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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.
| 351. |
A system function H(s) = s / (s²+4s+100) the resonant frequency in rad/sec and bandwidth in rad/sec. is given by |
| A. | 10 and 1 |
| B. | 10, 4 |
| C. | 100, 5 |
| D. | 10, 10 |
| Answer» C. 100, 5 | |
| 352. |
In the figure 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 | |
| 353. |
For the mechanical system of figure, the correct differential equation is (where x = displacement in m, M = mass in kg, B = damping constant, N - sec/m K is spring constant, N/m and F = force, newton). |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 354. |
1. P(s) = s⁴ + s³ + 2s² + 4s + 32. Q(s) = s⁴ + 2s³ + s Which one of the following statements in correct for above P(s) and Q(s) polynomials? |
| A. | Both P(s) and Q(s) are Hurwitz |
| B. | Both P(s) and Q(s) are non-Hurwitz |
| C. | P(s) is Hurwitz but Q(s) is non-Hurwitz |
| D. | P(s) is non-Hurwitz but Q(s) is Hurwitz |
| Answer» D. P(s) is non-Hurwitz but Q(s) is Hurwitz | |
| 355. |
In an R-C circuit, the impedance is 40 Ω at a frequency of 100 Hz. At 200 Hz the impedance should be |
| A. | 40 Ω |
| B. | 80 Ω |
| C. | 20 Ω |
| D. | more than 20 Ω but less than 40 Ω |
| Answer» E. | |
| 356. |
If |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 357. |
To find current in a resistance connected in a network, Thevenin's theorem is used VTH = 20 V and RTH = 5 Ω. The current through the resistance |
| A. | is 4 A |
| B. | is 4 A or less |
| C. | is less than 4 A |
| D. | may be 4 A or less or more than 4 A |
| Answer» D. may be 4 A or less or more than 4 A | |
| 358. |
Z-matrix for the network shown in the given figure is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 359. |
A series RLC circuit is supplied from a variable frequency ac source. The resonant frequency is ω₀. The voltage across C is maximum at a frequency |
| A. | equal to ω₀ |
| B. | slightly less than ω₀ |
| C. | slightly more than ω₀ |
| D. | none of the above |
| Answer» C. slightly more than ω₀ | |
| 360. |
The polar plot of P (jω) = 45° as ω varies from -∞ to ∞ is |
| A. | a straight line parallel to x-axis |
| B. | a straight line parallel to y-axis |
| C. | a line passing through origin and inclined at 45° |
| D. | a line in first quadrant passing through origin and inclined at 45° to positive x-axis |
| Answer» C. a line passing through origin and inclined at 45° | |
| 361. |
If f(t) = δ(t), F(s) = |
| A. | 1/s² |
| B. | 1/s |
| C. | 1 |
| D. | s |
| Answer» B. 1/s | |
| 362. |
The integral of a unit step function is |
| A. | an impulse function |
| B. | a ramp function |
| C. | a ramp function of slope 1 |
| D. | none of these |
| Answer» D. none of these | |
| 363. |
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 | |
| 364. |
The differential equation for the current i(t) in the circuit of the figure is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» D. D | |
| 365. |
A series RL circuit is initially relaxed. A step voltage is applied to the circuit. If t is the time constant of the circuit, the voltage across R and L will be same at time t equal to |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 366. |
In liquids charge carriers are electrons only. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» C. May be True or False | |
| 367. |
If A = 3 + j1, A⁴ = |
| A. | 3.16 ∠18.4° |
| B. | 100 ∠73.72° |
| C. | 100 ∠18.4° |
| D. | 3.16 ∠73.22° |
| Answer» C. 100 ∠18.4° | |
| 368. |
A circuit is fed by two sources of the same frequency and values 100 ∠0° V and 20 ∠30°V. The current in a particular branch is 5 ∠19° A. If the magnitudes of the sources and changed to 200 ∠0° V and 40 ∠30° V, the current in that branch should be |
| A. | 5 ∠19° A |
| B. | 10 ∠19° A |
| C. | 10 ∠38° A |
| D. | 10 ∠9.5° A |
| Answer» C. 10 ∠38° A | |
| 369. |
Which of the following graphs in figure correctly represents the variation of capacitive reactance with frequency? |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» D. D | |
| 370. |
In an ideal current source, the source resistance is zero. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» C. May be True or False | |
| 371. |
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 | |
| 372. |
Assertion (A): The s domain impedance of a series R-L circuit is R + sL irrespective of initial conditions.Reason (R): Complex frequency s = σ + jω. |
| 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. | |
| 373. |
For an m-derived filter, attenuation is infinite when f = f∞. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 374. |
If F1(s) and F2(s) are two positive real functions, then the function which is always positive real is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 375. |
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^(-1)2) |
| B. | 10 cos (t + 55°) + 10√3/2 cos (2t + 55°) |
| C. | 10 cos (t - 35) + 10 cos (2t + 10° - tan^(-1)2) |
| D. | 10 cos (t - 35) + 10√3/2 cos (2t + 35°) |
| Answer» D. 10 cos (t - 35) + 10√3/2 cos (2t + 35°) | |
| 376. |
In the circuit of figure, Thevenin's resistance is 10 Ω |
| A. | 25 Ω |
| B. | 10 Ω |
| C. | 13.33 Ω |
| D. | 6 Ω |
| Answer» C. 13.33 Ω | |
| 377. |
The time constant of the network shown in figure is |
| A. | RC |
| B. | 3 RC |
| C. | 2RC/3 |
| D. | 3RC/2 |
| Answer» D. 3RC/2 | |
| 378. |
In a linear bilateral passive element two port which of the following holds for z parameters? |
| A. | z11 = z22 |
| B. | z12 z22 = z11 z22 |
| C. | z11 z12 = z22 z21 |
| D. | z12 = z21 |
| Answer» E. | |
| 379. |
Consider the following statements :1. Tellegen's theorem is applicable to any lumped networks.2. The reciprocity theorem is applicable to linear bilateral networks.3. Thevenin's theorem is applicable to two- terminal linear active networks.4. Norton's theorem is applicable to two-terminal linear active networks. Which of these statement are correct? |
| A. | 1, 2, and 3 |
| B. | 1, 2 and 4 |
| C. | 1, 2, 3 and 4 |
| D. | 3 and 4 |
| Answer» D. 3 and 4 | |
| 380. |
Two capacitors of 1 μF and 2 μF capacitance are connected in parallel across a 30 V dc battery. After the capacitors have been charged, the charges across the two capacitors will be |
| A. | 30 μC each |
| B. | 60 μC each |
| C. | 30 μC and 60 μC respectively |
| D. | 60 μC and 30 μC respectively |
| Answer» D. 60 μC and 30 μC respectively | |
| 381. |
The frame of electric motor is connected to three plates having earthing resistance of 10 Ω, 20 Ω and 30 Ω respectively. The materials of the three plates are copper, aluminium and iron respectively. The percentage of energy dissipated by 10 Ω earthing plate |
| A. | is more than 50% of total energy |
| B. | is less than 50% of total energy |
| C. | depends on the materials of the three plates |
| D. | may be more or less than 50% of total energy |
| Answer» B. is less than 50% of total energy | |
| 382. |
An RLC series circuit is underdamped. To make it overdamped, the value of R |
| A. | has to be increased |
| B. | has to be decreased |
| C. | has to be increased to infinity |
| D. | has to be reduced to zero |
| Answer» B. has to be decreased | |
| 383. |
The first and the last critical frequencies (singularities) of a driving point impedance function of a passive network having two kind of elements, are a pole and a zero respectively. The above property will be satisfied by |
| A. | RL network only |
| B. | RC network only |
| C. | LC network only |
| D. | RC as well as RL network |
| Answer» C. LC network only | |
| 384. |
Q of a coilA. increases with Q increasing frequencyB. varies linearly with frequencyC. increase with increasing frequency because R increases at high frequencyD. decrease after the peak frequency because R increases at H.F. The correct statements are |
| A. | A, B |
| B. | C, D |
| C. | A, C |
| D. | B, D |
| Answer» C. A, C | |
| 385. |
If operator 'a' = 1 ∠120° then (1 - a) = |
| A. | √3 |
| B. | √3 ∠ - 30° |
| C. | √3 ∠ + 30° |
| D. | √3 ∠60° |
| Answer» C. √3 ∠ + 30° | |
| 386. |
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. | 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 | |
| 387. |
Consider the network graph shown in the figure which one of the following is NOT a 'tree' of graph |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 388. |
A series RL circuit is excited by a voltage v(t) = Vm sin (ωt + Φ). The transient current will be zero if |
| A. | Φ = 0 |
| B. | ω = 0 |
| C. | Φ = tan¯¹ (ωL/R) |
| D. | ω - tan¯¹ (ωL/R) = p/2 |
| Answer» D. ω - tan¯¹ (ωL/R) = p/2 | |
| 389. |
For the network of figure, [z] matrix is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» D. D | |
| 390. |
If Z(s) = (s² + 1)/s , the network has |
| A. | 1 H inductor and 1 F capacitor in parallel |
| B. | 1 H inductor and 1 F capacitor in series |
| C. | 1 H inductor and 1 Ω resistor in series |
| D. | 1 H inductor and 1 Ω resistor in parallel |
| Answer» C. 1 H inductor and 1 Ω resistor in series | |
| 391. |
If each branch of a Delta circuit has impedance √3 Z then each branch of the equivalent Y circuit has impedance. |
| A. | Z/√3 |
| B. | 3 Z |
| C. | 3/√3 Z |
| D. | Z/3 |
| Answer» B. 3 Z | |
| 392. |
The circuit shown in the figure has initial current iL(0) = 1A through the inductor and an initial voltage vc(0) = 1 V across the capacitor. For input v(t) = U(t) the Laplace transform of the current i(t) for t ≥ 0 is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 393. |
An RLC series circuit is excited by 200 V, 100 Hz supply. The current is 20 A. If R = 10 Ω, XL = 50 Ω, XC is |
| A. | 10 Ω |
| B. | 14.14 Ω |
| C. | 7.07 Ω |
| D. | 50 Ω |
| Answer» E. | |
| 394. |
For H(s) to be positive real, the condition Re[H(jω)] ≥ 0 for 0 ≤ ω ≤ ∞ is |
| A. | a necessary condition |
| B. | a sufficient condition |
| C. | a necessary and sufficient condition |
| D. | is not a necessary condition |
| Answer» B. a sufficient condition | |
| 395. |
For a superconductor, magnetisation M in a field H is |
| A. | extremely small |
| B. | - H |
| C. | - I |
| D. | zero |
| Answer» C. - I | |
| 396. |
An RL series circuit has an impedance of 20 Ω when frequency is 25 Hz. At f= 50 Hz, the impedance will be |
| A. | 40 Ω |
| B. | 20 Ω |
| C. | less than 40 W but more than 20 Ω |
| D. | less than 20 W but more than 10 Ω |
| Answer» D. less than 20 W but more than 10 Ω | |
| 397. |
An m derived low pass filter has fc = 1000 Hz, f∞ = 1250 Hz and m = 0.6. If m is increased, then |
| A. | both fc and f∞ will increase |
| B. | both fc and f∞ will decrease |
| C. | fc will remain constant but f∞ will decrease |
| D. | fc will remain constant but f∞ will increase |
| Answer» E. | |
| 398. |
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 Ω | |
| 399. |
Thevenin's theorem is used to find current in a branch of a network. It is now desired to find current in another branch of the network |
| A. | the same Thevenin's circuit can be used |
| B. | the same Thevenin's circuit with some modification can be used |
| C. | it is necessary to find new Thevenin's circuit |
| D. | either (b) or (c) |
| Answer» D. either (b) or (c) | |
| 400. |
As per Euler's identity e^(jωt) = cos ωt + j sin ωt |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |