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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.
| 701. |
For a two port network to be reciprocal |
| A. | Z11 = Z22 |
| B. | y12 = y21 |
| C. | h21 = - h12 |
| D. | AD - BC = 0 |
| Answer» D. AD - BC = 0 | |
| 702. |
A specimen of a material has a resistivity of 1.78 x 108 ohm-m. The material is |
| A. | semiconductor |
| B. | conductor |
| C. | semiconductor or conductor |
| D. | insulator |
| Answer» E. | |
| 703. |
At a frequency less than the resonant frequency |
| A. | series circuit is inductive and parallel circuit is capacitive |
| B. | series circuit is capacitive and parallel circuit is inductive |
| C. | both circuits are capacitive |
| D. | both circuits are inductive |
| Answer» C. both circuits are capacitive | |
| 704. |
In the synthesis of RLC network |
| A. | the number of elements in Bott-Duffin synthesis and Brune's synthesis are always equal |
| B. | the number of elements in Bott-Duffin synthesis is more than that in Brune's synthesis |
| C. | the number of elements in Bott-Duffin synthesis is less than that in Brune's synthesis |
| D. | the number of elements in Bott-Duffin synthesis may be more or less than that in Brune's synthesis |
| Answer» C. the number of elements in Bott-Duffin synthesis is less than that in Brune's synthesis | |
| 705. |
Two similar coupled coils are connected in series. The total inductance in series aiding connection is 100 mH. If currents is 3 A, the energy stored in magnetic field is |
| A. | 0.9 J |
| B. | 0.45 J |
| C. | 0.225 J |
| D. | 1.8 J |
| Answer» D. 1.8 J | |
| 706. |
The circuit in figure has reached steady values with switch open. If switch is closed at t = 0 the voltage across 2 μF capacitance at t = 0+ is |
| A. | zero |
| B. | 4 V |
| C. | 6 V |
| D. | 10 V |
| Answer» B. 4 V | |
| 707. |
In the circuit of figure, the switch is closed at t = 0. At t = 0+ the current supplied by battery is |
| A. | 0 |
| B. | 0.20833333333333 |
| C. | less than 5A |
| D. | infinity |
| Answer» B. 0.20833333333333 | |
| 708. |
The Laplace transform of a continuous-time signal x(t) is If the Fourier transform of this signal exists, then x(t) is |
| A. | e2tu(t) - 2e-tu(t) |
| B. | - e2tu(- t) - 2e-tu(t) |
| C. | - e2tu(- t) + 2e-tu(t) |
| D. | e2tu(- t) - 2e-tu(t) |
| Answer» E. | |
| 709. |
The total lumens emitted by a source of 1 candle are |
| A. | 0.58333333333333 |
| B. | 0.83333333333333 |
| C. | time for which current is passed |
| D. | magnitude of current |
| Answer» C. time for which current is passed | |
| 710. |
The dual of quantity charge is |
| A. | current |
| B. | Voltage |
| C. | flux |
| D. | dΦ/dt |
| Answer» D. dŒ¶/dt | |
| 711. |
In a resistor the current is i and the voltage is v. The rate of dissipation of heat at any time t is |
| A. | vi |
| B. | vit |
| C. | vt |
| D. | vit2 |
| Answer» B. vit | |
| 712. |
If an admittance Y(s) has a term Ks, the realization would give |
| A. | an inductance of value K |
| B. | a resistance of value K |
| C. | a capacitance of value K |
| D. | either (a) or(c) |
| Answer» B. a resistance of value K | |
| 713. |
Carbon resistances are used in very high values. |
| A. | 1 |
| B. | |
| C. | z11 = z22 |
| D. | z12 z22 = z11 z22 |
| Answer» B. | |
| 714. |
The function δ (t - b) is a |
| A. | unit impulse |
| B. | unit step |
| C. | unit doublet |
| D. | none of the above |
| Answer» D. none of the above | |
| 715. |
A practical Parallel resonant circuit has a coil in Parallel with a 0.14 μf capacitor. The coil has an inductance of 1 mH and a resistance of 10 ohms. The Q of the circuit is |
| A. | 1000 |
| B. | 100 |
| C. | 10 |
| D. | 1 |
| Answer» D. 1 | |
| 716. |
In figure, iL at t = 0+ is |
| A. | 0 |
| B. | I |
| C. | infinite |
| Answer» B. I | |
| 717. |
The Thevenin equivalent circuit to the left of AB has Req |
| A. | 2 Ω |
| B. | 4 Ω |
| C. | 1 Ω |
| D. | 3 Ω |
| Answer» D. 3 Œ© | |
| 718. |
Network transients are due to |
| A. | circuit resistance |
| B. | circuit voltage |
| C. | changes in energy stored in L and C |
| D. | circuit admittance |
| Answer» D. circuit admittance | |
| 719. |
Assertion (A): Power is the rate at which energy is supplied.Reason (R): Energy = VIt. |
| 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» B. Both A and R are true and R is not the correct explanation of A | |
| 720. |
A capacitor can be represented by a capacitance C in parallel with a resistance R. For a good capacitor, the resistance R should be |
| A. | very high |
| B. | high |
| C. | very low |
| D. | low |
| Answer» B. high | |
| 721. |
A Two port network has V1 = 24 I1 + 8 I2 and V2 = 8 I1 + 32 I2 which of the following networks is represented by above equation? |
| A. | |
| B. | |
| Answer» C. | |
| 722. |
Two similar mutually coupled coils have a total inductance of 900 mH and coefficient of coupling 0.5. The self inductance of each coils is |
| A. | 300 mH |
| B. | 150 mH |
| C. | 75 mH |
| D. | 50 mH |
| Answer» B. 150 mH | |
| 723. |
If a capacitor is charged by a square wave current source the voltage across the capacitor is |
| A. | triangular wave |
| B. | step function |
| C. | zero |
| D. | square wave |
| Answer» B. step function | |
| 724. |
In figure, the capacitor is charged to 1 V. At t = 0 the switch is closed so that i = e-t. When i = 0.37 A, the voltage across capacitor is |
| A. | 1 V |
| B. | 0.63 V |
| C. | 0.37 V |
| D. | 0.185 V |
| Answer» D. 0.185 V | |
| 725. |
The transfer function V2/V1 for figure has |
| A. | a zero at origin |
| B. | a zero at infinity |
| C. | no zero |
| D. | a zero at j1 |
| Answer» E. | |
| 726. |
Two coupled coils lie in parallel planes such that 50% of magnetic flux produced by one links the other. The coefficient of coupling is |
| A. | 0.5 |
| B. | 0.25 |
| C. | 0.125 |
| D. | 0.5 |
| Answer» B. 0.25 | |
| 727. |
The function is |
| A. | RC function |
| B. | LC function |
| C. | RL function |
| D. | RC or RL function |
| Answer» C. RL function | |
| 728. |
In open circuit impedance parameters, the independent variables are |
| A. | I1 and I2 |
| B. | V1 and V2 |
| C. | V1 and I1 |
| D. | V2 and I2 |
| Answer» B. V1 and V2 | |
| 729. |
When a lead acid battery is being charged, the specific gravity of the electrolyte |
| A. | decreases |
| B. | increases |
| C. | either increases or decreases |
| D. | remains the same |
| Answer» C. either increases or decreases | |
| 730. |
The units for apparent power are watts. |
| A. | 1 |
| B. | |
| C. | resistive circuit |
| D. | RC circuit |
| Answer» C. resistive circuit | |
| 731. |
Two coupled coils have self inductance L1 and L2. The coefficients of coupling is k. The mutual inductance is |
| A. | kL1L2 |
| B. | kL1L2 |
| C. | steady state |
| D. | transient state |
| Answer» D. transient state | |
| 732. |
The time constant of the network shown in figure is, when switch is closed. |
| A. | 2RC |
| B. | |
| C. | RC/2 |
| Answer» B. | |
| 733. |
When a 10 K, 10%, 1/4 Ω resistor is connected in series with a 12 K, ± 1%, 1/4 Ω resistor, the resulting combination has the following specifications |
| A. | 22 K, ± 11%, 1/2 Ω |
| B. | 22 K, ± 5.5%, 1/2 Ω |
| C. | 22 K, ± 5.5%, 1/8 Ω |
| D. | none of these |
| Answer» C. 22 K, ¬± 5.5%, 1/8 Œ© | |
| 734. |
A resistance and an inductance are connected in parallel and fed from 50 Hz ac mains. Each branch takes a current of 5 A. The current supplied by source is |
| A. | 0.20833333333333 |
| B. | zero |
| C. | Both A and R are true and R is correct explanation of A |
| D. | Both A and R are true and R is not the correct explanation of A |
| Answer» C. Both A and R are true and R is correct explanation of A | |
| 735. |
A capacitor behave to d.c. as |
| A. | short-circuit |
| B. | an open-circuit |
| C. | it behaves to a.c. |
| D. | none of these. |
| Answer» C. it behaves to a.c. | |
| 736. |
A series RC circuit has fixed XC, and variable R. The current locus is in the first quadrant. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 737. |
If operator 'a' = 1 ∠120° then (1 + a + a2) = |
| A. | #NAME? |
| B. | #VALUE! |
| C. | 1 |
| D. | 0 |
| Answer» E. | |
| 738. |
A function Z(s) has zero at infinity if |
| A. | the degree of numerator and denominator are equal |
| B. | the numerator of Z(s) is one degree higher than denominator |
| C. | the denominator of Z(s) is one degree higher than numerator |
| D. | the degree of numerator and denominator are either equal or differ by one |
| Answer» D. the degree of numerator and denominator are either equal or differ by one | |
| 739. |
In figure, capacitor is used to develop pulses of short duration and large duty cycle across R2 when switch is closed. Which of the following combinations is best suited? |
| A. | R1 and R2 large but C small |
| B. | R1 and R2 small but C large |
| C. | R1 and C large and R2 small |
| D. | R2 and C large but R1 small |
| Answer» D. R2 and C large but R1 small | |
| 740. |
The value of current read by ideal ammeter A in figure is __________ ampere. |
| A. | 0 |
| B. | 3 |
| C. | 2.5 |
| D. | 5 |
| Answer» E. | |
| 741. |
In figure, the current through R is 1 A when VA = 0 and VB = 15V. If both VA and VB are increased by 15V each, current through R will be |
| A. | 0.125 |
| B. | 0.33 A |
| C. | 1 |
| D. | |
| Answer» D. | |
| 742. |
A certain network has two ideal voltages sources and a large number of ideal resistances. The power consumed in one of the resistances is 4 W when either of two sources is active and the other source is active and the other source is short circuited. When both sources is short circuited.When both sources are active, the power consumed in the same resistor would be |
| A. | zero or 16 W |
| B. | 4 W or 8 W |
| C. | zero or 8 W |
| D. | 8 W or 16 W |
| Answer» B. 4 W or 8 W | |
| 743. |
In a sine wave, maximum rate of change of voltage occurs at |
| A. | ascent of the waveform |
| B. | #NAME? |
| C. | #NAME? |
| D. | between maximum and minimum |
| Answer» E. | |
| 744. |
For the network in figure, the correct loop equation for loop 3 is |
| A. | -I1 + 4I2 + 11I3 = 0 |
| B. | I1 + 4I2 + 11I3 = 0 |
| C. | -I1 - 4I2 + 11I3 = 0 |
| D. | I1 - 4I2 + 6I3 = 0 |
| Answer» D. I1 - 4I2 + 6I3 = 0 | |
| 745. |
A delta connection contains three impedances of 60 Ω each. The impedances of equivalent star connection will be |
| A. | 15 Ω |
| B. | 20 Ω |
| C. | 30 Ω |
| D. | 40 Ω |
| Answer» C. 30 Œ© | |
| 746. |
A system defined by is initially at rest, and x = u(t) sin 2t then the forced response is K sin (2t - θ). The value of θ given by |
| A. | -tan-1(1) |
| B. | -tan-1(2) |
| C. | |
| Answer» C. | |
| 747. |
As the number SWG increases, area of cross-section decreases. |
| A. | 1 |
| B. | |
| C. | R |
| D. | C |
| Answer» B. | |
| 748. |
In a varistor the v-i graph is linear. |
| A. | 1 |
| B. | |
| C. | 0.16666666666667 |
| D. | 2.5 A |
| Answer» C. 0.16666666666667 | |
| 749. |
A sawtooth current wave is passed through a resistance |
| A. | the waveshapes of voltages across resistance and power will also the sawtooth |
| B. | the waveshape of voltage across resistance will be sawtooth |
| C. | the waveshape of power will be sawtooth |
| D. | neither the voltage waveshape nor power wave-shape will be sawtooth |
| Answer» C. the waveshape of power will be sawtooth | |
| 750. |
An ideal current source has |
| A. | infinite source resistance |
| B. | zero source resistance |
| C. | large value of source resistance |
| D. | finite value of source resistance |
| Answer» B. zero source resistance | |