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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.
| 751. |
The power dissipated in 4 Ω resistance in figure is |
| A. | 64 W |
| B. | 32 W |
| C. | 16 W |
| D. | 8 W |
| Answer» D. 8 W | |
| 752. |
Double integration of unit step function leads to |
| A. | an impulse |
| B. | a parabola |
| C. | a ramp |
| D. | a doublet |
| Answer» C. a ramp | |
| 753. |
For a transfer function the coefficients of the numerator and denominator polynomials in s must be real. |
| A. | 1 |
| B. | |
| C. | 120 |
| D. | 12 |
| Answer» B. | |
| 754. |
To find the current in a 20 Ω resistance connected in a circuit, Norton's theorem is used. IN = 7.5 A. The current though 20 Ω resistance. |
| A. | is 7.5 A |
| B. | is less than 7.5 A |
| C. | may be 7.5 A or less |
| D. | may be 7.5 A or more or less |
| Answer» C. may be 7.5 A or less | |
| 755. |
Heat in calories = I2Rt/4.186. |
| A. | 1 |
| B. | |
| C. | R and C |
| D. | L and C |
| Answer» B. | |
| 756. |
An ac circuit has two branches in parallel. The impedances of the two branches are equal. Their power factors are 0.8 lagging and 0.8 leading. The overall p.f. is |
| A. | Number of links = Number of branches - number of nodes + 1 |
| B. | Number of links = Number of branches - number of nodes |
| C. | Number of links = Number of branches - number of nodes - 1 |
| D. | Number of links = Number of branches - number of nodes - 2 |
| Answer» B. Number of links = Number of branches - number of nodes | |
| 757. |
In f(t) = δ(t - T), F(s) = |
| A. | all sources must be open circuited |
| B. | all sources must be short circuited |
| C. | all voltages sources must be open circuited and all current sources must be short circuited |
| D. | all sources must be replaced by their internal resistances |
| Answer» D. all sources must be replaced by their internal resistances | |
| 758. |
In the circuit of figure, the current through battery E2 is |
| A. | 1 A discharging |
| B. | 1 A charging |
| C. | 9 A discharging |
| D. | 9 A charging |
| Answer» C. 9 A discharging | |
| 759. |
The function H (s) is positive real if |
| A. | Re [H(jω)] ≥ 0 for 0 ≤ ω ≤ ∞ |
| B. | all of the above |
| C. | vapour-filled bulb |
| D. | high-expansion steel rod |
| Answer» E. | |
| 760. |
The pole zero diagram of an impedance Z has a pole at s = - 6 and zero at s = - 4 as shown in figure the constant multiplier k = 1. For a signal Is = cos 6t, the steady state voltage across Z is given in magnitude as under |
| A. | 0.6 |
| B. | 0.84 |
| C. | 7.2 |
| D. | none |
| Answer» C. 7.2 | |
| 761. |
Form factor for a sine wave is |
| A. | 1.414 |
| B. | 0.707 |
| C. | 1.11 |
| D. | 0.637 |
| Answer» D. 0.637 | |
| 762. |
If R, L, C are in parallel, the currents through L and C are equal in magnitude at resonance. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» B. | |
| 763. |
For a rectified sinusoidal wave clipped at 0.707 its peak value (figure), the average value is |
| A. | 70.7 V |
| B. | 63.7 V |
| C. | 54 V |
| D. | 15 V |
| Answer» D. 15 V | |
| 764. |
If H(s) is positive real, 1/H(s) |
| A. | is positive real |
| B. | is not positive real |
| C. | may or may not be positive real |
| D. | must possess some other properties also if it is to be positive real |
| Answer» E. | |
| 765. |
Twelve 1 Ω resistance are used as edges to form a cube. The resistance between two diagonally opposite corners of the cube is |
| A. | 5/6 Ω |
| B. | 1 Ω |
| C. | 6/5 Ω |
| D. | 3/2 Ω |
| Answer» B. 1 Œ© | |
| 766. |
The reading of the voltmeter in figure will be __________ volt. |
| A. | 100 |
| B. | 150 |
| C. | zero |
| D. | 200 |
| Answer» D. 200 | |
| 767. |
The closing of switch S1 and S2 in figure will light up |
| A. | none of them |
| B. | lamp L2 only |
| C. | carbon-film |
| D. | metal-film type |
| Answer» C. carbon-film | |
| 768. |
Assertion (A): For networks in figure (1) and (2) sum of products of branch voltages and branch currents at any time is zero.Reason (R): The networks in figure (1) and (2) are not the same structurally. |
| A. | A is true but R is false |
| B. | A is false but R is true |
| C. | 0.25 |
| D. | 0.125 |
| Answer» D. 0.125 | |
| 769. |
The equivalent inductance seen at terminals A - B is |
| A. | 14 H |
| B. | 20 H |
| C. | 10 H |
| D. | 4 H |
| Answer» B. 20 H | |
| 770. |
If a fuse is higher than required current rating is employed in a circuit, it will |
| A. | blow more frequently since it carries more current |
| B. | afford better protection to the circuit |
| C. | seriously overload the circuit |
| D. | lead to larger maintenance cost |
| Answer» D. lead to larger maintenance cost | |
| 771. |
Two resistances of 2 Ω each are connected in series. A shunt having zero resistance is connected across the combination. The overall resistance will be |
| A. | 0.5 Ω |
| B. | zero |
| C. | may lie any where in s plane |
| D. | may have positive or negative real part |
| Answer» E. | |
| 772. |
The following table gives some Laplace transforms and the functionsf(t)   F(s)1.δ(t)   s2. u(t)   1/s3. tu(t)   2/s24. t2u(t)   2s3Of these the correctly matched pairs are |
| A. | 2 and 4 |
| B. | 1 and 4 |
| C. | 2 and 4 |
| D. | 1 and 2 |
| Answer» B. 1 and 4 | |
| 773. |
The maximum current and voltage ratings for a 0.5 W, 10 kW resistor are |
| A. | 7.07 mA and 70.7 V |
| B. | 70.7 mA and 70.7 V |
| C. | 0.707 mA and 70.7 V |
| D. | 7.07 mA and 70.7 x 103 V |
| Answer» B. 70.7 mA and 70.7 V | |
| 774. |
Two voltages are v1= 100 sin (ωt + 15°) and v2 = 60 cosωt, then |
| A. | v2 is leading v1 by 75° |
| B. | v2 is lagging v1 by 15° |
| C. | 4∠64° |
| D. | 4∠8° |
| Answer» D. 4‚à†8¬∞ | |
| 775. |
A parallel connection of circuit is at below resonance circuit behave as |
| A. | RLC |
| B. | resistive only |
| 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 | |
| 776. |
In an RC impedance function |
| A. | the highest critical frequency is a pole or zero |
| B. | the highest critical frequency is a pole at s = 0 |
| C. | the statement is true |
| D. | the statement is false |
| Answer» C. the statement is true | |
| 777. |
If the transmission parameters of the given networks are A = C = 1, B = 2 and D = 3, then the value of Zm is |
| A. | 12/13 Ω |
| B. | 13/12 Ω |
| C. | 3 Ω |
| D. | 4 Ω |
| Answer» B. 13/12 Œ© | |
| 778. |
For a high pass filter, β = p in attenuation band. |
| A. | only poles but no zeros on imaginary axis of s plane |
| B. | only zeros but no poles on imaginary axis of s plane |
| Answer» C. | |
| 779. |
L/C has the dimension of |
| A. | time |
| B. | capacitance |
| C. | inductance |
| D. | resistance |
| Answer» E. | |
| 780. |
In a series R-L-C circuit at the resonant frequency the |
| A. | impedance is maximum |
| B. | voltage is maximum |
| C. | 45° |
| D. | 0° |
| Answer» B. voltage is maximum | |
| 781. |
Two wires A and B have the same cross-section area and are made of the same material. RA = 600 Ω and RB = 100 Ω. The number of times A is longer than B is |
| A. | 6 |
| B. | 2 |
| C. | 4 |
| D. | 5 |
| Answer» B. 2 | |
| 782. |
Assertion (A): In a circuit having high inductance, reactive power may be more than apparent power.Reason (R): Reactive power = VI sin θ. |
| 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. | |
| 783. |
In using KCL it is necessary that current leaving a node is written as negative. |
| A. | 1 |
| B. | |
| C. | 1 mA |
| D. | 27.386 mA |
| Answer» C. 1 mA | |
| 784. |
If the numerator of Z(s) is one degree higher than denominator, Z(s) has a pole at infinity. |
| A. | 1 |
| B. | |
| C. | both fc and f‚àû will increase |
| D. | both fc and f‚àû will decrease |
| Answer» B. | |
| 785. |
The Z parameter of the following T-network is |
| A. | |
| B. | not possible |
| C. | 1 |
| Answer» B. not possible | |
| 786. |
Two capacitors of 1 μF and 2 μF are connected in series across a 10 V dc battery. After the capacitors have been charged, the charges across the two capacitors will be |
| A. | 10 μC each |
| B. | 20 μC each |
| C. | 10 μC and 20 μC |
| D. | 20 μC and 10 μC |
| Answer» C. 10 ŒºC and 20 ŒºC | |
| 787. |
For a voltage transfer function H(s), realizable by RLC network, the following statements are made H(s) cannot have a pole at s = 0H(s) cannot have a pole at s = ± j4H(s) cannot have a pole at s = ∞H(s) cannot have a pole at s = + 2 Of these statements |
| A. | 3 and 4 are correct |
| B. | 2 and 4 are correct |
| C. | 1 and 2 are correct |
| D. | 1 and 3 are correct |
| Answer» B. 2 and 4 are correct | |
| 788. |
Assertion (A): The dual of a circuit can be drawn by window-dot method. Reason (R): The principle of duality is of great help in circuit analysis. |
| A. | A is true but R is false |
| B. | A is false but R is true |
| C. | used short pieces of wire |
| D. | goes only a short distance |
| Answer» C. used short pieces of wire | |
| 789. |
In a series L-C circuit fed by ac voltage, voltage drops across L and C are 40 V and 30 V respectively. The supply voltage is |
| A. | 70 V |
| B. | 10 V |
| C. | 50 V |
| D. | 1.333 V |
| Answer» D. 1.333 V | |
| 790. |
Maximum power from a source having internal resistance Ri is delivered to a resistive load RL, if |
| A. | Ri = RL2 |
| B. | Ri = RL |
| C. | 103 W |
| D. | 106 W |
| Answer» E. | |
| 791. |
In an RC series circuit excited by dc voltage E, the current at t = 0 is |
| A. | E/R |
| B. | E/C |
| C. | zero |
| D. | infinity |
| Answer» B. E/C | |
| 792. |
Assertion (A): In a parallel circuit with three branches having R, L and C respectively and fed by a step current I, the current through inductance is always zero.Reason (R): The time constant of R-L circuit is L/R. |
| A. | A is true but R is false |
| B. | A is false but R is true |
| C. | may be 50% or less than 50% |
| D. | is 50% |
| Answer» E. | |
| 793. |
The internal impedance of a source is 3 + j 7 Ω. For maximum power transfer, load impedance should be |
| A. | 3 + j 7 Ω |
| B. | 3 - j 7 Ω |
| C. | 7 + j 3 Ω |
| D. | 7 - j 3 Ω |
| Answer» C. 7 + j 3 Œ© | |
| 794. |
S is open for a long time and steady state is reached S is closed at t = 0. Let iL the current in the inductor At t = 0+, is given by |
| A. | -2 |
| B. | -1 |
| C. | -4 |
| D. | -‚àû |
| Answer» C. -4 | |
| 795. |
The resistance RAB in the circuit is |
| A. | 10 Ω |
| B. | 12 Ω |
| C. | 9 Ω |
| D. | 3 Ω |
| Answer» D. 3 Œ© | |
| 796. |
Among the filter, Bessel, Butterworth and chebyshev, the filter with maximally flat response is |
| A. | all |
| B. | butterworth |
| C. | bessel |
| D. | butterworth, Chebyshev |
| Answer» D. butterworth, Chebyshev | |
| 797. |
The magnitude response of a normalised Butterworth low pass filter is |
| A. | linear starting with value of unity at zero frequency and 0.707 at cut off frequency |
| B. | non linear all through but with values of unity at zero frequency and 0.707 at cut off frequency |
| C. | linear upto cut off frequency and nonlinear thereafter |
| D. | nonlinear upto cut off frequency and linear thereafter |
| Answer» B. non linear all through but with values of unity at zero frequency and 0.707 at cut off frequency | |
| 798. |
Two coils having self inductances of 10 mH and 40 mH are mutually coupled. The maximum possible mutual inductance is |
| A. | 40 mH |
| B. | 20 mH |
| C. | 10 mH |
| D. | 5 mH |
| Answer» C. 10 mH | |
| 799. |
Electric shock is |
| A. | sometimes fatal |
| B. | always disfiguring |
| C. | a zero in left half plane |
| D. | a zero in right half plane |
| Answer» D. a zero in right half plane | |
| 800. |
An ideal voltage source can not be converted into an equivalent current source. |
| A. | 1 |
| B. | |
| C. | R |
| D. | R + jωL |
| Answer» B. | |