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.
| 851. |
An RLC series circuit is excited by a step voltage E. The circuit current at t = 0 is |
| A. | zero |
| B. | infinity |
| C. | s |
| Answer» D. | |
| 852. |
If J, I and a denote current density, current and area of cross section of a conductor, then |
| A. | J = Ia |
| B. | J = I/a2 |
| C. | J = I/a |
| D. | J = Ia2 |
| Answer» D. J = Ia2 | |
| 853. |
The circuit in figure(1) is replaced by that in figure(2). It remains same R0 will be |
| A. | zero |
| B. | R |
| C. | 2R |
| D. | 4R |
| Answer» E. | |
| 854. |
The resonant frequency of the circuit shown in figure is |
| A. | |
| B. | 4p Hz |
| C. | 2 p Hz |
| Answer» B. 4p Hz | |
| 855. |
To determine the polarity of voltage drop across a resistor, it is sufficient to know |
| A. | direction of current through the resistor |
| B. | direction and magnitude of current through the resistor |
| C. | direction and magnitude of current and value of resistance |
| D. | magnitude of current through the resistance |
| Answer» B. direction and magnitude of current through the resistor | |
| 856. |
The transfer function of a system is given by H(s) = 1/s2 (s - 2). The impulse response of the system is |
| A. | (te-2t) U(t) |
| B. | (te2t) U(t) |
| C. | 1 |
| D. | |
| Answer» C. 1 | |
| 857. |
Assertion (A): In an R-L circuit having high inductance, the rise of current is very slow.Reason (R): The time constant of R-L circuit is L/R. |
| 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 | |
| 858. |
Assertion (A): Thevenin's theorem and Norton's theorem are dual of each other.Reason (R): Voltage source can be converted into current source and vice versa. |
| A. | A is true but R is false |
| B. | A is false but R is true |
| C. | is 9 A and directed towards node 0 |
| D. | is 9 A and directed away from node 0 |
| Answer» B. A is false but R is true | |
| 859. |
Assertion (A): Millman's theorem helps in replacing a number of current sources in parallel by a single current source.Reason (R): Maximum power transfer theorem is applicable only for dc, circuits. |
| 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» D. A is false but R is true | |
| 860. |
When a lead acid cell is in fully charged condition the positive and negative plates are similar. |
| A. | 1 |
| B. | |
| C. | 30 μC each |
| D. | 60 μC each |
| Answer» C. 30 ŒºC each | |
| 861. |
In figure the number of tree branches and links respectively are |
| A. | 3 and 2 |
| B. | 1 and 3 |
| C. | 4 and 1 |
| D. | 1 and 4 |
| Answer» B. 1 and 3 | |
| 862. |
Two current sources each of rms value 10 A have frequencies 40 Hz and 50 Hz respectively. They are connected in series, the expression for resultant wave is |
| A. | i = 10 sin 40 t + 10 sin 50 t |
| B. | i = 14.14 sin 40 t + 14.14 sin 50 t |
| C. | i = 14.14 sin 80 pt + 14.14 sin 100 pt |
| D. | i = 20 sin 80 pt + 20 sin 100 pt |
| Answer» D. i = 20 sin 80 pt + 20 sin 100 pt | |
| 863. |
Assertion (A): The polynomial s3 + 6s2 + 12s + 8 is Hurwitz.Reason (R): In a Hurwitz polynomial all coefficients are non-negative. |
| 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 | |
| 864. |
For the star network of figure, the equivalent delta network is |
| A. | 1 |
| B. | |
| Answer» B. | |
| 865. |
In ZRC (s) = 0 at s = ‚àû, the last element in first Cauer form is |
| A. | R and C in series |
| B. | R and C in parallel |
| C. | H (s) has no poles or zeros in right half plane |
| D. | The poles of H(s) on the imaginary axis are simple with real and positive residues |
| Answer» C. H (s) has no poles or zeros in right half plane | |
| 866. |
A capacitor with initial charge q0 at t = 0+ acts as |
| A. | current source |
| B. | voltage source |
| C. | short-circuit |
| D. | open-circuit |
| Answer» D. open-circuit | |
| 867. |
The filter in figure, uses ideal op-amp. It is |
| A. | low pass filter |
| B. | high pass filter |
| C. | band pass filter |
| D. | band stop filter |
| Answer» B. high pass filter | |
| 868. |
In figure, the transmission parameters are A = C = 1, B = 2 and D = 3. Then Zin = |
| A. | 12/13 Ω |
| B. | 13/12 Ω |
| C. | 3 Ω |
| D. | 4 Ω |
| Answer» B. 13/12 Œ© | |
| 869. |
The current wave shown in figure is applied by a 0.1 F capacitor at t = 0. At t = 0+, the voltage across capacitor is |
| A. | 10 V |
| B. | 20 V |
| Answer» B. 20 V | |
| 870. |
The dual of a link is |
| A. | twig |
| B. | node |
| C. | loop |
| D. | tree branch |
| Answer» E. | |
| 871. |
The sum of positive real functions |
| A. | is a positive real function |
| B. | may be a positive real function or not |
| C. | can not be a positive real function |
| D. | either (b) or (c) |
| Answer» D. either (b) or (c) | |
| 872. |
A system function the resonant frequency in rad/sec and bandwidth in rad/sec is given by |
| A. | 5, 10 |
| B. | 5, 4 |
| C. | 10, 4 |
| D. | 10, 10 |
| Answer» D. 10, 10 | |
| 873. |
For graph of figure, one set of fundamental cutsets would be |
| A. | cbfe, afe, bdf |
| B. | cbd, adbe, cde |
| C. | lamp L1 only |
| D. | lamps L1 and L2 |
| Answer» B. cbd, adbe, cde | |
| 874. |
Wave A starts its positive half cycle at ωt = 30° and wave B starts its positive half cycle at ωt = 75° then wave B is leading wave A by 45°. |
| A. | 1 |
| B. | |
| 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 | |
| 875. |
If a 'live' conductor of a public supply touches earth metal |
| A. | supply voltage will increase |
| B. | supply voltage will decrease |
| C. | no current will flow |
| D. | current will flow to earth |
| Answer» E. | |
| 876. |
The circuit shown in figure, will act as an ideal current source with respect to terminals A and B, when frequency is |
| A. | 4 rad/s |
| B. | 16 rad/s |
| C. | an inductance of value K0 in series |
| D. | an inductance of value 1/K0 in series |
| Answer» D. an inductance of value 1/K0 in series | |
| 877. |
In a series circuit with fixed R and variable XL, the current locus lies in the fourth quadrant. |
| A. | 1 |
| B. | |
| C. | RC circuit |
| D. | RL |
| Answer» B. | |
| 878. |
A circuit is replaced by its Thevenin's equivalent to find current through a certain branch. If VTH = 10 V and RTH = 20 Ω, the current through the branch |
| A. | will always be 0.5 A |
| B. | will always be less than 0.5 A |
| C. | will always be equal to or less than 0.5 A |
| D. | may be 0.5 A or more or less |
| Answer» D. may be 0.5 A or more or less | |
| 879. |
Assertion (A): A series RLC circuit resonates when excited by variable frequency source.Reason (R): Resonant frequency is geometric mean of half power frequencies. |
| 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 | |
| 880. |
A series resonant circuit has R = 2 Ω, L = 0.1 H and C =10 μF. At resonance applied voltage = 10 ∠0 V. Voltage across inductance is likely to be |
| A. | 10 ∠0 V |
| B. | 10 ∠45° V |
| C. | 100 ∠90° V |
| D. | 100 ∠-90° V |
| Answer» D. 100 ‚à†-90¬∞ V | |
| 881. |
In the circuit shown in figure, Is = 4A, Vs = 4, the voltage V is given by |
| A. | 6 V |
| B. | 8 V |
| C. | 4 V |
| D. | 2 V |
| Answer» B. 8 V | |
| 882. |
If a resistance R of 1 Ω is connected between A and B in figure, current flowing through R is |
| A. | 0.041666666666667 |
| B. | 0.5 A |
| C. | 0.25 A |
| D. | 0.125 A |
| Answer» D. 0.125 A | |
| 883. |
A thermal power plant has an efficiency of 0.4. If 0.6 kg of coal is burnt to generate 1 kWh, the calorific value of coal is |
| A. | about 3500 kcal/kg |
| B. | about 2500 kcal/kg |
| C. | about 1500 kcal/kg |
| D. | about 7500 kcal/kg |
| Answer» B. about 2500 kcal/kg | |
| 884. |
In an R-L circuit, the impedance is 30 Ω at a frequency of 100 Hz. At 200 Hz, the impedance should be |
| A. | 30 Ω or more |
| B. | 60 Ω or more |
| C. | 15 Ω or less |
| D. | more than 30 Ω but less than 60 Ω |
| Answer» E. | |
| 885. |
In all insulators the bonding is covalent. |
| A. | 1 |
| B. | |
| C. | AC/BD |
| D. | BD/AC |
| Answer» C. AC/BD | |
| 886. |
If then the value of is |
| A. | not determined |
| B. | zero |
| C. | 1 |
| D. | ‚àû |
| Answer» B. zero | |
| 887. |
In the Bode plot, of , the phase at w = 15 is |
| A. | ‚àû |
| B. | 45 |
| C. | 40 |
| D. | 36.8 |
| Answer» E. | |
| 888. |
A constant k band stop filter has cutoff frequencies of 1000 and 4000 Hz. The attenuation will be maximum when frequency is |
| A. | 2000 Hz |
| B. | 1000 Hz |
| C. | Compensation theorem |
| D. | Bisectional theorem |
| Answer» D. Bisectional theorem | |
| 889. |
Assertion (A): Two terminal black boxes of R and C can be identified by plotting their static V-I characteristics.Reason (R): The V-I characteristic of resistance is a straight line of slope R passing through origin. |
| 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» E. | |
| 890. |
In ac circuits maximum power is delivered to a load if load impedance is conjugate of source impedance. |
| A. | 1 |
| B. | |
| C. | current is maximum |
| D. | current is minimum |
| Answer» B. | |
| 891. |
A variable resistance R and capacitive reactance XC are fed by an voltage. The current locus is |
| A. | a semi circle in 4th quadrant |
| B. | a semi circle in first quadrant |
| C. | a straight line in 4th quadrant |
| D. | a straight line first quadrant |
| Answer» C. a straight line in 4th quadrant | |
| 892. |
In the circuit shown in the figure, steady-state was reached when the switch S was open. The switch was closed at t = 0. The initial value of the current through the capacitor 2 C is |
| A. | zero |
| B. | 0.041666666666667 |
| C. | 0.083333333333333 |
| D. | 0.125 |
| Answer» D. 0.125 | |
| 893. |
In figure, the current after a long time after closing of switch is |
| A. | 0.041666666666667 |
| B. | 0.083333333333333 |
| C. | 0 |
| D. | infinity |
| Answer» C. 0 | |
| 894. |
For stable network, the real part of poles and zeros of driving point function must be |
| A. | zero |
| B. | positive |
| C. | Ri > RL |
| D. | Ri < RL |
| Answer» C. Ri > RL | |
| 895. |
In figure readings of the two voltmeters should be |
| A. | 100 V on each meter |
| B. | 200 V on each meter |
| C. | 150 V on V1 and 50 V on V2 |
| D. | 50 V on V1 and 150 V on V2 |
| Answer» C. 150 V on V1 and 50 V on V2 | |
| 896. |
In the network of figure it is desired that maximum power be supplied to Z2. The values of Z1 and Z2 are fixed. However the transformation ratio 'a' of transformer can be changed. The value of 'a' for maximum power transfer is |
| A. | |Z2|/|Z1| |
| B. | [|Z2|/|Z1|]0.5 |
| C. | [|Z2|/|Z1|]2 |
| D. | [|Z2|/|Z1|]0.75 |
| Answer» C. [|Z2|/|Z1|]2 | |
| 897. |
An RC series circuit is charged by a voltage E. After a long time the battery is removed and a short circuit is placed across R-C. Then |
| A. | the polarity of voltage across R is same during discharge and during charge |
| B. | the polarity of voltage across R during discharging is opposite to that during charging |
| C. | the polarity of voltage across R depends on time constant RC |
| D. | none of the above |
| Answer» C. the polarity of voltage across R depends on time constant RC | |
| 898. |
For an RC impedance function |
| A. | all poles lie on jω axis |
| B. | all poles are simple , |
| C. | all poles are simple and lie on negative real axis |
| D. | none of the above |
| Answer» D. none of the above | |
| 899. |
In attenuation band, β is an odd multiple of p. |
| A. | 1 |
| B. | |
| C. | 1, 2 and 3 |
| D. | 2, 3 and 4 |
| Answer» B. | |
| 900. |
Assertion (A): A graph can have many trees.Reason (R): The number of tree branches is equal to number of nodes. |
| A. | A is true but R is false |
| B. | A is false but R is true |
| C. | always fatal |
| D. | never fatal |
| Answer» E. | |