577 + Interview Questions in Networks Analysis and Synthesis in Electronics and Communication Engineering Page 11 InterviewSolution

501.	If , the network has
Answer» which means 1 H inductance and 1 F capacitor in parallel.

Discussion

502.	The power dissipated in 4 &ohm; resistance in figure is
Answer» Current through 4&ohm; resistance = 2 A.

Discussion

503.	The total inductance of two coils is 60 mH in series aiding connection and 40 mH in series opposing connection. The mutual inductance between coils is
Answer»

Discussion

504.	The dual of network in figure is
Answer» L in series gives C in parallel of the same value and vice versa.

Discussion

505.	With I disconnected I = - 1, when I = b is connected, the value of I will become
Answer» I = -1 when Vs connected, when Is is open let find current in 2&ohm; resistor when V is shorted and I is connected. then I = -1 + 2 1 A.

Discussion

506.	In a resistor the current is and the voltage is . The rate of dissipation of heat at any time is
Answer» Rate of heat = rate of energy = power = vi.

Discussion

507.	When two port networks are connected in cascade, it is more convenient to use hybrid parameters.
Answer» It is more convenient to use transmission parameters.

Discussion

508.	The average value of periodic function () in figure is
Answer» .

Discussion

509.	A system function , the system is at rest for < 0. For ) = ), then ) is given by
Answer» .

Discussion

510.	Two voltages 50 V each have a phase difference of 45°. The rms value of resultant sum of the two voltages is
Answer» RMS value = (50 + 50 x 0.707)2 + (50 x .707)2.

Discussion

511.	In figure, power in 6 &ohm; resistor is zero then V =
Answer» Power in 6&ohm; resistor can be zero only if current in 6&ohm; resistor is zero. Therefore, voltages of nodes a and b are equal . Since equal resistances of 5&ohm; are on two sides of node b, .

Discussion

512.	The Thevenin's equivalent of network in figure(1) is a 10 V source in series with 2 &ohm; resistance. If a 3 &ohm; resistance is connected across AB as shown in figure(2) the Thevenin's equivalent is
Answer» .

Discussion

513.	If absolute potential of A is - 8 V and that of B is - 16 V, V is equal to
Answer» VAB = VA - VB or VAB = -8 - (-16) = 8 V.

Discussion

514.	An RLC series circuit is excited by 200 V, 100 Hz supply. The current is 20 A. If R = 10 &ohm;, X = 50 &ohm;, X is
Answer» = 10 &ohm; = 10 + y(50 - XC). Hence XC = 50 &ohm;

Discussion

515.	For a given voltage four heating coils will give maximum heat when connected
Answer» When in parallel each will get full voltage and hence maximum heat.

Discussion

516.	A system defined by is initially at rest, and = () sin 2 then the forced response is K sin (2 - θ). The value of θ given by
Answer» .

Discussion

517.	A two branch tuned circuit has a coil of resistance R and inductance L in one branch and capacitance C in the second branch. If R is increased, the dynamic resistance
Answer» Dynamic resistance = and increases as L is increased.

Discussion

518.	The driving point impedance of a network is The number of energy storing elements in the network is
Answer» Two energy storing elements give s2 terms.

Discussion

519.	Two currents have the same peak value. Wave 1 is sinusoidal and wave 2 is rectangular. The ratio of their heating effects are
Answer» If peak value is Im, heating effect of sine wave and heating effect of rectangular wave ∝ Im2.

Discussion

520.	If the transmission parameters of the given networks are A = C = 1, B = 2 and D = 3, then the value of Z is
Answer» .

Discussion

521.	In figure, the current through 10 V battery is
Answer» Since there is no return path, the current is zero.

Discussion

522.	When a lead acid cell is in fully charged condition the positive and negative plates are similar.
Answer» They are similar in discharged condition.

Discussion

523.	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
Answer» Q1 = 1 x 10-6 x 30 = 30 μC, Q2 = 2 x 10-6 x 30 = 60 μC.

Discussion

524.	In figure, the battery has remained switched on for a long time. At = 0 the switch is closed. The current () is likely to be
Answer»

Discussion

525.	A parallel RLC circuit with R = 20, is scaled giving R = 10, L = 10 and C, the value of C is
Answer» 0.02 x 10-8 0.2 nF.

Discussion

526.	A resistance coil has self inductance L, resistance R and capacitance C. The impedance across the coil is
Answer» The coil has R and L in series and C in parallel.

Discussion

527.	In figure, the current at = ∞ is
Answer» At t = ∞, inductance behaves as short-circuit.

Discussion

528.	Two similar coils have self inductance of 1 mH each. Coefficient of coupling is 0.5. The mutual inductance M is
Answer» M = kL1L2

Discussion

529.	A dielectric does not have leakage current.
Answer» All dielectrics have some leakage current.

Discussion

530.	A series RLC circuit has a resonant frequency of 1000 Hz. The maximum voltage across C is likely to occur at a frequency of about
Answer» Maximum voltage across capacitance occurs at a frequency slightly less than resonant frequency.

Discussion

531.	In figure, the value of R should be
Answer» The resistance of parallel combination =

Discussion

532.	In a parallel resonant circuit, the circuit current at resonance is maximum.
Answer» In parallel resonance current is minimum.

Discussion

533.	The rms value of wave in figure is
Answer»

Discussion

534.	An RLC series circuit is underdamped. To make it overdamped, the value of R
Answer» For overdamping R is more.

Discussion

535.	Henry is equivalent to
Answer» Inductance is flux per ampere.

Discussion

536.	In a minimum function
Answer» If degrees of numerator and denominator were unequal, a pole or zero can be removed. Such a function cannot be a minimum function. Therefore degrees of numerator and denominator must be equal.

Discussion

537.	When a current source I is suddenly connected across a two terminal relaxed RC circuit at time = 0, the voltage across the current source is shown in figure. The RC circuit is
Answer» Initially capacitor behaves as short-circuit and finally as open circuit.

Discussion

538.	The driving-point impedance Z() of a network has a pole-zero locations as shown in the figure. If Z(0) = 3, then Z () is
Answer» From figure, The impedance function and Z(0) = while in question Z(0) = 3 = 3 k = 2.

Discussion

539.	and () is a unit step, then V() in the steady state is given by
Answer» 0.444444444

Discussion

540.	For a transmission line open circuit and short circuit impedances are 20 &ohm; and 5 &ohm;. Then characteristic impedance is
Answer» Z0 = Zoc Zsc .

Discussion

541.	In an R-C series circuit excited by a voltage E, the charge across capacitor at = 0 is
Answer» Voltage across a capacitor cannot change instantaneously.

Discussion

542.	Two networks are cascaded through an ideal buffer. If and are delay times of network, the overall delay time is
Answer» In cascaded networks delay times are added.

Discussion

543.	The drift velocity of electrons is
Answer» Drift velocity of electrons is very small.

Discussion

544.	Wave A = 100 sin ω and wave B = 100 cos ω. Then
Answer» Since peak values are equal, their rms values are equal irrespective of phase difference.

Discussion

545.	A sinusoidal voltage has peak to peak value of 100 V. The rms value is
Answer» Peak value = 50 V, rms value = = 35.35 V.

Discussion

546.	A capacitor is needed for an ac circuit of 230 V, 50 Hz the peak voltage rating of the capacitor should be
Answer» Peak voltage rating = 2 (rms voltage rating).

Discussion

547.	The current wave shape shown in figure (1) is applied to a circuit element. The voltage across the element is shown in figure (2). The element is
Answer» When a current pulse is applied to a capacitor the voltage rises linearly and becomes constant at the end of pulse.

Discussion

548.	In figure, the current supplied by battery immediately after switching on the circuit is
Answer» At t = 0, inductance behaves as open circuit.

Discussion

549.	The terms RMS and average values apply only to sine waves.
Answer» These terms are applicable to all waveshapes.

Discussion

550.	A series RC circuit has R = 5 &ohm; and C = 10 μF. The current in the circuit is 5 sin 20000. The applied voltage is
Answer» Z = R2 + XC2 = 50 V = 550 sin(20000 t - 45°) V = 252 sin(20000 t - 45°)

Discussion

Explore topic-wise InterviewSolutions in .

If , the network has

The power dissipated in 4 &ohm; resistance in figure is

The total inductance of two coils is 60 mH in series aiding connection and 40 mH in series opposing connection. The mutual inductance between coils is

The dual of network in figure is

With I disconnected I = - 1, when I = b is connected, the value of I will become

In a resistor the current is and the voltage is . The rate of dissipation of heat at any time is

When two port networks are connected in cascade, it is more convenient to use hybrid parameters.

The average value of periodic function () in figure is

A system function , the system is at rest for < 0. For ) = ), then ) is given by

Two voltages 50 V each have a phase difference of 45°. The rms value of resultant sum of the two voltages is

In figure, power in 6 &ohm; resistor is zero then V =

The Thevenin's equivalent of network in figure(1) is a 10 V source in series with 2 &ohm; resistance. If a 3 &ohm; resistance is connected across AB as shown in figure(2) the Thevenin's equivalent is

If absolute potential of A is - 8 V and that of B is - 16 V, V is equal to

An RLC series circuit is excited by 200 V, 100 Hz supply. The current is 20 A. If R = 10 &ohm;, X = 50 &ohm;, X is

For a given voltage four heating coils will give maximum heat when connected

A system defined by is initially at rest, and = () sin 2 then the forced response is K sin (2 - θ). The value of θ given by

A two branch tuned circuit has a coil of resistance R and inductance L in one branch and capacitance C in the second branch. If R is increased, the dynamic resistance

The driving point impedance of a network is The number of energy storing elements in the network is

Two currents have the same peak value. Wave 1 is sinusoidal and wave 2 is rectangular. The ratio of their heating effects are

If the transmission parameters of the given networks are A = C = 1, B = 2 and D = 3, then the value of Z is

In figure, the current through 10 V battery is

When a lead acid cell is in fully charged condition the positive and negative plates are similar.

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

In figure, the battery has remained switched on for a long time. At = 0 the switch is closed. The current () is likely to be

A parallel RLC circuit with R = 20, is scaled giving R = 10, L = 10 and C, the value of C is

A resistance coil has self inductance L, resistance R and capacitance C. The impedance across the coil is

In figure, the current at = ∞ is

Two similar coils have self inductance of 1 mH each. Coefficient of coupling is 0.5. The mutual inductance M is

A dielectric does not have leakage current.

A series RLC circuit has a resonant frequency of 1000 Hz. The maximum voltage across C is likely to occur at a frequency of about

In figure, the value of R should be

In a parallel resonant circuit, the circuit current at resonance is maximum.

The rms value of wave in figure is

An RLC series circuit is underdamped. To make it overdamped, the value of R

Henry is equivalent to

In a minimum function

When a current source I is suddenly connected across a two terminal relaxed RC circuit at time = 0, the voltage across the current source is shown in figure. The RC circuit is

The driving-point impedance Z() of a network has a pole-zero locations as shown in the figure. If Z(0) = 3, then Z () is

and () is a unit step, then V() in the steady state is given by

For a transmission line open circuit and short circuit impedances are 20 &ohm; and 5 &ohm;. Then characteristic impedance is

In an R-C series circuit excited by a voltage E, the charge across capacitor at = 0 is

Two networks are cascaded through an ideal buffer. If and are delay times of network, the overall delay time is

The drift velocity of electrons is

Wave A = 100 sin ω and wave B = 100 cos ω. Then

A sinusoidal voltage has peak to peak value of 100 V. The rms value is

A capacitor is needed for an ac circuit of 230 V, 50 Hz the peak voltage rating of the capacitor should be

The current wave shape shown in figure (1) is applied to a circuit element. The voltage across the element is shown in figure (2). The element is

In figure, the current supplied by battery immediately after switching on the circuit is

The terms RMS and average values apply only to sine waves.

A series RC circuit has R = 5 &ohm; and C = 10 μF. The current in the circuit is 5 sin 20000. The applied voltage is