MCQOPTIONS
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MCQOPTIONS
This section includes 1728 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
Since diodes are destroyed by excessive current, circuits must have: |
| A. | higher voltage sources |
| B. | current limiting resistors |
| C. | more dopants |
| D. | higher current sources |
| Answer» C. more dopants | |
| 152. |
When matching polarity connections have been made and the potential difference (PD) is above 0.7 V, the diode is considered to be: |
| A. | not working |
| B. | forward biased |
| C. | reverse biased |
| D. | an open switch |
| Answer» C. reverse biased | |
| 153. |
In a power supply diagram, which block indicates a smooth dc output? |
| A. | transformer |
| B. | filter |
| C. | rectifier |
| D. | regulator |
| Answer» E. | |
| 154. |
In a diode schematic, the anode is represented by a(n): |
| A. | triangle |
| B. | vertical line |
| C. | zig-zag line |
| D. | element indicator |
| Answer» B. vertical line | |
| 155. |
An IC regulator receives an overload; it will: |
| A. | shut down |
| B. | compensate for heat |
| C. | provide more voltage |
| D. | sample and adjust |
| Answer» B. compensate for heat | |
| 156. |
An ideal operational amplifier has |
| A. | infinite output impedance |
| B. | zero input impedance |
| C. | infinite bandwidth |
| D. | All of the above |
| Answer» D. All of the above | |
| 157. |
Another name for a unity gain amplifier is: |
| A. | difference amplifier |
| B. | comparator |
| C. | single ended |
| D. | voltage follower |
| Answer» E. | |
| 158. |
The open-loop voltage gain (Aol) of an op-amp is the |
| A. | external voltage gain the device is capable of |
| B. | internal voltage gain the device is capable of |
| C. | most controlled parameter |
| D. | same as |
| E. | <i>A<sub>cl</sub></i> |
| Answer» C. most controlled parameter | |
| 159. |
What is the output waveform? |
| A. | sine wave |
| B. | square wave |
| C. | sawtooth wave |
| D. | triangle wave |
| Answer» E. | |
| 160. |
A series dissipative regulator is an example of a: |
| A. | linear regulator |
| B. | switching regulator |
| C. | shunt regulator |
| D. | dc-to-dc converter |
| Answer» B. switching regulator | |
| 161. |
Which type of transformer is required to create a 180 degree input to a rectifier? |
| A. | center-tapped secondary |
| B. | step-down secondary |
| C. | stepped-up secondary |
| D. | split winding primary |
| Answer» B. step-down secondary | |
| 162. |
What circuit activity may shift a characteristic curve so that diode operating points are different? |
| A. | higher power (heat) |
| B. | higher resistance |
| C. | lower voltage |
| D. | lower current |
| Answer» B. higher resistance | |
| 163. |
What is wrong with this diode? |
| A. | open |
| B. | short |
| C. | nothing |
| D. | not enough data |
| Answer» D. not enough data | |
| 164. |
The dc current through each diode in a bridge rectifier equals: |
| A. | the load current |
| B. | half the dc load current |
| C. | twice the dc load current |
| D. | one-fourth the dc load current |
| Answer» B. half the dc load current | |
| 165. |
When a load is not connected to the secondary of a transformer: |
| A. | primary current is zero |
| B. | primary current is inversely proportional to primary impedance |
| C. | secondary voltage is zero |
| D. | secondary voltage is proportional to primary impedance |
| Answer» C. secondary voltage is zero | |
| 166. |
What is the total inductance assuming no mutual inductance? |
| A. | 0 mH |
| B. | 0.69 mH |
| C. | 12 mH |
| D. | 24 mH |
| Answer» C. 12 mH | |
| 167. |
A voltage is induced in a transformer secondary winding by the action of the: |
| A. | secondary magnetic field |
| B. | primary turns ratio |
| C. | primary magnetic field |
| D. | secondary counter emf |
| Answer» D. secondary counter emf | |
| 168. |
What is electromagnetism? |
| A. | the magnetic field generated around a conductor when a current passes through it |
| B. | the magnetic field generated in a conductor by an external voltage |
| C. | the voltage caused by a magnetic field in a conductor |
| D. | the current generated by an external magnetic field |
| Answer» B. the magnetic field generated in a conductor by an external voltage | |
| 169. |
Counter emf or induced voltage is: |
| A. | inversely proportional to the change in current |
| B. | directly proportional to the change in time |
| C. | directly proportional to the inductance in henrys |
| D. | inversely proportional to the inductance in henrys |
| Answer» D. inversely proportional to the inductance in henrys | |
| 170. |
What are the properties that determine the inductance of a coil? |
| A. | Length of wire, number of turns, type of core material, length of core |
| B. | Number of turns, type of wire, length of core, and cross-sectional area of core |
| C. | Type of core material, number of turns, cross-sectional area of core, and length of core |
| D. | Type of core material, type of wire, number of turns, and cross-sectional area of core |
| Answer» D. Type of core material, type of wire, number of turns, and cross-sectional area of core | |
| 171. |
The time required for one weber of flux to cut a conductor and produce one volt is: |
| A. | one revolution |
| B. | one second |
| C. | one millisecond |
| D. | four revolutions |
| Answer» C. one millisecond | |
| 172. |
An inductor is in series with a voltage source, an open switch, and a resistor. The instant the switch is closed, the inductor acts like |
| A. | a short |
| B. | an open |
| C. | a resistor |
| D. | a voltage source |
| Answer» C. a resistor | |
| 173. |
What is the phase angle between the source voltage and current, when a 100 mH inductor with a reactance of 6 k, and a 1 k resistor are in series with a source? |
| A. | 0.1 degrees |
| B. | 9.0 degrees |
| C. | 61.0 degrees |
| D. | 81.0 degrees |
| Answer» E. | |
| 174. |
A practical inductor |
| A. | has inductance |
| B. | has winding resistance |
| C. | has winding capacitance |
| D. | all of the above |
| Answer» E. | |
| 175. |
Fixed transformers have: |
| A. | a center-tapped secondary |
| B. | multiple windings |
| C. | turns ratios that cannot be changed |
| D. | a multiple-tapped secondary |
| Answer» D. a multiple-tapped secondary | |
| 176. |
In a B-H curve, magnetizing force is equal to: |
| A. | <img src="/_files/images/basic-electronics/complete/mcq8_1001_1.gif" alt="mcq8_1001_1.gif" align="absmiddle"> |
| B. | H = I N |
| C. | ampere-turns per weber |
| D. | webers per square meter |
| Answer» B. H = I N | |
| 177. |
Which of the following represents a true equivalent of an inductor? |
| A. | An inductance in series with a resistance and a capacitance |
| B. | A capacitance in parallel with the series combination of a resistance and an inductance |
| C. | An inductance in parallel with the series combination of a resistance and a capacitance |
| D. | The only quality a real inductor has is inductance. |
| Answer» C. An inductance in parallel with the series combination of a resistance and a capacitance | |
| 178. |
What is the maximum source current for a transformer rated at 10 kVA, 1000/500 60 Hz? |
| A. | 2 A |
| B. | 5 A |
| C. | 10 A |
| D. | 20 A |
| Answer» E. | |
| 179. |
The unit of flux density is: |
| A. | magnetomotive force |
| B. | a weber |
| C. | a maxwell |
| D. | a tesla |
| Answer» E. | |
| 180. |
When used as a filter, an inductor is |
| A. | placed in series with the load and aids any current changes |
| B. | placed in parallel with the load and aids any current changes |
| C. | placed in parallel with the load and opposes any current changes |
| D. | placed in series with the load and opposes any current changes |
| Answer» E. | |
| 181. |
A loaded transformer will achieve mutual induction when: |
| A. | secondary current increase causes a primary current decrease |
| B. | primary current is increased by an increase in secondary current |
| C. | primary current is decreased by an increase in secondary current |
| D. | secondary current decrease causes a primary current increase |
| Answer» C. primary current is decreased by an increase in secondary current | |
| 182. |
Which transformer turns ratio is needed to match two 16-ohm parallel devices to an output of 22.2 ohms? |
| A. | 1.38:1 |
| B. | 1.67:1 |
| C. | 0.72:1 |
| D. | 0.60:1 |
| Answer» E. | |
| 183. |
A transformer will have: |
| A. | primary and secondary windings |
| B. | primary and secondary current |
| C. | primary wattage producing secondary current |
| D. | different frequencies for the primary and secondary |
| Answer» B. primary and secondary current | |
| 184. |
What is the phase angle of a 24 Vac parallel RL circuit when R = 45 ohms and XL = 1100 ohms? |
| A. | 0.001 degrees |
| B. | 2.300 degrees |
| C. | 87.600 degrees |
| D. | 89.900 degrees |
| Answer» C. 87.600 degrees | |
| 185. |
A winding of wire can be called |
| A. | an inductor |
| B. | a coil |
| C. | a choke |
| D. | All of the above |
| Answer» E. | |
| 186. |
A value of "ten to the eighth power magnetic lines of force" is for the term: |
| A. | field |
| B. | flux |
| C. | coulomb |
| D. | weber |
| Answer» E. | |
| 187. |
A change of one ampere per second in an inductor that induces a voltage of one volt is considered as which unit value? |
| A. | a lenz |
| B. | an ohm |
| C. | a farad |
| D. | a henry |
| Answer» E. | |
| 188. |
What is the name of the part inside a relay that is moved by the action of the electromagnet? |
| A. | armature |
| B. | conductor |
| C. | contacts |
| D. | solenoid |
| Answer» B. conductor | |
| 189. |
The polarity of induced voltage while a field is collapsing is: |
| A. | independent of the force creating it |
| B. | opposite to the force creating it |
| C. | identical to the force creating the field |
| D. | present only if the force is stationary |
| Answer» C. identical to the force creating the field | |
| 190. |
What is the permeability of transformer iron? |
| A. | 50 |
| B. | 450 |
| C. | 1,500 |
| D. | 5,500 |
| Answer» E. | |
| 191. |
What is the current rise after 2 time constants if Vs = 12 V dc, R = 60 , and the inductor is rated at 24 mH? |
| A. | 79.9 mA |
| B. | 126.4 mA |
| C. | 173.0 mA |
| D. | 198.6 mA |
| Answer» D. 198.6 mA | |
| 192. |
What is the total inductance of a 5 H and a 100 mH coil connected in parallel? |
| A. | 4.76 mH |
| B. | 33.3 mH |
| C. | 98.0 mH |
| D. | 150.0 mH |
| Answer» D. 150.0 mH | |
| 193. |
A transformer is used: |
| A. | to couple electric energy from one dc circuit to another |
| B. | to couple electric energy from an ac circuit to a dc circuit |
| C. | to couple electric energy from a dc circuit to an ac circuit |
| D. | to couple electric energy from one ac circuit to another |
| Answer» E. | |
| 194. |
Which of the following is NOT one of the three major types of fixed inductor? |
| A. | air core |
| B. | ferrite core |
| C. | magnesium core |
| D. | iron core |
| Answer» D. iron core | |
| 195. |
What is the impedance of a 1 kHz series RL circuit when R and XL are both 1000 ohms? |
| A. | 500 ohms |
| B. | 1000 ohms |
| C. | 1414 ohms |
| D. | 2000 ohms |
| Answer» D. 2000 ohms | |
| 196. |
What is remanence? |
| A. | reactance |
| B. | reluctance |
| C. | retentitivity |
| D. | resistance |
| Answer» D. resistance | |
| 197. |
When an electromagnet reaches maximum strength, it is considered to be: |
| A. | in field condition |
| B. | at saturation |
| C. | inhibited |
| D. | at field strength |
| Answer» C. inhibited | |
| 198. |
If you wanted to decrease the inductance of a coil, you might increase the: |
| A. | number of turns |
| B. | permeability of the core |
| C. | spacing between turns |
| D. | area of the coil |
| Answer» D. area of the coil | |
| 199. |
The output phase for a transformer is: |
| A. | in phase with the input |
| B. | out of phase with the input |
| C. | dependent on the direction of the primary and secondary windings |
| D. | dependent on the frequency of the primary source |
| Answer» D. dependent on the frequency of the primary source | |
| 200. |
Opposition to current flow without the dissipation of energy is called: |
| A. | resistance |
| B. | inductive reactance |
| C. | counter emf |
| D. | impedance |
| Answer» C. counter emf | |