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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.
| 6601. |
In radio receiver, the maximum contribution to noise is from |
| A. | mixer stage |
| B. | power supply |
| C. | power amplifier |
| D. | equally from above three |
| Answer» D. equally from above three | |
| 6602. |
Power spectral density of white noise |
| A. | is constant with frequency |
| B. | increases with frequency |
| C. | decreases with frequency |
| D. | none |
| Answer» B. increases with frequency | |
| 6603. |
A receiver having poor IF selectivity will also have poor |
| A. | sensitivity |
| B. | double spotting |
| C. | blocking |
| D. | all of the above |
| Answer» D. all of the above | |
| 6604. |
Statement 1Diode is the most common device used for demodulation.Statement 2A discriminator is a FM detector. |
| A. | Statement 1 is true but statement 2 is false |
| B. | Statement 1 is false but statement 2 is true |
| C. | Both the statements are true |
| D. | Both the statements are false |
| Answer» D. Both the statements are false | |
| 6605. |
Three point tracking can be achieved with |
| A. | gang condenser |
| B. | variable selectivity |
| C. | paddar capacitor |
| D. | any of the above |
| Answer» C. paddar capacitor | |
| 6606. |
Vividh Bharati programme is transmitted in |
| A. | short wave |
| B. | medium frequency |
| C. | very high frequency |
| D. | all of the above |
| Answer» C. very high frequency | |
| 6607. |
The purpose of incorporating a pre-selector stage in a receiver is to |
| A. | provide higher selectivity |
| B. | provide higher fidelity |
| C. | improve linearity |
| D. | larger passband |
| Answer» B. provide higher fidelity | |
| 6608. |
A low ratio of the A.C. load impedance of a diode detector results in |
| A. | diagonal clipping |
| B. | poor AGC operation |
| C. | poor AF response |
| D. | negative peak clipping |
| Answer» E. | |
| 6609. |
A trimmer is basically a |
| A. | insulator |
| B. | inductor |
| C. | capacitor |
| D. | variable resistor |
| Answer» D. variable resistor | |
| 6610. |
Noise limiter is provided on AM receivers to |
| A. | reduce interfering noise due to ignition system |
| B. | reduce noise due to electrical storms |
| C. | reduce interference due to electrical machinery |
| D. | all of the above |
| Answer» E. | |
| 6611. |
In a radio receiver |
| A. | all stages contribute equally to noise |
| B. | RF stage has no effect on S/N ratio |
| C. | mixer stage contributes most of the noise generated |
| Answer» D. | |
| 6612. |
Which curve represents the fidelity curve of a standard receiver? |
| A. | Curve A |
| B. | Curve B |
| C. | Curve C |
| D. | Curve D |
| Answer» D. Curve D | |
| 6613. |
In control systems the word controller includes |
| A. | error detector and feedback element |
| B. | feedback element and control elements |
| C. | error detector and control elements |
| D. | error detector, control elements and feedback elements |
| Answer» D. error detector, control elements and feedback elements | |
| 6614. |
If damping ratio is 0.5, the lines joining complex poles with origin are inclined to negative real axis at |
| A. | 90 |
| B. | 60 |
| C. | 45 |
| D. | 30 |
| Answer» C. 45 | |
| 6615. |
Assertion (A): If points at infinity are included, G(s) has same number of poles and zeros.Reason (R): The function has a zero at s = - 2. |
| A. | Both A and R are correct and R is correct explanation of A |
| B. | Both A and R are correct but R is not correct explanation of A |
| C. | A is correct but R is wrong |
| D. | R is correct but A is wrong |
| Answer» C. A is correct but R is wrong | |
| 6616. |
Integral control action |
| A. | removes offset |
| B. | may lead to oscillatory response |
| C. | both (a) and (b) |
| D. | neither (a) nor (b) |
| Answer» D. neither (a) nor (b) | |
| 6617. |
Nyquist stability criterion uses open loop frequency response characteristics. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 6618. |
Which of the following can act as error detecting devices a pair of potentiometersa pair of synchrosa differential transformera metadynea control transformer Select the answer using the following codes: |
| A. | 1, 2, 5 |
| B. | 2, 3, 4, 5 |
| C. | 1, 3, 4, 5 |
| D. | 1, 2, 3, 4 |
| Answer» B. 2, 3, 4, 5 | |
| 6619. |
A conditionally stable system is stable for the value of gain between two critical values. It is unstable if |
| A. | the gain is increased beyond upper critical value |
| B. | the gain is decreased below lower critical value |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» D. none of the above | |
| 6620. |
Pick the odd one |
| A. | variance |
| B. | standard deviation |
| C. | expectation |
| D. | chebyshev inequality |
| Answer» E. | |
| 6621. |
If the poles of H(z) are at |
| A. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/09-113-1.png"> |
| B. | z = 1 and z = 3 |
| C. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/09-113-3.png"> |
| D. | z = -1 and z = -3 |
| Answer» B. z = 1 and z = 3 | |
| 6622. |
A linear system is characterized by H( ) = Be-2 2 the system is physically |
| A. | unrealizable |
| B. | realizable |
| C. | depends upon B |
| D. | depends upon constant 2 |
| Answer» B. realizable | |
| 6623. |
Consider the following sets of values of E, R and C for the circuit in the given figure. 2 V, 1 , 1.25 F1.6 V, 0.8 , 1 F1.6 V, 1 , 0.8 F2 V, 1.25 , 1 F Which of these of values will ensure that the state equation is valid? |
| A. | 1 and 4 |
| B. | 1 and 2 |
| C. | 3 and 4 |
| D. | 2 and 3 |
| Answer» E. | |
| 6624. |
Half wave sysmmetry means f(t) = - f(t T/2). |
| A. | True |
| B. | False |
| Answer» B. False | |
| 6625. |
The z-transform of sequence x[n] = (n) is |
| A. | 1 |
| B. | |
| C. | 0 |
| D. | <i>z</i> |
| Answer» B. | |
| 6626. |
If xk = 2k for k 0 and xk = 0 for k 0, Z transform of the sequence x is |
| A. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/08-104-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/08-104-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/08-105-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/08-105-4.png"> |
| Answer» E. | |
| 6627. |
If f(t) is an odd function |
| A. | True |
| B. | False |
| Answer» C. | |
| 6628. |
If xk = ak and k 0X(z) = (1 - az-1)-1 with |a| < |z| |
| A. | True |
| B. | False |
| Answer» C. | |
| 6629. |
The function sinc x is equal to |
| A. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/09-115-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/09-115-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/09-115-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/09-115-4.png"> |
| Answer» B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/09-115-2.png"> | |
| 6630. |
The following table gives some time functions and the Laplace transformsOf these correctly matched pairs are |
| A. | 2 and 4 |
| B. | 1 and 4 |
| C. | 3 and 4 |
| D. | 1 and 2 |
| Answer» B. 1 and 4 | |
| 6631. |
In a superheterodyne receiver with an IF of 450 kHz is tuned to a signal at 1200 kHz. The image frequency is |
| A. | 750 kHz |
| B. | 990 kHz |
| C. | 1650 kHz |
| D. | 2100 kHz |
| Answer» E. | |
| 6632. |
As compared to tuned radio frequency receivers which of the following is the advantage of using superheterodyne receivers? |
| A. | High gain and better sensitivity |
| B. | Better selectivity at high frequencies |
| C. | Stability |
| D. | Noise suppression |
| Answer» B. Better selectivity at high frequencies | |
| 6633. |
Which of the following should be used in order to prevent overloading or the last IF amplifier in a receiver? |
| A. | Variable selectivity |
| B. | Variable sensitivity |
| C. | Double conversion |
| D. | Squelch |
| Answer» C. Double conversion | |
| 6634. |
A heterodyne frequency changer is called a |
| A. | Modulator |
| B. | Mixer |
| C. | Demodulator |
| D. | Frequency translator |
| Answer» C. Demodulator | |
| 6635. |
In a ratio detector |
| A. | the linearity is worse than in a phase discriminator |
| B. | the output is twice that obtainable from a similar phase discriminator |
| C. | stabilization against signal strength variations is provided |
| D. | the circuit is the same as in a discriminator, except that the diodes are reversed |
| Answer» B. the output is twice that obtainable from a similar phase discriminator | |
| 6636. |
In a broadcast superheterodynes receiver having no RF amplifier, the loaded Q of the antenna coupling circuit is 100. If the intermediate frequency is 455 kHz. The image frequency at 25 MHz will be |
| A. | 24.09 MHz |
| B. | 24.54 MHz |
| C. | 25.45 MHz |
| D. | 25.91 MHz |
| Answer» E. | |
| 6637. |
Forward rating of an SCR is |
| A. | the maximum rate of rise of anode voltage which will trigger the SCR |
| B. | the maximum rate of rise of anode voltage which will not trigger the SCR if gate signal is applied |
| C. | the maximum rate of rise of anode voltage which will not trigger the SCR if gate signal is not applied |
| D. | either (b) or (c) |
| Answer» D. either (b) or (c) | |
| 6638. |
A crowbar circuit is generally needed for protection under fault conditions. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 6639. |
In a bridge inverter |
| A. | an output transformer is essential |
| B. | an output transformer is not essential |
| C. | an output transformer cannot be connected |
| D. | an output transformer, if used, can improve the efficiency of the circuit |
| Answer» C. an output transformer cannot be connected | |
| 6640. |
Modified Mc Murray full bridge inverter uses |
| A. | 4 thyristors and 2 diodes |
| B. | 4 thyristors and 4 diodes |
| C. | 8 thyristors and 4 diodes |
| D. | 8 thyristors and 8 diodes |
| Answer» E. | |
| 6641. |
McMurrary full bridge inverter uses |
| A. | auxiliary commutation |
| B. | complementary commutation |
| C. | natural commutation |
| D. | any of the above |
| Answer» B. complementary commutation | |
| 6642. |
The number of thyristors in a single phase fully controlled bridge rectifier is |
| A. | 16 |
| B. | 8 |
| C. | 4 |
| D. | 2 |
| Answer» D. 2 | |
| 6643. |
An ideal rectifier should have |
| A. | 100% efficiency, zero ripple factor, zero harmonic factor and unity displacement factor |
| B. | 100% efficiency, zero tipple factor, zero harmonic factor and zero displacement factor |
| C. | 100% efficiency, zero ripple factor, unity harmonic factor and unity displacement factor |
| D. | 100% efficiency, unity ripple factor, zero harmonic factor and unity displacement factor |
| Answer» B. 100% efficiency, zero tipple factor, zero harmonic factor and zero displacement factor | |
| 6644. |
When thyristors are connected in parallel, the current distribution may become non-uniform due to |
| A. | inductive effect of current carrying conductors |
| B. | capacitive effect of current carrying conductors |
| C. | both inductive and capacitive effects |
| D. | none of the above |
| Answer» B. capacitive effect of current carrying conductors | |
| 6645. |
The method of triggering SCS is |
| A. | application of positive pulse at cathode gate or negative pulse at anode gate |
| B. | application of pulse at anode gate |
| C. | application of pulse at cathode gate |
| D. | application of low voltage at anode |
| Answer» B. application of pulse at anode gate | |
| 6646. |
The application of gate signal decreases the break over voltage of on SCR. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 6647. |
The number of leads in a DIAC are |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 6 |
| Answer» B. 3 | |
| 6648. |
The condition for underdamped oscillations in a series RLC circuit is |
| A. | <img src="/_files/images/electronics-and-communication-engineering/power-electronics/267-35-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/power-electronics/267-35-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/power-electronics/267-35-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/power-electronics/267-35-4.png"> |
| Answer» C. <img src="/_files/images/electronics-and-communication-engineering/power-electronics/267-35-3.png"> | |
| 6649. |
Assertion (A): Gate triggering is the most commonly used method for triggering of an SCR.Reason (R): Even a small gate current is sufficient to turn on an SCR. |
| A. | Both A and R are correct and R is correct explanation of A |
| B. | Both A and R correct but R is not correct explanation of A |
| C. | A is correct but R is wrong |
| D. | A is wrong but R is correct |
| Answer» B. Both A and R correct but R is not correct explanation of A | |
| 6650. |
A static excitation system uses |
| A. | transformer and thyristors |
| B. | transformer and ac exciter |
| C. | dc exciter and ac exciter |
| D. | transformer and dc exciter |
| Answer» B. transformer and ac exciter | |