MCQOPTIONS
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MCQOPTIONS
This section includes 1800 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.
| 651. |
The Laplace transform of i(t) is given by As t ‚Üí ‚àû the value of i(t), tends to |
| A. | 0 |
| B. | 2 |
| C. | 1 |
| D. | ‚àû |
| Answer» C. 1 | |
| 652. |
The Thevenin's equivalent of network in figure(1) is a 10 V source in series with 2 Ω resistance. If a 3 Ω resistance is connected across AB as shown in figure(2) the Thevenin's equivalent is |
| A. | 10 V in series with 5 Ω resistance |
| B. | 6 V in series with 5 Ω resistance |
| Answer» C. | |
| 653. |
The response of a function is decided by |
| A. | the location of its zeros |
| B. | the location of its poles |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» D. none of the above | |
| 654. |
The correct relation between energy and charge is |
| A. | Energy = voltage/charge |
| B. | Charge = Energy x voltage |
| C. | Energy = voltage (charge)0.5 |
| D. | Energy = voltage x charge |
| Answer» E. | |
| 655. |
For addition and subtraction operations, phasors |
| A. | must be represented in polar form |
| B. | must be represented in rectangular form |
| C. | may be represented in any form |
| D. | none of the above |
| Answer» C. may be represented in any form | |
| 656. |
Lead becomes a superconductor at |
| A. | 9.1 K |
| B. | 7 K |
| C. | 5 K |
| D. | 3 K |
| Answer» C. 5 K | |
| 657. |
For a series circuit of variable R and XL, the impedance locus is |
| A. | a straight line parallel to Y axis in second quadrant |
| B. | a straight line parallel to Y axis in first quadrant |
| Answer» B. a straight line parallel to Y axis in first quadrant | |
| 658. |
In gases the flow of current is due to |
| A. | positive ions only |
| B. | electrons only |
| C. | electrons, positive ions and negative ions |
| D. | electrons and positive ions |
| Answer» D. electrons and positive ions | |
| 659. |
The parameter A of a two port network is equal to |
| A. | V2/V1 with I1 = 0 |
| B. | V1/I2 with V2 = 0 |
| C. | I1/I2 with V2 = 0 |
| D. | V1/V2 with I2 = 0 |
| Answer» E. | |
| 660. |
In ZRC (s) = constant at s = 0, the last element in first Foster cauer realization is |
| A. | R |
| B. | C |
| C. | R and C in series |
| D. | R and C in parallel |
| Answer» B. C | |
| 661. |
A coil of resistance R and inductance L is connected in series with 5 μF capacitor. The source frequency is equal to resonance frequency and circuit current is 0.5 A. Another 5 F capacitor is connected in parallel with the above capacitor. The circuit current will be |
| A. | 0.5 A |
| B. | more than 0.5 A |
| C. | less than 0.5 A |
| D. | 0.5 A or less |
| Answer» D. 0.5 A or less | |
| 662. |
Force = Electric intensity x current. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 663. |
Which of the following theorems can be conveniently used to find power consumed in 10 Ω resistor in figure? |
| A. | Thevenin theorem |
| B. | Maximum power transfer theorem |
| C. | Millman's theorem |
| D. | Superposition theorem |
| Answer» E. | |
| 664. |
If A = 3 + j1, A4 |
| A. | 100 ∠18.43° |
| B. | 100 ∠73.72° |
| C. | 10 ∠18.43° |
| D. | 10 ∠73.72° |
| Answer» C. 10 ‚à†18.43¬∞ | |
| 665. |
Bus bars are always meant for very heavy currents. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 666. |
The low pass filter characteristic shown in figure realizable. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 667. |
The circuit shown in the figure, with R = 1/3 Ω, L = 1/4H, C = 3F has input voltage v(t) = sin2t. The resulting current i(t) is |
| A. | 5 sin (2t + 53.1°) |
| B. | 5 sin (2t - 53.1°) |
| C. | 25 sin (2t + 53.1°) |
| D. | 25 sin (2t - 53.1°) |
| Answer» B. 5 sin (2t - 53.1¬∞) | |
| 668. |
A conductor has a cylindrical shape with a diameter d. Its resistance is 2 Ω. It is recast into a cylindrical conductor of diameter 0.3d. The resistance of new conductor is likely to be |
| A. | less than 2 Ω |
| B. | less than 0.6 Ω |
| C. | between 2 and 100 Ω |
| D. | more than 100 Ω |
| Answer» E. | |
| 669. |
In figure, the battery has remained switched on for a long time. At t = 0 the switch is closed. The current i(t) is likely to be |
| A. | 6 + 3e-1 |
| B. | 3 - 6e-1 |
| Answer» C. | |
| 670. |
A steel bar needs 1200 AT to magnetise it. The voltage that must be applied to the magnetising coil of 100 turns and 10 Ω resistance is __________ volt. |
| A. | 1200 |
| B. | 10 |
| Answer» B. 10 | |
| 671. |
While calculating Norton's resistance, all current sources are short circuited. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 672. |
Poles and zeros of a driving point function of a network are simple and alternate on jω axis. The network consists of |
| A. | R and L |
| B. | R, L and C |
| Answer» C. | |
| 673. |
In figure, the current supplied by battery at t = 0.5s is |
| A. | 1.1 A |
| B. | 1.9 A |
| C. | 0 |
| D. | 1.632 A |
| Answer» E. | |
| 674. |
A resistor R of 1 Ω and two inductor L1 and L2 of inductances 1 H and 2 H respectively, are connected in parallel. At some time, the current through L1 and L2 are 1 A and 2 A, respectively. The current through R at time t = ∞ will be |
| A. | zero |
| B. | 0.041666666666667 |
| C. | 0.083333333333333 |
| D. | 0.125 |
| Answer» B. 0.041666666666667 | |
| 675. |
Choose the correct option, if b (branch), n (nodes), l (links) |
| A. | b = n + l - 1 |
| B. | no. of twig = n - 1 |
| C. | b = n - l + 1 |
| D. | b, a |
| Answer» E. | |
| 676. |
Open-circuit voltage is the potential difference between two point when the impedance between these points is |
| A. | zero |
| B. | infinity |
| C. | capacitive |
| D. | reactive |
| Answer» C. capacitive | |
| 677. |
If A = 10 + j then logeA is |
| A. | 14.14 ∠45° |
| B. | 200 ∠45° |
| C. | 2.65 + j45° |
| D. | 2.65 + j0.785 |
| Answer» E. | |
| 678. |
Assertion (A): In state space analysis, capacitors are taken to be in tree.Reason (R): State variable analysis is very suitable for computer solution. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true and R is not the correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» C. A is true but R is false | |
| 679. |
Find RL for maximum power transfer |
| A. | 3 Ω |
| B. | 1.125 Ω |
| C. | 4.17 Ω |
| D. | none |
| Answer» B. 1.125 Œ© | |
| 680. |
Out of Metal-film type and Carbon-film type, the one with better tolerance specification is |
| A. | both have same tolerance |
| B. | none of these |
| Answer» C. | |
| 681. |
In the circuit of figure the switch is open for a long time, At t = 0 the switch is closed. At t = 0+ the current supplied by battery is |
| A. | 3.6 A |
| B. | 1.5 A |
| Answer» C. | |
| 682. |
For the given circuit, the current I is |
| A. | 0.083333333333333 |
| B. | 0.20833333333333 |
| C. | 0.29166666666667 |
| D. | 0.33333333333333 |
| Answer» D. 0.33333333333333 | |
| 683. |
A network has only independent current sources and resistance. If values of all resistors are doubled, the values of node voltages |
| A. | will become half |
| B. | will remain unchanged |
| C. | will become double |
| D. | cannot be determined unless circuit configuration and values of resistors are known |
| Answer» D. cannot be determined unless circuit configuration and values of resistors are known | |
| 684. |
In series as well as parallel resonant circuits, increasing the value of resistance would lead to |
| A. | decrease in bandwidth of both the circuits |
| B. | increase in bandwidth of both the circuits |
| C. | decrease in bandwidth in series circuit and increase in parallel circuit |
| D. | increase in bandwidth in series circuit and decrease in parallel circuit |
| Answer» D. increase in bandwidth in series circuit and decrease in parallel circuit | |
| 685. |
In figure, the effective capacitance between A and B is |
| A. | 8 μF |
| B. | 10 μF |
| Answer» C. | |
| 686. |
Assertion (A): In figure the coefficients , n = 1, 2, ... and bn = 0Reason (R): The periodic function is symmetrical about t = T and t = T/2. |
| A. | A is true but R is false |
| B. | A is false but R is true |
| Answer» B. A is false but R is true | |
| 687. |
Kirchoff's voltage law is not valid for a non-linear network |
| A. | can't say |
| B. | none of the above |
| Answer» C. | |
| 688. |
Two coils having equal resistance but different inductances are connected in series. The time constant of the series combination is |
| A. | average of the time constants of individual coils |
| B. | sum of the time constants of the individual coils |
| C. | geometric mean of the time constants of individual coils |
| D. | product of the time constants of the individual coils |
| Answer» B. sum of the time constants of the individual coils | |
| 689. |
In figure, the current through 10 V battery is |
| A. | 0 |
| B. | 0.5 A charging |
| C. | 0.5 A discharging |
| D. | none of the above |
| Answer» B. 0.5 A charging | |
| 690. |
Quality factor will be |
| A. | b/a |
| B. | ab |
| Answer» B. ab | |
| 691. |
An inductance having XL = 5 Ω and a capacitance having XC = 5 Ω are connected in parallel across 100 V, 50 Hz supply. The current drawn from source is |
| A. | zero |
| B. | 20 A |
| C. | 40 A |
| D. | 28.28 A |
| Answer» B. 20 A | |
| 692. |
The electric energy required to raise the temperature of a given amount of water is 1000 kWh. If heat losses are 25%, the total heating energy required is __________ kWh. |
| A. | 1500 |
| B. | 1250 |
| C. | 1333 |
| D. | 1000 |
| Answer» C. 1333 | |
| 693. |
The average value of the waveform is |
| A. | 2 V |
| B. | 0 V |
| C. | 4 V |
| D. | 3 V |
| Answer» C. 4 V | |
| 694. |
In metals, the flow of current is due to |
| A. | electrons |
| B. | ions |
| C. | holes |
| D. | electrons and ions |
| Answer» B. ions | |
| 695. |
A wire has a resistance R ohm. If another wire of the same material and same weight has double the diameter (as compared to the first wire), the resistance of the second wire will be |
| A. | 0.5 R |
| B. | 0.25 R |
| C. | 0.125 R |
| D. | R/16 |
| Answer» E. | |
| 696. |
The current through a 10 Ω resistance in a dc circuit having two emf sources is 3A. If this resistance is changed to 20 Ω, the new value of current will be |
| A. | less than 3 A |
| B. | equal or less than 3 A |
| C. | equal to or less or more than 3 A |
| D. | 1.5 A |
| Answer» B. equal or less than 3 A | |
| 697. |
When a source is delivering maximum power to a load through a network, the ratio of power delivered to the source power |
| A. | may be 50% or more than 50% |
| B. | may be 50% or more less than 50% |
| Answer» B. may be 50% or more less than 50% | |
| 698. |
In an air cored coil, a current of 0.7 A causes a flux of 5 x 10-6 Wb. If the core is made of cast iron and the coil is similar, the same current can set up a flux of about |
| A. | 5 x 10-6 Wb |
| B. | 5 x 10-8 Wb |
| C. | 10-2 Wb |
| D. | 5 x 10-4 Wb |
| Answer» E. | |
| 699. |
In the circuit of figure the current through L at t = ‚àû is |
| A. | 0 |
| B. | 0.41666666666667 |
| C. | 6.67 A |
| D. | 5.1 A |
| Answer» C. 6.67 A | |
| 700. |
In the circuit shown in figure the current I of sinusoidal source is |
| A. | 25 A |
| B. | 0.16666666666667 |
| C. | 20 A |
| D. | Not determinable from given data |
| Answer» D. Not determinable from given data | |