakdown is primarily dependent on the phenomenon of |
| A. | doping |
| B. | collision |
| C. | recombination |
| D. | ionization |
| Answer» C. recombination | |
| 4145. |
The electric breakdown strength is affected by |
| A. | shape of the waveform of applied voltage |
| B. | steepness of the wavefront of the applied voltage |
| C. | composition of the material |
| D. | all of the above |
| Answer» E. | |
| 4146. |
The holes diffuse from P-region to the N-region in a P-N junction diode because |
| A. | there is greater concentration of holes in the P-region as compared to N-region |
| B. | there is greater concentration of holes in the N-region as compared to P-region |
| C. | the free electrons in the N-region attract them |
| D. | potential difference facilities such transfer |
| Answer» B. there is greater concentration of holes in the N-region as compared to P-region | |
| 4147. |
Surface leakage current is a part of |
| A. | reverse current |
| B. | forward current |
| C. | reverse breakdown |
| D. | forward breakdown |
| Answer» B. forward current | |
| 4148. |
The small signal input impedance of a transistor whose output is shorted for the measuring signal is |
| A. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/49-298-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/49-298-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/49-298-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/49-298-4.png"> |
| Answer» B. <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/49-298-2.png"> | |
| 4149. |
Assertion (A): The frequency of light used for photoelectric emission is high. Reason (R): As per Einstein's equation 0.5 mv2 < hf - Uw. |
| 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 | |
| 4150. |
What is meant by "continuous collector current" in BJT? |
| A. | Maximum collector current |
| B. | Current at Quiescent condition |
| C. | Leakage current |
| D. | Junction Capacitance charging and discharging current |
| Answer» B. Current at Quiescent condition | |