MCQOPTIONS
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MCQOPTIONS
This section includes 1136 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics & Communication Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 251. |
The circuit shown in figure will |
| A. | oscillate at 456 kHz |
| B. | oscillate at 228 kHz |
| C. | oscillate at microwave frequency |
| D. | not oscillate |
| Answer» E. | |
| 252. |
Which of the following circuit has the greatest bandwidth? |
| A. | fr = 455 MHz; Q = 10 |
| B. | fr = 455 MHz; Q = 100 |
| C. | fr = 1 MHz; Q = 100 |
| D. | fr = 1 MHz; Q = 10 |
| Answer» E. | |
| 253. |
A two stage amplifier has an upper cutoff frequency of 2 MHz and a lower cutoff frequency of 2 MHz and a lower cut off frequency of 30 Hz. If both stages are similar, their individual upper and lower cut off frequencies respectively are |
| A. | 4 MHz and 60 MHz |
| B. | 3 MHz and 20 Hz |
| C. | 3 MHz and 60 Hz |
| D. | 4 MHz and 20 Hz |
| Answer» C. 3 MHz and 60 Hz | |
| 254. |
The circuit shown in the figure is that of |
| A. | an oscillator |
| B. | Schmitt trigger |
| C. | differential current |
| D. | emitter current |
| Answer» E. | |
| 255. |
For Q >> 1, the output frequency of LC oscillator is equal to resonant frequency. |
| A. | 1 |
| B. | |
| C. | diode A is forward biased and diode B is reverse biased |
| D. | both diodes are reverse biased |
| Answer» B. | |
| 256. |
In a two stage CE amplifier circuit, the ac collector resistance of the first stage depends on |
| A. | load resistance |
| B. | input impedance of first stage |
| C. | input impedance of second stage |
| D. | all of the above |
| Answer» D. all of the above | |
| 257. |
A Wien bridge oscillator uses Wien bridge for |
| A. | tuning and phase shift |
| B. | tuning |
| C. | phase shift |
| D. | either tuning or phase shift |
| Answer» B. tuning | |
| 258. |
For the circuit shown in the figure, the capacitor C is initially uncharged. At t = 0, the switch S is closed. The voltage Vc across the capacitor at t = 1 millisecond is (In the figure shown above, the op-amp is supplied with ± 15 V and the ground has been shown by the symbol) |
| A. | 0 V |
| B. | 6.3 V |
| C. | 9.45 volts |
| D. | 10 volts |
| Answer» E. | |
| 259. |
The coupling capacitor in amplifier circuits |
| A. | affects dc biasing |
| B. | does not affect dc biasing |
| C. | affects dc biasing to some extent |
| D. | both (a) and (c) |
| Answer» C. affects dc biasing to some extent | |
| 260. |
In graphical analysis of BJT amplifier the slope of ac line is more than that of dc load line. |
| A. | 1 |
| B. | |
| C. | CC |
| D. | CE |
| Answer» B. | |
| 261. |
Which connection is rarely used? |
| A. | CE |
| B. | CB |
| C. | CC |
| D. | Both (a) and (b) |
| Answer» C. CC | |
| 262. |
A bypass capacitor produces |
| A. | both dc and ac ground |
| B. | none of the above |
| C. | 10% of its final value to 90% of its final value |
| D. | 0% of its final value to 90% of its final value |
| Answer» C. 10% of its final value to 90% of its final value | |
| 263. |
A Weinbridge oscillator is a |
| A. | VHF oscillator |
| B. | RF oscillator |
| C. | microwave oscillator |
| D. | audio frequency oscillator |
| Answer» E. | |
| 264. |
Stability factor for S is given by for a fixed bias |
| A. | 1 + β |
| B. | 1 - β |
| C. | 1/β |
| D. | β - 1 |
| Answer» B. 1 - Œ≤ | |
| 265. |
A push pull amplifier balance out |
| A. | odd harmonics |
| B. | even harmonics |
| C. | both odd as well as even harmonics |
| D. | neither odd nor even harmonics |
| Answer» B. even harmonics | |
| 266. |
In a push pull circuit |
| A. | each transistor conducts for less than 180° |
| B. | the period of conduction of each transistor depends on circuit configuration |
| C. | 5.15 mA |
| D. | 5.2 mA |
| Answer» B. the period of conduction of each transistor depends on circuit configuration | |
| 267. |
Occasionally a discrete amplifier user RF chokes instead of collector resistors. Such amplifiers are inherently |
| A. | low pass amplifiers |
| B. | high pass amplifiers |
| C. | band pass amplifiers |
| D. | none of the above |
| Answer» C. band pass amplifiers | |
| 268. |
Assertion (A): Electric coupling, magnetic coupling and ground loop can cause unwanted high frequency oscillations.Reason (R): Hartley oscillator uses a tapped inductor |
| A. | Both A and R are correct and R is correct explanation for A |
| B. | Both A and R are correct but R is not correct explanation for A |
| C. | A is correct R is wrong |
| D. | A is wrong R is correct |
| Answer» C. A is correct R is wrong | |
| 269. |
In an op-amp differentiator |
| A. | the amplitude of output is proportional to rate of change of input |
| B. | the amplitude of output is proportional to input |
| C. | output occurs when input is finite and constant |
| D. | polarity of input and output is the same |
| Answer» B. the amplitude of output is proportional to input | |
| 270. |
If a capacitor C is charged by a constant current I, then the rate of change of voltage with time given by sweep speed equal to |
| A. | C/I |
| B. | IC |
| C. | I/C |
| Answer» D. | |
| 271. |
Calculate the conductivity of pure silicon at room temperature when the concentration of carriers is 1.6 x 1010 per cm3. Take μe = 1500 cm2/V-sec, μh = 500 cm2/V-sec at room temperature, |
| A. | 5.12 x 10-16 |
| B. | 5 x 10+16 |
| C. | 1016 |
| D. | 5 x 1020 |
| Answer» B. 5 x 10+16 | |
| 272. |
Find the odd one out |
| A. | sweep voltage generator |
| B. | multivibrators |
| C. | sine wave oscillators |
| D. | blocking oscillators |
| Answer» D. blocking oscillators | |
| 273. |
A logarithmic amplifier has diode in the feedback path. |
| A. | 1 |
| B. | |
| C. | infinitely high |
| D. | around 1 kΩ |
| Answer» B. | |
| 274. |
With JFETs cascade means |
| A. | a common source driving a common gate connection |
| B. | a common gate driving a common source connection |
| C. | two FETs connected in parallel |
| D. | none of the above |
| Answer» B. a common gate driving a common source connection | |
| 275. |
At high frequencies the output circuit of transistor amplifier reduces to |
| A. | a lead network |
| B. | a lag network |
| C. | either (a) or (b) |
| D. | neither (a) nor (b) |
| Answer» C. either (a) or (b) | |
| 276. |
In Class C operation the collector current looks like |
| A. | full sine wave |
| B. | half sine wave |
| C. | narrow pulses |
| D. | nearly half sine wave |
| Answer» D. nearly half sine wave | |
| 277. |
The symbol shown in figure represents a |
| A. | P-channel MOSFET |
| B. | UJT with N-type base |
| C. | N-channel DEMOSFET with internal zener protection |
| D. | P-channel DEMOSFET with internal zener protection |
| Answer» D. P-channel DEMOSFET with internal zener protection | |
| 278. |
Negative feedback lowers the cut off frequency and increase the upper cut off frequency of amplifier. |
| A. | 1 |
| B. | |
| C. | zero |
| D. | 135° |
| Answer» B. | |
| 279. |
The h parameter h11 is the same in CE and CC circuit. |
| A. | 1 |
| B. | |
| C. | fOH > fOL |
| D. | fOH < fOL |
| Answer» B. | |
| 280. |
A junction Field Effect Transistor can operate in |
| A. | depletion mode only |
| B. | enhancement mode only |
| C. | depletion and enhancement modes |
| D. | neither depletion nor enhancement modes |
| Answer» B. enhancement mode only | |
| 281. |
Which of the following combinations has no phase inversion of the signal? |
| A. | Three CE stages |
| B. | CE stages and emitter follower |
| C. | hie |
| D. | hre |
| Answer» B. CE stages and emitter follower | |
| 282. |
An op-amp has zero gain for common mode inputs. Then CMRR = |
| A. | zero |
| B. | infinite |
| C. | high |
| D. | low |
| Answer» C. high | |
| 283. |
The horizontal intercept of dc load line is the same as ideal |
| A. | cut off point |
| B. | saturation point |
| C. | operating point |
| D. | quasi saturation point |
| Answer» B. saturation point | |
| 284. |
In figure the approximate voltages of |
| A. | base and emitter are - 8 V and - 7.3 V |
| B. | base and collector are - 8 V and - 5 V |
| C. | collector and emitter are - 5 V and - 7.3 V |
| D. | base, emitter and collector are - 8, - 7.3 and - 5 V |
| Answer» B. base and collector are - 8 V and - 5 V | |
| 285. |
The circuit shown I/P in the figure represents |
| A. | Low pass filter |
| B. | High pass filter |
| C. | Band Pass filter |
| D. | Band stop filter |
| Answer» D. Band stop filter | |
| 286. |
Figure shows a self bias circuit for FET amplifier, ID = 4 mA. Then IS = |
| A. | 0.4 mA |
| B. | 0.2 mA |
| C. | 200 |
| D. | 40 |
| Answer» B. 0.2 mA | |
| 287. |
The voltage gain of which transistor configuration is less than unity? |
| A. | CC |
| B. | None |
| C. | saturation region |
| D. | cut off region |
| Answer» D. cut off region | |
| 288. |
A bridge rectifier circuit has a dc load current of 10 mA and a filter capacitance of 1000 μF. The peak to peak ripple voltage is |
| A. | 0.01 V |
| B. | 0.05 V |
| C. | 0.1 V |
| D. | 0.5 V |
| Answer» D. 0.5 V | |
| 289. |
When the circuit is switched on, the loop gain of a Wien bridge oscillator is |
| A. | 1 |
| B. | more than 1 |
| C. | less than 1 |
| D. | about 0.5 |
| Answer» C. less than 1 | |
| 290. |
In figure, ID = 4 mA. Then VD = |
| A. | 30 V |
| B. | 1 V |
| C. | amplifier circuits |
| D. | oscillator circuits |
| Answer» C. amplifier circuits | |
| 291. |
The advantage of transistor over vacuum tube is |
| A. | no heat is required |
| B. | small size and light in weight |
| C. | very low power consumption |
| D. | all of the above |
| Answer» E. | |
| 292. |
In the above case, what will be the value of capacitor to obtain 100 kHz frequency? |
| A. | 0.0065 pF |
| B. | 0.0130 pF |
| C. | 0.0260 pF |
| D. | 0.520 pF |
| Answer» B. 0.0130 pF | |
| 293. |
If a class C power amplifier has an input signal with frequency of 200 kHz and the width of collector current pulses of 0.1 ms, then the duty cycle of the amplifier will be |
| A. | 0.01 |
| B. | 0.02 |
| C. | 0.1 |
| D. | 0.2 |
| Answer» E. | |
| 294. |
In a linear op-amp circuit |
| A. | the product of gain and bandwidth is constant |
| B. | input can be dc only |
| C. | input can be ac only |
| D. | saturation may occur |
| Answer» B. input can be dc only | |
| 295. |
The current ICBO |
| A. | increases with increases in temperature |
| B. | is normally greater for silicon transistor than germanium transistors |
| C. | mainly depends on the emitter base junction bias |
| D. | depends largely on the emitter doping |
| Answer» B. is normally greater for silicon transistor than germanium transistors | |
| 296. |
In a single stage differential amplifier, the output offset voltage is basically dependent on the mismatch of |
| A. | VBE, IB and β |
| B. | VBE and IB |
| C. | IB and β |
| D. | VBE and β |
| Answer» D. VBE and Œ≤ | |
| 297. |
In a rectifier circuit the filter capacitance is increased. Then the ripple will |
| A. | increase |
| B. | decrease |
| C. | remain the same |
| D. | either (a) or (b) |
| Answer» C. remain the same | |
| 298. |
The input to an op-amp integrating amplifier is a constant voltage. The output will be |
| A. | a constant voltage |
| B. | a sawtooth wave |
| C. | a ramp |
| D. | ac voltage |
| Answer» E. | |
| 299. |
The Darlington pair consists of the following two stages |
| A. | both CC |
| B. | CE and CB |
| C. | Adder |
| D. | Multiplier |
| Answer» D. Multiplier | |
| 300. |
For an amplifier the power gain in decibels will be equal to voltage gain in decibels only when |
| A. | R0 = 0 |
| B. | R0 = Ri = 90 |
| C. | R0 = Ri |
| D. | Ri = 0 |
| Answer» D. Ri = 0 | |