MCQOPTIONS
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MCQOPTIONS
This section includes 257 Mcqs, each offering curated multiple-choice questions to sharpen your Power Electronics knowledge and support exam preparation. Choose a topic below to get started.
| 201. |
In a thyristor, ratio of latching current to holding current is |
| A. | 0 4 |
| B. | 1 0 |
| C. | 2 5 |
| D. | 6 0 |
| Answer» D. 6 0 | |
| 202. |
Particular location in storage is identified by: |
| A. | Register |
| B. | Counter |
| C. | Address |
| D. | Sector |
| Answer» D. Sector | |
| 203. |
For the SCR, di/dt protection is achieved through the use of |
| A. | R in series with SCR |
| B. | L in series with SCR |
| C. | RL in series with SCR |
| D. | RLC in series with SCR |
| Answer» C. RL in series with SCR | |
| 204. |
An operation in which data is moved to a different location is called: |
| A. | Block move |
| B. | Street move |
| C. | Delete |
| D. | Paste |
| Answer» B. Street move | |
| 205. |
Reverse recovery current in a Diode depends opon |
| A. | Forward field current |
| B. | Storage charge |
| C. | Temperature |
| D. | P/V |
| Answer» B. Storage charge | |
| 206. |
A collection of programs that controls how your computer system runs and proceses information is called: |
| A. | Operating system |
| B. | Complier |
| C. | |
| D. | Interpreter |
| E. | Computer |
| Answer» B. Complier | |
| 207. |
The softness factor for soft recovery and fast recovery Diode are respectively |
| A. | 1, > 1 |
| B. | < 1, 1 |
| C. | 1, 1 |
| D. | 1, < 1 |
| Answer» E. | |
| 208. |
A set of instructions telling the computer what to do is called: |
| A. | Operating system |
| B. | |
| C. | Program |
| D. | Complier |
| E. | Instructor |
| Answer» C. Program | |
| 209. |
Auxiliary storage is: |
| A. | It has an operating speed far slower than the primary storage |
| B. | It has an operating speed faster than that of the primary storage |
| C. | It has an operating speed equivalent than that of the primary storage |
| D. | None of these |
| Answer» B. It has an operating speed faster than that of the primary storage | |
| 210. |
The forward voltage drop during SCR on-state is 1 5 V. This voltage drop |
| A. | remains constant and is independent of load current |
| B. | increases slightly with load current |
| C. | decreases slightly with load current |
| D. | varies linearly with load current |
| Answer» C. decreases slightly with load current | |
| 211. |
The following computer s memory is characterized by low cost per bit stored: |
| A. | Secondary |
| B. | Primary |
| C. | Hard disk |
| D. | All of these |
| Answer» B. Primary | |
| 212. |
When a thyristor gets turned on, the gate drive |
| A. | should not be removed as it will turn-off the SCR |
| B. | may or may not be removed |
| C. | should be removed |
| D. | should be removed in order to avoid increased losses and higher junction temperature |
| Answer» E. | |
| 213. |
A thyristor, when triggered, will change from forward blocking state to conduction state if its anode to cathode voltage is equal to |
| A. | peak repetitive off-state forward voltage |
| B. | peak working off-state forward voltage |
| C. | peak working off-state reverse voltage |
| D. | peak non-repetitive off-state forward voltage |
| Answer» C. peak working off-state reverse voltage | |
| 214. |
In a thyristor, anode current is made up of |
| A. | electrons only |
| B. | electrons or holes |
| C. | electrons and holes |
| D. | holes only |
| Answer» D. holes only | |
| 215. |
A flat, circular plate coated with a magnetic material on which data can be stored by magnetization of portion of the flat surface is: |
| A. | Disk |
| B. | Tape |
| C. | Pen drive |
| D. | None of these |
| Answer» B. Tape | |
| 216. |
During forward blocking state, a thyristor is associated with |
| A. | large current, low voltage |
| B. | low current, large voltage |
| C. | medium current, large voltage |
| D. | low current, medium voltage |
| Answer» C. medium current, large voltage | |
| 217. |
An SCR can be brought to forward conducting state with gate-circuit open when the applied voltage exceeds |
| A. | the forward breakover voltage |
| B. | reverse breakdown voltage |
| C. | 1 5 V |
| D. | peak non-repetitive off-state voltage |
| Answer» B. reverse breakdown voltage | |
| 218. |
A device used to contain a pre recorded program: |
| A. | Cartridge |
| B. | Cache |
| C. | Carrier |
| D. | None of these |
| Answer» B. Cache | |
| 219. |
Cache memory is: |
| A. | Main memory |
| B. | Permanent storage |
| C. | Small buffer storage |
| D. | None of these |
| Answer» D. None of these | |
| 220. |
Bubble memory is: |
| A. | Volatile |
| B. | Non-volatile |
| C. | Permanent |
| D. | None of these |
| Answer» C. Permanent | |
| 221. |
When cathode is positive with respect to anode in an SCR, the number of blocked p-n junctions is |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 222. |
A power Mosfet has three terminals called |
| A. | Collector, emitter and base |
| B. | Drain source and base |
| C. | Drain, source and gate |
| D. | Collector, emitter and gate |
| Answer» D. Collector, emitter and gate | |
| 223. |
A Chopper operating at a fixed frequency is feeding an R L load. As the duty ratio of the chopper is increased from 25% to 75%, the ripple in the load current |
| A. | Remain constant |
| B. | Decreases, reaches a minimum at 50% duty ratio and then increases |
| C. | Increases, reaches a maximum at 50%, duty ratio and then decreases |
| D. | Keeps on increasing as the duty ratio is increased |
| Answer» B. Decreases, reaches a minimum at 50% duty ratio and then increases | |
| 224. |
When a line commutated converter operates in a Inverter mode |
| A. | It draws both real and reactive power from the A.C. supply |
| B. | It delivers both Real and reactive power to the A.C. supply |
| C. | It delivers real power to the A.C. supply |
| D. | It draws reactive power from the A.C. supply |
| Answer» D. It draws reactive power from the A.C. supply | |
| 225. |
A Zener Diode work on the principle of |
| A. | Tunnelling of charge carriers across the junction |
| B. | Thermionic emission |
| C. | Diffusion of charge carrier across the junction |
| D. | hopping of charge carrier across the junction |
| Answer» B. Thermionic emission | |
| 226. |
In a Diode, the cut in voltage and forward-voltage drop are respectively |
| A. | 0.7V, 0.7 V |
| B. | 0.7V, IV |
| C. | 0.7V, 0.6 V |
| D. | IV, 0.7 V |
| Answer» D. IV, 0.7 V | |
| 227. |
For a Diode, Reverse recovery time is defined as the time between the instant Diode current become zero and the instant reverse recovery current decays to |
| A. | Zero |
| B. | 10% of reverse peak current IRM |
| C. | 25% of IRM |
| D. | 15% of IRM |
| Answer» D. 15% of IRM | |
| 228. |
Transformation of input into output is performed by: |
| A. | Memory |
| B. | Storage |
| C. | Input-output unit |
| D. | The CPU |
| Answer» E. | |
| 229. |
When anode is positive with respect to cathode in an SCR, the number of blocked p-n junctions is |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» B. 2 | |
| 230. |
The number of p-n junctions in a thyristor is |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 231. |
When a thyristor is negatively biased |
| A. | All the three functions are negatively biased |
| B. | Quter functions are positively biased and the inner function are negatively biased |
| C. | Quter functions are negatively biased and the inner function are positively biased |
| D. | The function near the Anode is negatively biased and |
| E. | the one near the cathode is positively biased |
| Answer» D. The function near the Anode is negatively biased and | |
| 232. |
In the circuit of given Fig. the diode states at the extremely large negative value of the input voltage v |
| A. | D1 off, D2 off |
| B. | D1 on, D2 off |
| C. | D1 off, D2 on |
| D. | D1 on, D2 on |
| Answer» C. D1 off, D2 on | |
| 233. |
At present, the state of the art devices are available as under MOSFET BJT |
| A. | 1200 V, 800 A 500 V, 140 A |
| B. | 500V, 140 A 1200 V, 800 A |
| C. | 800 V, 1000 A 1000 V, 1200 A |
| D. | 200 V, 140 A 1500 V, 800 A |
| Answer» C. 800 V, 1000 A 1000 V, 1200 A | |
| 234. |
Fig. shows an electronic voltage regulator. The zener diode may be assumed to require a minimum current of 25 mA for satisfactory operation. The value of R required for satisfactory operation is ohm. |
| A. | 80 |
| B. | 40 |
| C. | 20 |
| D. | None of these |
| Answer» B. 40 | |
| 235. |
An IGBT has three terminals called |
| A. | Collector, emitter and base |
| B. | Drain, source and base |
| C. | Drain, source and gate |
| D. | Drain, source and gate |
| Answer» E. | |
| 236. |
13. In the circuit of Fig. the 5V zener diode requires a minimum current of 10 mA. For obtaining a regulated output of 5 V, the maximum permissible load current I |
| A. | 40 mA, 0 05 W |
| B. | 20 mA, 0 05 W |
| C. | 40 mA, 0 5 W |
| D. | 20 mA, 0 5 W |
| Answer» B. 20 mA, 0 05 W | |
| 237. |
The circuit in Fig. shows zener-regulated dc power supply. The zener diode is ideal. The minimum value of R |
| A. | 27 |
| B. | 45 |
| C. | 15 |
| D. | 24 |
| Answer» C. 15 | |
| 238. |
For a symmetrical square wave of 800 V peak to peak and for ideal diode, the voltmeter in Fig. will read |
| A. | 200 V |
| B. | 400 V |
| C. | 800 V |
| D. | zero |
| Answer» B. 400 V | |
| 239. |
An MCT has three terminals called |
| A. | Collector, emitter and gate |
| B. | Anode, cathode and gate |
| C. | Drain, source and base |
| D. | Drain, source and gate |
| Answer» C. Drain, source and base | |
| 240. |
In Fig. V |
| A. | 20 V |
| B. | 20 V |
| C. | 10 V |
| D. | None of these |
| Answer» C. 10 V | |
| 241. |
A single-phase voltage Source square-wave inverter feeds pure Inductive load. The wave form of the load current will be |
| A. | Sinusoidal |
| B. | Rectangular |
| C. | Trapezoidal |
| D. | Triangular |
| Answer» E. | |
| 242. |
The peak current through the resistor of circuit of Fig. assuming the diodes to be ideal, is |
| A. | 12 mA |
| B. | 4 mA |
| C. | 16 mA |
| D. | 8 mA |
| Answer» E. | |
| 243. |
In Fig. ideal moving iron voltmeters M |
| A. | 141 4 V, 141 4 V |
| B. | 0, 141 4 V |
| C. | 0, 200 V |
| D. | 141 4 V, 0 |
| Answer» C. 0, 200 V | |
| 244. |
For the switching waveform shown in fig. for a power transistor the peak instantaneous power loss in watts is |
| A. | 250 |
| B. | 500 |
| C. | 166 67 |
| D. | 333 33 |
| Answer» B. 500 | |
| 245. |
A voltage v = 4 sin t is applied to the terminals A and B of the circuit shown in Fig. The diodes are assumed to be ideal. The impedance offered by the circuit across the terminals A and B in kilo-ohms is |
| A. | 5 |
| B. | 20 |
| C. | 10 |
| D. | None of these |
| Answer» D. None of these | |
| 246. |
A single phase full bridge diode rectifier delivers a constant load current of 10 A. Average and rms values of source current are respectively |
| A. | 5 A, 10 A |
| B. | 10 A, 10 A |
| C. | 5 A, 5 A |
| D. | 0, 10 A |
| Answer» E. | |
| 247. |
Consider the following statements: The Diode in a voltage source inverter (Mc Murry inverter) should be able to |
| A. | 1, 2 and 3 are correct |
| B. | 1, 3 and 4 are correct |
| C. | 2, 3 and 4 are correct |
| D. | 1, 2 and 4 are correct |
| Answer» D. 1, 2 and 4 are correct | |
| 248. |
Consider the following statements regarding speed control of induction motors by means of external rotor resisters: |
| A. | 1 and 3 |
| B. | 2 and 3 |
| C. | 1 and 2 |
| D. | 1, 2 and 3 |
| Answer» B. 2 and 3 | |
| 249. |
For the switching wave form shown in fig. for a power transistor, the average value of switch on power loss at a switching frequency of 10 kHz is |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 250. |
A single phase full bridge diode rectifier delivers a load current of 10 A, which is ripple free. Average and rms values of diode currents are respectively |
| A. | 10 A, 7 07 A |
| B. | 5 A, 10 A |
| C. | 5 A, 7 07 A |
| D. | 7 07 A, 5 A |
| Answer» B. 5 A, 10 A | |