MCQOPTIONS
Saved Bookmarks
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.
| 201. |
In figure, the voltage V1 = 4∠0 V. The source voltage V2 is |
| A. | 8 - j8 volts |
| B. | 4 - j4 volts |
| C. | 8 - j4 volts |
| D. | 8 - j16 volts |
| Answer» D. 8 - j16 volts | |
| 202. |
The drift velocity of electrons is |
| A. | very small as compared to speed of light |
| B. | equal to speed of light |
| C. | almost equal to speed of light |
| D. | half the speed of light |
| Answer» B. equal to speed of light | |
| 203. |
A series RL circuit is excited by a voltage v(t) = Ve^(-at) such that a = R/L. Then the circuit current is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 204. |
In an R-L circuit excited by a battery of voltage E, the current and voltage across resistor are 1- e^-t and 2(1 - e^-t) respectively. If there were an initial current of 2 A in the inductance, the voltage across resistance would have been |
| A. | 1 - e^-t |
| B. | 2 - 2e^-t |
| C. | 2 + 2e^-t |
| D. | 4 - 4e^-t |
| Answer» D. 4 - 4e^-t | |
| 205. |
Which of the following is/are correct? The circuit shown in the figure.1. is reciprocal2. has Z11 = 2, Z22 = 23. has Z11 = 4, Z22 = 24. has Z11 = 0, Z22 = 2Select the correct answer using the code given below: |
| A. | 1 and 3 |
| B. | 1 and 2 |
| C. | 1 and 4 |
| D. | 3 only |
| Answer» B. 1 and 2 | |
| 206. |
The transfer function of a system is given by H(s) = 1/s² (s - 2). The impulse response of the system is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 207. |
A two branch parallel tuned circuit has a coil of resistance 100 Ω and inductance 0.005 H in one branch and 10 nF capacitor in the second branch. At resonance frequency, the dynamic resistance is |
| A. | 1 Ω |
| B. | 10 Ω |
| C. | 100 Ω |
| D. | more than 100 Ω |
| Answer» E. | |
| 208. |
A series RC circuit has R = 5 Ω and C = 10 μF. The current in the circuit is 5 sin 20000t. The applied voltage is |
| A. | 25√2 sin (20000t + 45°) |
| B. | 25√2 sin (20000t - 45°) |
| C. | 252 sin 20000t |
| D. | 25√2 sin (20000t - 90°) |
| Answer» C. 252 sin 20000t | |
| 209. |
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. | |
| 210. |
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. | |
| 211. |
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 | |
| 212. |
The response of a network is shown in figure. Which of following represents location of poles? |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 213. |
A parallel RLC circuit with R1 = 20, L1 = 1/100 and C1 = 1/200 is scaled giving R2 = 10⁴, L2 = 10¯⁴ and C2, the value of C2 is |
| A. | 0.10 nF |
| B. | 0.3 nF |
| C. | 0.2 nF |
| D. | 0.4 nF |
| Answer» D. 0.4 nF | |
| 214. |
What are the ABCD parameters of the single elements circuit given below? |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 215. |
In f(t) = δ(t - T), F(s) = |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» D. D | |
| 216. |
A constant k high pass p section has a characteristic impedance of 300 Ω at f = ∞ . At f = fc, the characteristic impedance will be |
| A. | zero |
| B. | ∞ |
| C. | 300 Ω |
| D. | more than 300 Ω |
| Answer» C. 300 Ω | |
| 217. |
Flux linkages ψ and voltages v are related as |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 218. |
A 3 phase balanced supply feeds 3 phase unbalanced load. Power supplied to the load can be measured by using1. 2 wattmeter2. one wattmeter3. 3 wattmeter Which of the above statements is correct? |
| A. | 1 and 2 |
| B. | 1 and 3 |
| C. | 2 and 3 |
| D. | 3 alone |
| Answer» C. 2 and 3 | |
| 219. |
If the π and T circuits in figure are equivalent, then R1, R2, R3 respectively are |
| A. | 9 Ω, 6 Ω, 6 Ω |
| B. | 6 Ω, 6 Ω, 9 Ω |
| C. | 9 Ω, 6 Ω, 9 Ω |
| D. | 6 Ω, 9 Ω, 6 Ω |
| Answer» C. 9 Ω, 6 Ω, 9 Ω | |
| 220. |
The inverse Fourier transform of following is |
| A. | sin ωt |
| B. | cos ωt |
| C. | sgn (t) |
| D. | u (t) |
| Answer» D. u (t) | |
| 221. |
As x is increased from - ∞ to ∞, the following 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 | |
| 222. |
A series RLC circuit is overdamped when |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 223. |
In the following circuit, i(t) under steady state is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 224. |
A battery charger can drive a current of 5A with 1Ω resistance connected at its output. If it can charge 2 V battery at 7 A rate, its Thevenin's equivalent circuit will be |
| A. | 7.5 in series with 0.5 Ω resistance |
| B. | 1.25 V in series with 1.5 Ω resistance |
| C. | 7.5 V in parallel with 0.5 Ω resistance |
| D. | 12.5 V in parallel with 1.5 Ω resistance |
| Answer» B. 1.25 V in series with 1.5 Ω resistance | |
| 225. |
A minimum function has |
| A. | poles and zeros on imaginary axis of s plane |
| B. | no poles or zeros on imaginary axis of s plane |
| C. | only poles but no zeros on imaginary axis of s plane |
| D. | only zeros but no poles on imaginary axis of s plane |
| Answer» D. only zeros but no poles on imaginary axis of s plane | |
| 226. |
An RLC series circuit has R = 1 Ω, L = 1 H, C = 1 F. The damping ratio is |
| A. | More than 1 |
| B. | 1 |
| C. | 0.5 |
| D. | Zero |
| Answer» D. Zero | |
| 227. |
The dc voltage applied to an R-L series circuit is suddenly changed from V1 to V2. The expression for transient current is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» D. D | |
| 228. |
The average value of delayed full wave rectified sine wave (figure) is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» D. D | |
| 229. |
If Δs is an element of area and ΔI is the current through this element, current density J is defined as |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 230. |
A magnetic circuit has an iron length of 20 cm and air gap length 0.1 cm. If μᵣ = 200 then |
| A. | mmf for iron and air gap are equal |
| B. | mmf for iron is much less than that for air gap |
| C. | mmf for iron is much more than that for air gap |
| D. | either (a) or (c) |
| Answer» B. mmf for iron is much less than that for air gap | |
| 231. |
The driving point impedance of a network is given by following equation. The number of energy storing elements in the network is |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 232. |
The voltage in a circuit follows the law v = 100 sin ωt if the frequency is 25 Hz, how long will it take for the voltage to rise to 50 volts? |
| A. | 1/150 s |
| B. | 1/100 s |
| C. | 1/300 s |
| D. | 1/600 s |
| Answer» D. 1/600 s | |
| 233. |
Three capacitors each 9 μF are connected in delta. The value of each capacitor in equivalent star connection is |
| A. | 3 μF |
| B. | 6 μF |
| C. | 27 μF |
| D. | 81 μF |
| Answer» D. 81 μF | |
| 234. |
Two coupled coils A and B are connected in series. The total inductances in series aiding and series opposing connections are LA and LB. The mutual inductance M is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 235. |
The Q factor of a series RLC circuit is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 236. |
If B = 4 + j3, (B)^1/3 = |
| A. | 2 ∠30° |
| B. | 2 ∠36.87° |
| C. | 1.71 ∠12.3° |
| D. | 1.71 ∠30° |
| Answer» C. 1.71 ∠12.3° | |
| 237. |
In solid dielectrics the rate of deterioration doubles for every 10-12°C rise in temperature. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 238. |
An excitation is applied to a system at t = T, and its response is zero for -∞ < t < T, such a system is |
| A. | non-causal system |
| B. | Stable system |
| C. | causal system |
| D. | unstable system |
| Answer» D. unstable system | |
| 239. |
For the ladder network of figure, open circuit driving point impedance at port 1 = |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 240. |
In a one port network Z(s) = s+2/s+3 . It is excited by a unit step current. The initial and final values of voltage across the network impedance are |
| A. | 1/2 and 3 |
| B. | 2/3 and 1 |
| C. | 0 and 2/3 |
| D. | 1 and 0 |
| Answer» B. 2/3 and 1 | |
| 241. |
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 | |
| 242. |
In a series RLC circuit the phase angle θ of impedance Z ∠θ is positive. The circuit will behave as |
| A. | resistive circuit |
| B. | RC circuit |
| C. | RL circuit |
| D. | either RL or RC circuit |
| Answer» C. RL circuit | |
| 243. |
In a 5.6 ohms, ± 10% carbon composition resistor, the colour of the third strip from extreme left is |
| A. | golden |
| B. | silver |
| C. | green |
| D. | black |
| Answer» B. silver | |
| 244. |
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 | |
| 245. |
The time constant of a series RL circuit is |
| A. | LR |
| B. | L/R |
| C. | R/L |
| D. | e^(-R/L) |
| Answer» D. e^(-R/L) | |
| 246. |
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 | |
| 247. |
A two branch parallel tuned circuit has a coil of resistance 100 Ω and inductance 0.005 H in one branch and 10 nF capacitor in the second branch. At resonance frequency is |
| A. | 100 rad/sec |
| B. | 10000 rad/sec |
| C. | 1000 rad/sec |
| D. | more than 10000 rad/sec |
| Answer» D. more than 10000 rad/sec | |
| 248. |
Which one of the following functions is RC driving point impedance? |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 249. |
Current in a 2H inductance in 10e¯ᵗ A. Admittance of the inductor is |
| A. | -0.5 mho |
| B. | 0.5 mho |
| C. | 5 mho |
| D. | 10 mho |
| Answer» B. 0.5 mho | |
| 250. |
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° | |