InterviewSolution
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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
Which of the statement is correct? |
| Answer» Transistor circuits are analysed using h parameters. | |
| 152. |
In the circuit of figure the current through 3 Ω resistance at = ∞ is |
| Answer» Since capacitor is open circuited at t = ∞, current 20/8 A. | |
| 153. |
In figure, (0) and (0) are zero. The switch is closed at = 0, (0) and (∞) are |
| Answer» At i = 0 applied voltage = 3V and current must be 3A. At i = ∞ source voltage is zero and current must be zero. | |
| 154. |
KVL equation for the circuit of figure is |
| Answer» The dots indicate that M term in KVL equation will be negative. | |
| 155. |
A loudspeaker transformer has a turns ratio of 20 : 1. The speaker impedance is 20Ω. Primary impedance of transformer is |
| Answer» . ZL 20 x 400 8000 8kΩ. | |
| 156. |
A series RLC circuit has a resonance frequency of 1 kHz and a quality factor Q = 100. If each of R, L and C is doubled from its original value, the new Q of the circuit is |
| Answer» , If R, C are doubled then . | |
| 157. |
A dc network has an open circuit voltage of 5 V. When its terminals are short circuited a current of 5 A flows through the short circuit. If the short circuit is removed and a resistance of 1.5 Ω is connected across its terminals, the current will be |
| Answer» | |
| 158. |
A coil of resistance R and inductance L has a capacitor C in parallel with it. The source frequency is adjusted to a value equal to resonant frequency. Another capacitor C is added in parallel with the above circuit, the source current will |
| Answer» The circuit will not in resonance. In parallel resonant circuit the current is minimum at resonance. Therefore, current will increase. | |
| 159. |
A series circuit has R = 5 Ω and C = 10 μF. At = 0 it is switched on to a 10 V dc battery. The maximum current in the circuit is |
| Answer» | |
| 160. |
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 |
| Answer» . | |
| 161. |
An AC circuit has two branches in parallel. The current in one branch is 5 A. Then the current source |
| Answer» 5 A current may be (say) 3 + j 4A. The current in the other branch is x ± jy. The total current is (3 + x) + (4 ± y). This may be 5A or more or less. | |
| 162. |
The electrolyte in a dry cell is completely dry. |
| Answer» The electrolyte is moist. | |
| 163. |
A series RLC circuit has a resonant frequency of 2000 Hz. The maximum voltage across C is likely to occur at a frequency of about |
| Answer» The maximum voltage across inductance occurs at a frequency slightly above the resonant frequency. | |
| 164. |
In the network shown in figure, the voltage drops across R and R are 10 V and 16 V with polarities as shown. The current in R |
| Answer» Current through R2 = 5 A towards 0. Current through R3 is 4 A away from node. Total incoming current = 13 A. Current going away from 0 and flowing through R1 = 9 A. | |
| 165. |
A coil has a resistance of 2 Ω and inductance of 0.1 mH. The applied voltages is suddenly increased from 10 V to 20 V. After steady state condition have reached, the current is |
| Answer» The final steady state current in RL circuit depends only on final voltage (i.e., 20 V) and resistance. | |
| 166. |
In the Bode plot, of , the phase at = 15 is |
| Answer» . | |
| 167. |
The inductance of an air cored coil is 2 H. The number of turns is made 3 times, all other quantities remaining the same. The new value of inductance will be 2 2 |
| Answer» Inductance a N2. | |
| 168. |
A non-linear element has zero resistance. |
| Answer» A non-linear element has a resistance which depends on the magnitude of current. | |
| 169. |
In a RL circuit, the angle, θ by which the current lags the voltage is |
| Answer» In RL circuit the current lags the voltage by an angle which is greater than 0° but less than 90°. | |
| 170. |
In an R-L circuit excited by a battery of voltage E, the current and voltage across resistor are 1- and 2(1 - ) respectively. If there were an initial current of 2 A in the inductance, the voltage across resistance would have been |
| Answer» From the given data R = 2Ω, L = 2H and E = 2V. Because of initial current of 2A, i(t) = 1 - e-t + 2e-t = 1 + e-t. Therefore, VR = 2(1 + e-t). | |
| 171. |
Stray capacitance is important at low frequencies. |
| Answer» At high frequencies the reactances of stray capacitance is small. Therefore stray capacitance assumes importance at high frequencies. | |
| 172. |
A choke coil has a resistance to reactance ratio of 0.2. The power factor of the choke coil is |
| Answer» Therefore, cos Ω = 0.196 lagging. | |
| 173. |
For the ladder network of figure, open circuit driving point impedance at port 1 = |
| Answer» s domain impedance of each inductance = 2s and that of each capacitor is . | |
| 174. |
- relation for a capacitor is |
| Answer» . | |
| 175. |
The time constant of the circuit in figure is |
| Answer» | |
| 176. |
The damping coefficient for the given circuit is __________ |
| Answer» Damping coefficient σ = u 1/2. | |
| 177. |
A 60 W, 23 V bulb is used for 45 minutes. The electrical energy consumed in commercial units is |
| Answer» | |
| 178. |
In an ideal current source, the source resistance is zero. |
| Answer» In ideal current source, the source resistance is infinite. | |
| 179. |
If V, V, V are sequence components of V and I, I, I are sequence components of I, then total 3 phase power P is given by |
| Answer» There are a total of 9 components (Three for each phase). Moreover, in general, P = VI*. | |
| 180. |
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 |
| Answer» Since capacitors are in series, charge will be same. | |
| 181. |
A series RLC circuit has Q = 5. A voltage of 10 V rms is applied to it. At resonance, the voltage across C is |
| Answer» VC = QV = 50 V rms. | |
| 182. |
In a practical current source, the load current |
| Answer» In a current source the source resistance is in parallel with the source. Some current flows through this source resistance. | |
| 183. |
The pole zero diagram of an impedance Z has a pole at = - 6 and zero at = - 4 as shown in figure the constant multiplier = 1. For a signal I = cos 6, the steady state voltage across Z is given in magnitude as under |
| Answer» . | |
| 184. |
A resistor R of 1 Ω and two inductor L and L of inductances 1 H and 2 H respectively, are connected in parallel. At some time, the current through L and L are 1 A and 2 A, respectively. The current through R at time = ∞ will be |
| Answer» Resistor will get short circuited. | |
| 185. |
In figure the open circuit emf is |
| Answer» Since emfs of two cells are not equal, a circulating current flows. . OC emf = 1.5 - (0.25)(0.1) = 1.475 V. | |
| 186. |
The pole of a reactive function |
| Answer» A reactance function means that the network is composed of only L and C. Since there is no resistance, poles lie on jω axis only. | |
| 187. |
In the circuit of figure the current through 3 Ω resistance at = 0 is |
| Answer» The 3Ω resistance is short-circuited by capacitor at t = 0. | |
| 188. |
Wave A starts its positive half cycle at ω = 30° and wave B starts its positive half cycle at ω = 75° then wave B is leading wave A by 45°. |
| Answer» B is lagging A by 45°. | |
| 189. |
In the circuit of figure the switch is open for a long time, At = 0 the switch is closed. At = 0 the current supplied by battery is |
| Answer» Inductance does not allow the current to change instantaneously. | |
| 190. |
A capacitor having capacitance C is raised to voltage V. The energy stored will be |
| Answer» Energy stored = 0.5 CV2 | |
| 191. |
The strength of controlled voltage source depends on |
| Answer» A controlled voltage source may be a voltage source or current source and its strength may depend on another voltage or current. | |
| 192. |
An RL series circuit is initially relaxed. A step voltage E is applied. If is time constant, voltage across R and L will be equal at = |
| Answer» vR = E(1 - e-t/t) and vL = E e-t/t or 1 - e-t/t = e-t/t. This happens at t = t in 2. | |
| 193. |
For the two port of figure, is |
| Answer» | |
| 194. |
A certain network has two ideal voltages sources and a large number of ideal resistances. The power consumed in one of the resistances is 4 W when either of two sources is active and the other source is active and the other source is short circuited. When both sources is short circuited.When both sources are active, the power consumed in the same resistor would be |
| Answer» If currents of both sources add, total current would be twice and power is four time, i.e., 16 W. If currents subtract, net current and power are zero. | |
| 195. |
A coil of resistance R and inductance L is connected in series with 5 μF capacitor. The source frequency is equal to resonance frequency and circuit current is 0.5 A. Another 5 F capacitor is connected in parallel with the above capacitor. The circuit current will be |
| Answer» Since C increases, the circuit will not be in resonance. Therefore, current decreases (In series resonant circuit current is maximum at resonance). | |
| 196. |
If the and T circuits in figure are equivalent, then R, R, R respectively are |
| Answer» Find R1, R2, R3 by delta star conversion. | |
| 197. |
In figure, the steady state current through 1H inductance is |
| Answer» In steady state inductance behaves as short-circuit. | |
| 198. |
Impedance Z as shown in the given figure is |
| Answer» Z = j5 + j2 + j2 + 20j - 20j = 9jΩ. | |
| 199. |
A resistance R, inductance L and capacitance C are in series. The source frequency is adjusted to be equal to resonant frequency. The lower half power frequency is ω. Another resistance R is added in series with the circuit. The new lower half power frequency will be |
| Answer» As R increases, Q decreases, bandwidth = . Therefore, bandwidth increases. Hence lower half power frequency will be less than ωr. | |
| 200. |
In an R-L circuit, the impedance is 30 Ω at a frequency of 100 Hz. At 200 Hz, the impedance should be |
| Answer» Z = (R2 + ω2L2)0.5. | |