MCQOPTIONS
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MCQOPTIONS
This section includes 223 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics knowledge and support exam preparation. Choose a topic below to get started.
| 201. |
What is the current through the load in the given circuit? |
| A. | 500 A |
| B. | 10 mA |
| C. | 250 mA |
| D. | 1.25 A |
| Answer» D. 1.25 A | |
| 202. |
The secondary current is _____ in the given circuit. |
| A. | 1.9 mA |
| B. | 7.5 mA |
| C. | 30 mA |
| D. | 60 mA |
| Answer» D. 60 mA | |
| 203. |
If the load doubled in value in the given circuit, what reflected resistance would the source see? |
| A. | 80 |
| B. | 400 |
| C. | 2 k |
| D. | 10 k |
| Answer» B. 400 | |
| 204. |
The secondary voltages produced by a center-tapped transformer are equal in amplitude but 180° out of phase with respect to the center tap. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 205. |
___ occurs in a transformer when some of the primary flux lines pass through the air instead of the core. |
| A. | Hysteresis loss |
| B. | Magnetic flux leakage |
| C. | Winding resistance |
| D. | Winding capacitance |
| Answer» C. Winding resistance | |
| 206. |
In the given circuit, the secondary voltage is in phase with the primary voltage. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 207. |
A transformer turns ratio of ________ will be needed to match an output impedance of 5 k to an 8 speaker. |
| A. | 0.20902777777778 |
| B. | 0.33402777777778 |
| C. | 1.0423611111111 |
| D. | 26.042361111111 |
| Answer» D. 26.042361111111 | |
| 208. |
The transformer turns ratio determines |
| A. | the ratio of primary and secondary voltages |
| B. | the ratio of primary and secondary currents |
| C. | the reflected impedance |
| D. | all of the above |
| Answer» E. | |
| 209. |
A transformer has |
| A. | primary and secondary windings, both of which are considered inputs |
| B. | primary and secondary windings, both of which are considered outputs |
| C. | a primary winding used as an output and a secondary winding used as an input |
| D. | a primary winding used as an input and a secondary winding used as an output |
| Answer» E. | |
| 210. |
A transformer that has 700 turns in the primary and 35 turns in the secondary has a turns ratio of 20:1. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» B. | |
| 211. |
Making the load resistance appear the same as the source's internal resistance is called _____. |
| A. | maximum power transfer |
| B. | reflected resistance |
| C. | impedance matching |
| D. | reflected load |
| Answer» D. reflected load | |
| 212. |
The reflected load value that the source sees will always be larger than the load value itself. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 213. |
Mutual induction is dependent on |
| A. | winding ratios |
| B. | output polarities |
| C. | dc voltage levels |
| D. | current changes |
| Answer» E. | |
| 214. |
What is the power dissipated in the primary of the transformer in the given circuit? |
| A. | 25 mW |
| B. | 500 mW |
| C. | 12.5 W |
| D. | 62.5 W |
| Answer» E. | |
| 215. |
What is the secondary voltage in the given circuit? |
| A. | 13.3 V rms in phase with the primary |
| B. | 120 V rms in phase with the primary |
| C. | 13.3 V rms out of phase with the primary |
| D. | 120 V rms out of phase with the primary |
| Answer» D. 120 V rms out of phase with the primary | |
| 216. |
Increasing the number of turns of wire on the secondary of a transformer will |
| A. | increase the secondary current |
| B. | decrease the secondary current |
| C. | have no effect on the secondary current |
| D. | increase the primary current |
| Answer» C. have no effect on the secondary current | |
| 217. |
A transformer is plugged into a 120 V rms source and has a primary current of 300 mA rms. The secondary is providing 18 V across a 10 load. What is the efficiency of the transformer? |
| A. | 0.88 |
| B. | 0.9 |
| C. | 0.92 |
| D. | 0.95 |
| Answer» C. 0.92 | |
| 218. |
To ensure a high coefficient of coupling, all fixed transformers are usually wound on a(n) _____________. |
| A. | EI core |
| B. | iron core |
| C. | common core |
| D. | CI core |
| Answer» D. CI core | |
| 219. |
What is the turns ratio of the transformer needed to match a 1 k source resistance to a 160 load? |
| A. | 2.5:1 |
| B. | 0.4:1 |
| C. | 6.25:1 |
| D. | 0.66736111111111 |
| Answer» C. 6.25:1 | |
| 220. |
The coefficient of coupling between two coils is 0.45. The first coil has an inductance of 75 mH and the second coil has an inductance of 105 mH. What is the mutual inductance between the coils? |
| A. | 3.54 mH |
| B. | 7.88 mH |
| C. | 39.9 mH |
| D. | 189.3 mH |
| Answer» D. 189.3 mH | |
| 221. |
A special transformer used to convert unbalanced signals to balanced signals is the |
| A. | balun |
| B. | autotransformer |
| C. | center-tapped transformer |
| D. | step-across transformer |
| Answer» B. autotransformer | |
| 222. |
If voltage is stepped-up to the secondary, current will be stepped-down by the same amount. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» B. | |
| 223. |
When does maximum power transfer happen from the source to the load? |
| A. | When the source resistance is greater than the load resistance |
| B. | When the source resistance is less than the load resistance |
| C. | When there is negligible source resistance |
| D. | When the source resistance equals the load resistance |
| Answer» E. | |