Explore topic-wise MCQs in Electronics & Communication Engineering.

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.

1.

For a high pass filter, β = p in attenuation band.

A. True
B. False
Answer» C.
Discussion
2.

In attenuation band, β is an odd multiple of p.

A. True
B. False
Answer» B. False
Discussion
3.

For a series RLC circuit bandwidth is ω2 - ω1 = R/2L.

A. True
B. False
Answer» C.
Discussion
4.

In a series RC circuit Z = (R2 + ω2C2)0.5.

A. True
B. False
Answer» C.
Discussion
5.

As per Euler's identity ejωt = cos ωt + j sin ωt

A. True
B. False
Answer» B. False
Discussion
6.

μ0 = 8.85 x 10-12F/m.

A. True
B. False
Answer» B. False
Discussion
7.

Resistivity of semiconductors is around 100 Ω-m.

A. True
B. False
Answer» C.
Discussion
8.

Assertion (A): In series R-L-C circuit, the current may lead or lag the voltage depending on the value of R.Reason (R): Phase angle of an R-L series circuit is tan-1 (ωL/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» E.
Discussion
9.

Assertion (A): If A = 0.5 ∠ 20°, A2 = 0.25 ∠ 40°.Reason (R): When drawing a phasor diagram, sinusoids may have the same or different 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» D. A is false but R is true
Discussion
10.

Assertion (A): When capacitor is fed by a dc voltage given a capacitor behaves as short circuit at t = 0 and open circuit at f = ∞.Reason (R): The impedance of a capacitor is

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
Discussion
11.

Assertion (A): is positive real.Reason (R): For a positive real function Re[H(jω)] ≥ 0 for 0 ≤ ω ≤ ∞.

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.
Discussion
12.

Assertion (A): Laplace transform of f(t) = e-at sin ωt is Reason (R): If Laplace transform of f(t) is F(s), then Laplace transform of e-at f(t) is F(s + a).

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
Discussion
13.

If resistance is 20 Ω and inductance is 2 H in a R-L series circuit, then time constant of this will be

A. 0.001 s
B. 0.1 s
C. 10 s
D. 100 s
Answer» C. 10 s
Discussion
14.

Consider the following statements for a driving point function F(jω): Re F(jω) is an even function of ω and is 0 or positive for all values of ω.Im F(jω) is an even function of ω and is 0 or positive for all values of ω.Re F(jω) is an odd function of ω and is 0 or negative for all values of ω.Re F(s) = 0 for Re s = 0. Which one of the statements given above is/are correct?

A. 1 only
B. 1 and 4
C. 2, 2 and 4
D. 4 only
Answer» B. 1 and 4
Discussion
15.

Consider the following expression for the driving point impedance It represent on LC circuitIt represent on RLC circuitIt has poles lying on the jω axisIt has a pole at infinite frequency and a zero at zero frequency. Which one fo the statement given above are correct?

A. 2 and 4
B. 1 and 3
C. 1 and 4
D. 2 and 3
Answer» C. 1 and 4
Discussion
16.

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. 120
B. 12
C. 1200
D. 10
Answer» B. 12
Discussion
17.

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. 1 A
C. 2 A
D. 3 A
Answer» B. 1 A
Discussion
18.

In the circuit shown in the given figure, power dissipated in the 5 Ω resistor is

A. zero
B. 80 W
C. 125 W
D. 405 W
Answer» E.
Discussion
19.

In the given circuit, V1 = 40 V when R is 10 Ω. When R is zero, the value of V2 will be

A. 40 V
B. 30 V
C. 20 V
D. 10 V
Answer» B. 30 V
Discussion
20.

The impedance matrices of two, two-port network are given by and . If these two networks are connected in series, the impedance matrix of the resulting two-port network will be

A. [A].
B. [B].
C. [C].
D. indeterminate
Answer» C. [C].
Discussion
21.

In the above circuit, if the power dissipated in the 6 Ω resistor is zero then V is

A. 20 2∠ 45°
B. 20 ∠ 30°
C. 20 ∠ 45°
D. 20 2∠ 30°
Answer» B. 20 ∠ 30°
Discussion
22.

Which one of the following theorem can be conveniently used to calculate the power consumed by the 10 Ω resistor in the network shown in the above figure?

A. Thevenin's theorem
B. Maximum power transfer theorem
C. Millman's theorem
D. Superposition theorem
Answer» E.
Discussion
23.

The ac bridge shown in the figure is balanced if and Z4 is equal to

A. [A].
B. [B].
C. [C].
D. [D].
Answer» C. [C].
Discussion
24.

A two-port network is represented by ABCD parameters given byIf port is terminated by RL, then input impedance seen at port 1 is given by

A. [A].
B. [B].
C. [C].
D. [D].
Answer» E.
Discussion
25.

As x is increased from - ∞ to ∞, the function

A. monotonically increases
B. monotonically decreases
C. increases to a maximum value and then decrease
D. decreases to a minimum value and then increases
Answer» B. monotonically decreases
Discussion
26.

A low-pass filter frequency responce H (jω) = A (ω) ejΦ(ω) does not produce any phase distortion, if

A. A(ω) = Cω2, Φ (ω) = kω3
B. A(ω) = Cω2, Φ (ω) = kω
C. A(ω) = Cω2, Φ (ω) = kω2
D. A(ω) = C, Φ (ω) = kω-1
Answer» C. A(ω) = Cω2, Φ (ω) = kω2
Discussion
27.

In a series RLC circuit, R = 2 kΩ, L = 1H and The resonant frequency is

A. 2 x 104 Hz
B. 1/p x 104 Hz
C. 104 Hz
D. 2p x 104 Hz
Answer» C. 104 Hz
Discussion
28.

For the circuit shown in the figure, the initial conditions are zero. Its transfer function is

A. [A].
B. [B].
C. [C].
D. [D].
Answer» C. [C].
Discussion
29.

For the lattice circuit shown in the figure Za = j2 Ω and Zb = 2 Ω. The values of the open circuit impedance parameters Z = are

A. [A].
B. [B].
C. [C].
D. [D].
Answer» E.
Discussion
30.

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°)
Discussion
31.

An input voltage V(t) = 10 2 cos (t + 10°) + 10 3 cos (2t + 10°)V is applied to a series combination of resistance R = 1 kΩ inductance L = 1H. The resulting steady-state current i(t) in ampere is

A. 10 cos (t + 55°) + 10 cos (2t + 10° tan-12)
B. 10 cos (t + 55°) + 103/2 cos (2t + 55°)
C. 10 cos (t - 35) + 10 cos (2t + 10° - tan-12)
D. 10 cos (t - 35) + 103/2 cos (2t + 35°)
Answer» D. 10 cos (t - 35) + 103/2 cos (2t + 35°)
Discussion
32.

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 Ω
Discussion
33.

The Laplace transform of i(t) is given by As t → ∞ the value of i(t), tends to

A. 0
B. 2
C. 1
D. ∞
Answer» C. 1
Discussion
34.

A source of angular frequency 1 rad sec has a source impedance consisting of 1 Ω resistance in series with 1 H inductance. The load that will obtained the maximum power transfer is

A. 1 Ω resistance
B. 1 Ω resistance in parallel with 1 H inductance
C. 1 Ω resistance in series with 1 F capacitor
D. 1 Ω resistance in parallel with 1 F capacitor
Answer» D. 1 Ω resistance in parallel with 1 F capacitor
Discussion
35.

In an infinite ladder Ckt as shown above each resistance of rΩ then RAB

A. ∞
B. [B].
C. 1.61 Ω
D. none
Answer» D. none
Discussion
36.

An infinite ladder is constructed with 1 Ω and 2 Ω resistors shown below.

A. 8.18 A
B. 0 A
C. 9 A
D. can't determined
Answer» D. can't determined
Discussion
37.

A 10 μF capacitor is charged from a 5 volt source through a resistance of 10 kΩ. The charging current offer 35 m sec. If the initial voltage on C is - 3 V is

A. 0.56 mA
B. 5.6 mA
C. 6 mA
D. 5 μA
Answer» B. 5.6 mA
Discussion
38.

A series LCR circuit consisting of R = 20 Ω, | XL | = 20 Ω and | XC | = 20 Ω, connected across an A.C. supply of 200 V rms. The rms voltage across the capacitor is

A. 100 ∠ 45
B. 400 ∠ -90°
C. 400 ∠ +90°
D. 100 ∠ -45
Answer» C. 400 ∠ +90°
Discussion
39.

The transfer function H(s) of a system is given by Given that understeady state conditions, the sinusoidal I/P and 0/P are respectively x(t) = cos 2t and y(t) = cos (2t + Φ), then the angle Φ will be

A. 45°
B. 0°
C. -45°
D. -90°
Answer» D. -90°
Discussion
40.

A loudspeaker transformer has a turns ratio of 20 : 1. The speaker impedance is 20Ω. Primary impedance of transformer is

A. 10 K
B. 8 K
C. 20 K
D. 0.5 K
Answer» C. 20 K
Discussion
41.

The current through a 1 mH inductance is i(t) = 2.56 x 10-2 - 4 x 103 t for 2 ≤ t ≤ 20 μ sec. The voltage across the inductor is

A. 4
B. 8
C. 0
D. 8 x 103
Answer» B. 8
Discussion
42.

Calculate i(t) for t ≥ 0, assuming the switch has been in position A for a long time at t = 0, the switch is moved to position B.

A. 1 + e-5 x 103t
B. e-5 x 103t
C. 1.11 e-5 x 103t
D. 1.11 (1 - e-5 x 103t)
Answer» D. 1.11 (1 - e-5 x 103t)
Discussion
43.

A 20 Ω resistor, a 1H inductor and 1μF capacitor are connected in parallel the combination is driven by a unit step current. Under the steady state, source current flows through

A. inductor
B. capacitor
C. resistor
D. all
Answer» B. capacitor
Discussion
44.

In the circuit, Vs = 10 cos ωt, power drawn by the 4Ω resistor is 8 watt. The power factor is

A. 1
B. 0.5
C. 0.85
D. 0
Answer» D. 0
Discussion
45.

A parallel RLC circuit has ω0 = 106 and Q = 30, Given C = 30 pF, the value of R is

A. 0
B. 1 μΩ
C. 2 MΩ
D. 1 MΩ
Answer» E.
Discussion
46.

Given Is = 20 A, Vs = 20 V, the current I in the 3 Ω resistance is given by

A. 4 A
B. 8 A
C. 2 A
D. 16 A
Answer» B. 8 A
Discussion
47.

Given , and f(t)t → ∞ is . The value of k is

A. 3/16
B. 16/3
C. 3
D. 1/4
Answer» C. 3
Discussion
48.

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. [C].
D. 0
Answer» C. [C].
Discussion
49.

In the circuit shown, the steady state is reached with S open S is closed at t = 0, the current I in the 1 Ω resistor connected is to be determined at t = 0+ is given by

A. 1
B. 2
C. 3
D. 4/3
Answer» B. 2
Discussion
50.

In the circuit shown in figure, for different values of R, the values of V and I are given. Other elements remaining the same. when R = ∞, V = 5 volt R = 0, I = 2.5 AR = 3 Ω, the value of V is given by

A. 1 V
B. 2 V
C. 3 V
D. 5 V
Answer» D. 5 V
Discussion