577 + Interview Questions in Networks Analysis and Synthesis in Electronics and Communication Engineering Page 3 InterviewSolution

101.	If A = 3 + 1 and B = 4 + 3, A + B =
Answer» A + B = 7 + j4 = 8.062∠29.7°

Discussion

102.	When a constant voltage source and constant current source are in series, the current source is ineffective.
Answer» The voltage source is ineffective.

Discussion

103.	In an ac series RLC circuit the maximum phase difference between any two voltages can be
Answer» Voltage across inductance leads the current by 90° and voltage across capacitance lags the current by 90°.

Discussion

104.	In a series circuit with X constant and R variable the current locus lies in the third quadrant.
Answer» it lies in fourth quadrant.

Discussion

105.	One coulomb charge is equal to the charge on
Answer» As per definition 1C = 6.24 x 1018 electrons.

Discussion

106.	A wave trap is a
Answer» It has R and L in one branch and a variable capacitance in second branch.

Discussion

107.	An derived low pass filter has = 1000 Hz and = 0.6. This filter will have infinite attenuation at
Answer» For m derived low pass filter

Discussion

108.	In figure, () is a unit step current. The steady state value of () is
Answer» In steady state inductance is short-circuited and capacitance is open circuited. Current through 6&ohm; resistance = and

Discussion

109.	A current 10 sin (200) A flows through a 5 mH inductance. The expression for voltage is
Answer» Z = jXL = jωL = = 1∠90° and V = IXL

Discussion

110.	In figure, which value of Z will cause maximum power to be transferred to the load?
Answer» As seen from ZL, the circuit impedance =

Discussion

111.	Two capacitor of 1 F each are connected in parallel. Another 1 F capacitor is connected in series with the parallel combination. The total capacitance is
Answer»

Discussion

112.	The realization of the term Ks yields
Answer» Impedance of inductance K is sK.

Discussion

113.	The network has 10 nodes and 17 branches. The number of different node power voltages would be
Answer» Node pair voltage = number of node - 1.

Discussion

114.	For the time domain response shown in figure the pole
Answer» The response is unstable. Therefore pole is on positive real axis.

Discussion

115.	For the wave shown in figure, the average and rms values are
Answer» Area of triangle is half of rectangle. So average value = 0.5 x 100 = 50 A.

Discussion

116.	A 10 ohm resistance and a 10 ohm capacitor are connected in series across a 100 V ac supply. The rms voltage across resistance is
Answer»

Discussion

117.	The resonance frequency of the circuit is
Answer» Leq = 2 + 2 + 2 6 mH .

Discussion

118.	Twelve 1 &ohm; resistance are used as edges to form a cube. The resistance between two diagonally opposite corners of the cube is
Answer» .

Discussion

119.	A parallel RLC circuit has ω = 10 and Q = 30, Given C = 30 pF, the value of R is
Answer» .

Discussion

120.	The current wave shown in figure is applied at = 0 to a 0.1 F capacitor. At = 1 , the voltage across capacitor is
Answer» Q = 4 x 0.5 = 2C and

Discussion

121.	A capacitor can be represented by a capacitance C in parallel with a resistance R. For a good capacitor, the resistance R should be
Answer» Very high R will mean low dielectric loss.

Discussion

122.	If a sheet of a mica is inserted between the plates of an air capacitor, the capacitance
Answer» For mica ∈r is more than that of air.

Discussion

123.	The time constant of the circuit after the switch shown in the figure is opened is
Answer» .

Discussion

124.	A source of angular frequency 1 rad sec has a source impedance consisting of 1 &ohm; resistance in series with 1 H inductance. The load that will obtained the maximum power transfer is
Answer» According to question Z = R + jωL ω = 1, L = 1 Z = R + j max. power transfer will take place when Z = R - j C = 1.

Discussion

125.	Power is drawn from a source at power factor 0.7. P = 300 watt. The reactive power is
Answer» cos θ = 0.7 sin θ = 0.71 Pr = VI sin θ = x 300 x 0.7 107 VA.

Discussion

126.	The circuit in figure, is to be scaled to an impedance level of 5k&ohm; and resonant frequency of 5 x 10 rad/sec. The possible combination of R, L, C is
Answer» If L = 0.2 mH and C = 200 pF, ω0 = 5 x 106 rad/sec and if R is 5 k&ohm;, impedance level is 5 k&ohm;.

Discussion

127.	In figure, the total power consumed is
Answer» Use superposition theorem.

Discussion

128.	If operator '' = 1 ∠120° then (1 + ) =
Answer» Since 1 + a + a2 = 0, 1 + a = - a2.

Discussion

129.	A current wave is = 100 The initial and final values of current are
Answer» i(0) = 100 e-0 = 100, i(∞) = 100 e-∞ = 0.

Discussion

130.	KVL for second loop in figure is
Answer» emf induced in loop 2 due to i1 is

Discussion

131.	When two coupled coils of equal self inductance are cormected in series in one way the net inductance is 12 mH and when they are connected in the other way the net inductance is 4 mH. The maximum value of inductance when they are connected in parallel is
Answer» L1 = L2 = L = 4H. When in parallel effective inductance =

Discussion

132.	The number of electrons in motion at the instant of positive peak of a symmetrical ac wave is the same as that at the instant of negative peak.
Answer» Only directions are opposite.

Discussion

133.	In figure, the current through R, after the steady state condition is reached, is
Answer» At t = ∞ capacitor behaves as O.C.

Discussion

134.	A two branch parallel tuned circuit has 100 &ohm; resistance and 0.1 H inductance in one branch and 10 F capacitor in the other. At resonance frequency, the dynamic resistance is
Answer» Dynamic resistance =

Discussion

135.	A series R, L, C circuit has R = 2&ohm;, L = 1H, C = 1 μF. It is connected to an ac variable frequency source of peak voltage 10 V. At resonance the power supplied by the source will be
Answer»

Discussion

136.	In figure, the power associated with 3 A source is
Answer» Voltage across 4&ohm; resistance = source voltage = 8V. Power = 8 X 3 = 24 W.

Discussion

137.	In the circuit shown in figure the inductor current and capacitor voltage are given at a time . At this instant is __________ A and is __________ A/sec.
Answer» .

Discussion

138.	A material for permanent magnet should have
Answer» Only high retentivity will ensure permanent magnetism.

Discussion

139.	Two wires A and B have the same cross-section area and are made of the same material. R = 600 &ohm; and R = 100 &ohm;. The number of times A is longer than B is
Answer» RA = 600 &ohm;, RB = 100 &ohm;, .

Discussion

140.	A dc machine has 6 poles all connected in series. Each pole has 9 H inductance and field current is 2 A. Total inductance and total energy stored are
Answer» Total L = 6 x 9 = 54 H. Energy = x 54 x 22 = 108 J.

Discussion

141.	In a series RLC circuit the dB level of currents at half power frequencies as compared to current at resonance is
Answer» At half power frequencies, current is - 3 dB.

Discussion

142.	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 equal to
Answer» i = i0 (1 - e-R/Lt) and VR = VL at a given time t.

Discussion

143.	In figure, the transmission parameters are A = C = 1, B = 2 and D = 3. Then Z =
Answer»

Discussion

144.	A sinusoidal voltage is written as = I (R + X) sin 314 . Its peak value and frequency are
Answer» v2 = sin (ωt + 90°)

Discussion

145.	If A = 10 + then logA is
Answer» A = 14.14Ð45°, loge A = loge 14.14 x = 2.65 + j 0.785.

Discussion

146.	A system function is . The system is at rest for < 0, () = 2() where () is an unit step, V() for > 0 is given by
Answer» V(t) = 2e-6t.

Discussion

147.	In figure, the switch has been closed position for a long time. At = 0 the switch is opened. At = 0, the current is
Answer» Capacitor behaves as short-circuit at t = 0+.

Discussion

148.	For the port shown, the short circuit network function at port 2 is given by
Answer» If port 2 is short circuited then. .

Discussion

149.	In figure the rms value is
Answer» RMS value = 102 x 0.5 = 50.

Discussion

150.	The Laplace transforms of voltage function shown in figure is
Answer» The wave can be written as t u(t) - (t - a) u (t - a).

Discussion

Explore topic-wise InterviewSolutions in .

If A = 3 + 1 and B = 4 + 3, A + B =

When a constant voltage source and constant current source are in series, the current source is ineffective.

In an ac series RLC circuit the maximum phase difference between any two voltages can be

In a series circuit with X constant and R variable the current locus lies in the third quadrant.

One coulomb charge is equal to the charge on

A wave trap is a

An derived low pass filter has = 1000 Hz and = 0.6. This filter will have infinite attenuation at

In figure, () is a unit step current. The steady state value of () is

A current 10 sin (200) A flows through a 5 mH inductance. The expression for voltage is

In figure, which value of Z will cause maximum power to be transferred to the load?

Two capacitor of 1 F each are connected in parallel. Another 1 F capacitor is connected in series with the parallel combination. The total capacitance is

The realization of the term Ks yields

The network has 10 nodes and 17 branches. The number of different node power voltages would be

For the time domain response shown in figure the pole

For the wave shown in figure, the average and rms values are

A 10 ohm resistance and a 10 ohm capacitor are connected in series across a 100 V ac supply. The rms voltage across resistance is

The resonance frequency of the circuit is

Twelve 1 &ohm; resistance are used as edges to form a cube. The resistance between two diagonally opposite corners of the cube is

A parallel RLC circuit has ω = 10 and Q = 30, Given C = 30 pF, the value of R is

The current wave shown in figure is applied at = 0 to a 0.1 F capacitor. At = 1 , the voltage across capacitor is

A capacitor can be represented by a capacitance C in parallel with a resistance R. For a good capacitor, the resistance R should be

If a sheet of a mica is inserted between the plates of an air capacitor, the capacitance

The time constant of the circuit after the switch shown in the figure is opened is

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

Power is drawn from a source at power factor 0.7. P = 300 watt. The reactive power is

The circuit in figure, is to be scaled to an impedance level of 5k&ohm; and resonant frequency of 5 x 10 rad/sec. The possible combination of R, L, C is

In figure, the total power consumed is

If operator '' = 1 ∠120° then (1 + ) =

A current wave is = 100 The initial and final values of current are

KVL for second loop in figure is

When two coupled coils of equal self inductance are cormected in series in one way the net inductance is 12 mH and when they are connected in the other way the net inductance is 4 mH. The maximum value of inductance when they are connected in parallel is

The number of electrons in motion at the instant of positive peak of a symmetrical ac wave is the same as that at the instant of negative peak.

In figure, the current through R, after the steady state condition is reached, is

A two branch parallel tuned circuit has 100 &ohm; resistance and 0.1 H inductance in one branch and 10 F capacitor in the other. At resonance frequency, the dynamic resistance is

A series R, L, C circuit has R = 2&ohm;, L = 1H, C = 1 μF. It is connected to an ac variable frequency source of peak voltage 10 V. At resonance the power supplied by the source will be

In figure, the power associated with 3 A source is

In the circuit shown in figure the inductor current and capacitor voltage are given at a time . At this instant is __________ A and is __________ A/sec.

A material for permanent magnet should have

Two wires A and B have the same cross-section area and are made of the same material. R = 600 &ohm; and R = 100 &ohm;. The number of times A is longer than B is

A dc machine has 6 poles all connected in series. Each pole has 9 H inductance and field current is 2 A. Total inductance and total energy stored are

In a series RLC circuit the dB level of currents at half power frequencies as compared to current at resonance is

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 equal to

In figure, the transmission parameters are A = C = 1, B = 2 and D = 3. Then Z =

A sinusoidal voltage is written as = I (R + X) sin 314 . Its peak value and frequency are

If A = 10 + then logA is

A system function is . The system is at rest for < 0, () = 2() where () is an unit step, V() for > 0 is given by

In figure, the switch has been closed position for a long time. At = 0 the switch is opened. At = 0, the current is

For the port shown, the short circuit network function at port 2 is given by

In figure the rms value is

The Laplace transforms of voltage function shown in figure is

In the circuit shown in figure the inductor current and capacitor voltage are given at a time . At this instant is A and is A/sec.